Puckett, Andrew W.; Rector, T. A., "A Killer Asteroids Research Project for Undergraduate Non-Majors," American Astronomical Society, AAS Meeting #213, #311.08, 01/2009.
Abstract:
We present a progress report on the development and testing of our Killer Asteroids Research Project, which enables the assessment of asteroid impact risk in the undergraduate classroom. This is part of an NSF CCLI grant to develop Research Based Science Education (RBSE) curricula for non-majors. Our curricula include six projects covering astrometric, photometric, and spectroscopic techniques, which are being tested at multiple schools of varying sizes around the country. We report on the second semester of testing this project with undergraduates at the University of Alaska Anchorage.
Students use our Polaris Plugin for ImageJ to perform both astrometry and aperture photometry on research-grade astronomical images. The output is fed into Find_Orb, which uses a Monte Carlo method to compute orbital elements for thousands of possible orbits. The resulting orbit database is then fed into a planetarium program, which allows students to visualize the uncertainty region and to observe how that region changes with time and/or additional data. For potentially hazardous asteroids, impact risk is assessed by counting the number of "clone” orbits that strike a planet's surface. Alternatively, the output from our plugin can be used directly to measure the lightcurves of minor planets, leading to an improved understanding of their shapes. This plugin is the first FITS reader to produce correct time-stamps for minor planet observations found in the SDSS, which observes in drift-scan mode.
Recent progress is promising. We are in dialogue with software engineers behind both Starry Night and Guide, helping to improve these planetarium programs as research tools. We are also constantly improving the Polaris Plugin, most recently to make it compatible with the astrometry format used by the websites NeoDys and AstDys.
Link: Abstract from the Smithsonian/NASA Astrophysics Data System
Link: Killer Asteroids Project Homepage
24 February 2009
1966 Paper on Manned Mission to Eros Using Apollo-Derived Hardware
Selections from the Blog entry on a March 1966 paper by Eugene Smith on a manned mission to Eros...
German astronomer Gustav Witt discovered the asteroid Eros on August 13, 1898. Eros was both the first asteroid found to orbit entirely outside of the Asteroid Belt and the first known planet-crosser; its path crosses that of Mars. In March 1966, Eugene Smith, an engineer at Northrop Space Laboratories in Hawthorne, California, presented a paper on a piloted Eros flyby mission at the Third Space Congress in Cocoa, Florida. In it, he wrote that Eros exploration might help scientists understand Main Belt asteroids and small planetary moons (for example, the martian satellites Deimos and Phobos). He noted that Eros would pass within 14 million miles of Earth in January 1975.
At the time Smith presented this paper, NASA and its contractors studied piloted free-return Mars and Venus flyby missions based on Apollo technology. The first of these was expected to leave Earth in 1975. Among other expected benefits, a Mars flyby would provide interplanetary flight experience ahead of 1980s piloted Mars landings. Smith noted, however, that a Mars flyby mission would likely be so heavy that placing all of its components and propellants into space would need either a Saturn V rocket with a nuclear upper stage or multiple all-chemical Saturn Vs followed by assembly in Earth orbit. He called instead for a 1975 piloted Eros flyby that would provide experience applicable to Mars landings, yet could depart Earth on a single uprated Saturn V rocket.
Smith argued that "the value of the Eros mission to subsequent manned planetary flights having a higher level of difficulty and complexity is of no small consequence." He added that "interplanetary experience comes only from interplanetary missions: less difficult flights, such as that to Eros, could significantly enhance experience acquired in Earth orbital and lunar activities, and could thereby increase the probability of success for the missions to follow."
Smith's 527-day Eros flyby mission would begin with launch and Earth departure on May 3, 1974, at the opening of a 30-day launch window. Upon arrival in 100-nautical-mile parking orbit, the Eros Flyby Spacecraft Vehicle (EFSV) would comprise a 33.6-ton Eros Command Module/Eros Service Module (ECM/ESM), a 33.2-ton Eros Mission Module (EMM), and a 98.6-ton Apollo Saturn V S-IVB stage, for a total mass of 165.4 tons. The ECM would be based on the conical Apollo Command Module design.
At the time Smith presented his paper, the Apollo Saturn V had yet to fly, but NASA expected that it would be able to launch about 130 tons into 100-nautical-mile parking orbit. Smith cited studies that proposed boosting Saturn V launch capacity to 165 tons by uprating the four J2 engines in its S-II second stage. Alternately, the rocket's S-IC first stage could be fitted with twin 260-inch-diameter solid-propellant strap-on boosters so that it could launch about 215 tons. This, Smith wrote, would provide ample margin for EFSV weight growth during development.
Link: Blog entry on 1966 Paper on Eros Manned Mission
German astronomer Gustav Witt discovered the asteroid Eros on August 13, 1898. Eros was both the first asteroid found to orbit entirely outside of the Asteroid Belt and the first known planet-crosser; its path crosses that of Mars. In March 1966, Eugene Smith, an engineer at Northrop Space Laboratories in Hawthorne, California, presented a paper on a piloted Eros flyby mission at the Third Space Congress in Cocoa, Florida. In it, he wrote that Eros exploration might help scientists understand Main Belt asteroids and small planetary moons (for example, the martian satellites Deimos and Phobos). He noted that Eros would pass within 14 million miles of Earth in January 1975.
At the time Smith presented this paper, NASA and its contractors studied piloted free-return Mars and Venus flyby missions based on Apollo technology. The first of these was expected to leave Earth in 1975. Among other expected benefits, a Mars flyby would provide interplanetary flight experience ahead of 1980s piloted Mars landings. Smith noted, however, that a Mars flyby mission would likely be so heavy that placing all of its components and propellants into space would need either a Saturn V rocket with a nuclear upper stage or multiple all-chemical Saturn Vs followed by assembly in Earth orbit. He called instead for a 1975 piloted Eros flyby that would provide experience applicable to Mars landings, yet could depart Earth on a single uprated Saturn V rocket.
Smith argued that "the value of the Eros mission to subsequent manned planetary flights having a higher level of difficulty and complexity is of no small consequence." He added that "interplanetary experience comes only from interplanetary missions: less difficult flights, such as that to Eros, could significantly enhance experience acquired in Earth orbital and lunar activities, and could thereby increase the probability of success for the missions to follow."
Smith's 527-day Eros flyby mission would begin with launch and Earth departure on May 3, 1974, at the opening of a 30-day launch window. Upon arrival in 100-nautical-mile parking orbit, the Eros Flyby Spacecraft Vehicle (EFSV) would comprise a 33.6-ton Eros Command Module/Eros Service Module (ECM/ESM), a 33.2-ton Eros Mission Module (EMM), and a 98.6-ton Apollo Saturn V S-IVB stage, for a total mass of 165.4 tons. The ECM would be based on the conical Apollo Command Module design.
At the time Smith presented his paper, the Apollo Saturn V had yet to fly, but NASA expected that it would be able to launch about 130 tons into 100-nautical-mile parking orbit. Smith cited studies that proposed boosting Saturn V launch capacity to 165 tons by uprating the four J2 engines in its S-II second stage. Alternately, the rocket's S-IC first stage could be fitted with twin 260-inch-diameter solid-propellant strap-on boosters so that it could launch about 215 tons. This, Smith wrote, would provide ample margin for EFSV weight growth during development.
Link: Blog entry on 1966 Paper on Eros Manned Mission
NEO News (02/24/09) Texas fireball & Nova show
NEO News (02/24/09): Texas fireball & Nova show [From Dave Morrison]:
TEXAS FIREBALL ON FEBRUARY 16
The recent daylight fireball in Texas received considerable press attention because it came shortly after the collision of US and Russian satellities. There was speculation that this might be a fragment from that collision rather than a natural meteor. That issue is apparently settled by the following message from Peter Brown of Western Ontario University in Canada. "I have been catching up with details of the Texas fireball -- it appears to be an L5 chondrite and seems to have produced numerous fragments on the ground. Clearly not related to the satellite collision of a few weeks back."
As background, there was no reason to assume that the fireball seen in Texas on February 16 was not a natural meteor. Objects this size collide with the Earth every few days. They vaporize or explode in the atmosphere, often (but not always) providing a few small solid fragments that fall to the ground as meteorites. Note that these meteorites fall at normal free-fall velocities (not cosmic speeds) and that they are usually cold by the time they reach the ground. Since the meteorites are cool when they reach the ground, we would not expect "scorched ground" or fires at the impact point.
=========================
NOVA PROGRAM ON EXTINCTION OF NORTH AMERICAN MEGAFAUNA
NEO News has reported previously on the hypothesis that a massive comet explosion (or cloud of thousands of comets) was responsible for the megafauna extinction in North America about 13,000 years ago. We have been skeptical because of the difficulty of imagining a massive impact that left no craters, spread its effects over thousands of kilometers, but was focused just on North America. A new paper on the discovery of nano-diamonds at several Clovis sites dating from this time is in press in Science. In addition, this hypothesis is the subject of a Nova documentary to be shown on PBS a month from now (described below). One of the unusual aspects is the close collaboration between the science team and the film-makers, with one of the Nova staff appearing as a co-author on the Science paper. Perhaps this is a direction science will move in the future, with coordinated journal publication and release of a TV documentary to reach a broader public audience.
NOVA: Last Extinction (Airs Tuesday, March 31)
What killed the mastodons? Thirteen thousand years ago, these tusked beasts disappeared from North America, along with some 35 genera of oversized mammals, including woolly mammoths, saber-tooth cats and even camels. For four decades, debate has raged over the cause of this extinction. In LAST EXTINCTION, NOVA presents an exclusive investigation of a startling and controversial new hypothesis which suggests that a cosmic collision could be the culprit. If a comet exploded in the upper atmosphere over the Great Lakes, the blast would have vaporized everything within a 100-mile radius. From coast to coast, wildfires would have raged and turned forests into cinder. Now, at more than two dozen sites across the continent, a multidisciplinary team finds evidence that just such a fire once ravaged North America. But other scholars argue that ancient hunters armed with a distinctive, lethal stone weapon -- the Clovis spear point -- drove the giant beasts into oblivion. Still others believe the unstable climate at the end of the Ice Age was responsible. Now the dramatic new evidence of a cosmic explosion suggests a third possibility -- that mammoths and mastodons already stressed out by human 'overkill' and climate change may have received a fiery coup-de-grace as devastation swept across the continent.
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
TEXAS FIREBALL ON FEBRUARY 16
The recent daylight fireball in Texas received considerable press attention because it came shortly after the collision of US and Russian satellities. There was speculation that this might be a fragment from that collision rather than a natural meteor. That issue is apparently settled by the following message from Peter Brown of Western Ontario University in Canada. "I have been catching up with details of the Texas fireball -- it appears to be an L5 chondrite and seems to have produced numerous fragments on the ground. Clearly not related to the satellite collision of a few weeks back."
As background, there was no reason to assume that the fireball seen in Texas on February 16 was not a natural meteor. Objects this size collide with the Earth every few days. They vaporize or explode in the atmosphere, often (but not always) providing a few small solid fragments that fall to the ground as meteorites. Note that these meteorites fall at normal free-fall velocities (not cosmic speeds) and that they are usually cold by the time they reach the ground. Since the meteorites are cool when they reach the ground, we would not expect "scorched ground" or fires at the impact point.
=========================
NOVA PROGRAM ON EXTINCTION OF NORTH AMERICAN MEGAFAUNA
NEO News has reported previously on the hypothesis that a massive comet explosion (or cloud of thousands of comets) was responsible for the megafauna extinction in North America about 13,000 years ago. We have been skeptical because of the difficulty of imagining a massive impact that left no craters, spread its effects over thousands of kilometers, but was focused just on North America. A new paper on the discovery of nano-diamonds at several Clovis sites dating from this time is in press in Science. In addition, this hypothesis is the subject of a Nova documentary to be shown on PBS a month from now (described below). One of the unusual aspects is the close collaboration between the science team and the film-makers, with one of the Nova staff appearing as a co-author on the Science paper. Perhaps this is a direction science will move in the future, with coordinated journal publication and release of a TV documentary to reach a broader public audience.
NOVA: Last Extinction (Airs Tuesday, March 31)
What killed the mastodons? Thirteen thousand years ago, these tusked beasts disappeared from North America, along with some 35 genera of oversized mammals, including woolly mammoths, saber-tooth cats and even camels. For four decades, debate has raged over the cause of this extinction. In LAST EXTINCTION, NOVA presents an exclusive investigation of a startling and controversial new hypothesis which suggests that a cosmic collision could be the culprit. If a comet exploded in the upper atmosphere over the Great Lakes, the blast would have vaporized everything within a 100-mile radius. From coast to coast, wildfires would have raged and turned forests into cinder. Now, at more than two dozen sites across the continent, a multidisciplinary team finds evidence that just such a fire once ravaged North America. But other scholars argue that ancient hunters armed with a distinctive, lethal stone weapon -- the Clovis spear point -- drove the giant beasts into oblivion. Still others believe the unstable climate at the end of the Ice Age was responsible. Now the dramatic new evidence of a cosmic explosion suggests a third possibility -- that mammoths and mastodons already stressed out by human 'overkill' and climate change may have received a fiery coup-de-grace as devastation swept across the continent.
--
+++++++++++++++++++++++++++++++++++++++++++
NEO News (now in its fourteenth year of distribution) is an informal compilation of news and opinion dealing with Near Earth Objects (NEOs) and their impacts. These opinions are the responsibility of the individual authors and do not represent the positions of NASA, Ames Research Center, the International Astronomical Union, or any other organization. To subscribe (or unsubscribe) contact dmorrison@arc.nasa.gov. For additional information, please see the website http://impact.arc.nasa.gov. If anyone wishes to copy or redistribute original material from these notes, fully or in part, please include this disclaimer.
Overview of ROSETTA Flyby of Asteroid 2867 Steins
Summary document of the ROSETTA mission's flyby of asteroid asteroid 2867 Steins. From the bulletin...
Because Rosetta crosses the main asteroid belt twice during its long cruise, the mission was also given secondary scientific objectives: the flybys of asteroids Steins and Lutetia (2010). The spacecraft is now on its fourth orbit around the Sun and crossed the asteroid belt for the first time in September 2008. On 5 September, Rosetta passed asteroid 2867 Steins at a distance of about 800 km and at relative velocity of 8.6 km/s.
Closest approach [to asteroid Steins] was 802.6 km, occurring only four seconds later than the time estimated for planning purposes.
Link: THE FIRST EUROPEAN ASTEROID ‘FLYBY’: Rosetta operations for the flyby of asteroid 2867 Steins, Sylvain Lodiot et al (PDF)
Link: ESA Bulletin
Because Rosetta crosses the main asteroid belt twice during its long cruise, the mission was also given secondary scientific objectives: the flybys of asteroids Steins and Lutetia (2010). The spacecraft is now on its fourth orbit around the Sun and crossed the asteroid belt for the first time in September 2008. On 5 September, Rosetta passed asteroid 2867 Steins at a distance of about 800 km and at relative velocity of 8.6 km/s.
Closest approach [to asteroid Steins] was 802.6 km, occurring only four seconds later than the time estimated for planning purposes.
Link: THE FIRST EUROPEAN ASTEROID ‘FLYBY’: Rosetta operations for the flyby of asteroid 2867 Steins, Sylvain Lodiot et al (PDF)
Link: ESA Bulletin
23 February 2009
Planetary Defense Presentations This Week at Space, Propulsion and Energy Sciences International Forum - SPESIF 2009
Planetary Defense Presentations this week at the Space, Propulsion and Energy Sciences International Forum- SPESIF 2009, Huntsville, AL, Von Braun Center, February 24 - 26, 2009.
The session on planetary defense will be held on Wednesday, February 25, 2009 - South Hall, Ballroom 4 in session [C05] Planetary Defense and Societal Protection from 3:45 – 5:45 pm (Central US Time).
Here is the schedule.
Chairs:
- Jim Pass, Astrosociology Research Institute, Huntington Beach, CA
- Albert A. Harrison, Department of Psychology, University of California, Davis, CA
3:45pm
"Planning for the Potential Failure of Planetary Defense: An Astrosociological Approach"
Albert A. Harrison, Department of Psychology, University of California, Davis, CA
4:15pm
"The NASA NEO Observation Program and the Impact Threat Uncertainty for Society"
Lindley N. Johnson, NASA Headquarters, Washington, DC
4:45pm
"Initial Assessment of Recent NEO Response Strategies for the United Nations"
A. C. Charania, SpaceWorks Engineering, Inc., Atlanta, Georgia
Link: SEPSIF Conference Website
The session on planetary defense will be held on Wednesday, February 25, 2009 - South Hall, Ballroom 4 in session [C05] Planetary Defense and Societal Protection from 3:45 – 5:45 pm (Central US Time).
Here is the schedule.
Chairs:
- Jim Pass, Astrosociology Research Institute, Huntington Beach, CA
- Albert A. Harrison, Department of Psychology, University of California, Davis, CA
3:45pm
"Planning for the Potential Failure of Planetary Defense: An Astrosociological Approach"
Albert A. Harrison, Department of Psychology, University of California, Davis, CA
4:15pm
"The NASA NEO Observation Program and the Impact Threat Uncertainty for Society"
Lindley N. Johnson, NASA Headquarters, Washington, DC
4:45pm
"Initial Assessment of Recent NEO Response Strategies for the United Nations"
A. C. Charania, SpaceWorks Engineering, Inc., Atlanta, Georgia
Link: SEPSIF Conference Website
Article: "Amateur astronomer finds meteorites near Waco"
From the article...
It's hard to forget the image of a fireball in the sky caught on tape in broad daylight during last Sunday's Austin Marathon. Speculation ended as to what the fireball really was when experts determined that it was a meteor.
Now there's actual physical proof that it was a meteor. Amateur astronomer Doug Dawn and his team say they were able to find meteorites. Dawn's team analyzed the video footage shot by News 8 photographer Eddie Garcia. Dawn said there was a lot of information available in the film and it helped with calculations of where the material was coming from.
Rob Matson is an expert in Los Angeles who helped narrow the likely location of the meteorite's landfall. Dawn and his team already had radar data and immediately made their way out to the countryside in the Waco area.
The main mass was not found. With the help of area residents who reported observing the fall, the team immediately recognized and collected multiple tiny blackened, fusion crusted meteorite fragments.
Link: Article
It's hard to forget the image of a fireball in the sky caught on tape in broad daylight during last Sunday's Austin Marathon. Speculation ended as to what the fireball really was when experts determined that it was a meteor.
Now there's actual physical proof that it was a meteor. Amateur astronomer Doug Dawn and his team say they were able to find meteorites. Dawn's team analyzed the video footage shot by News 8 photographer Eddie Garcia. Dawn said there was a lot of information available in the film and it helped with calculations of where the material was coming from.
Rob Matson is an expert in Los Angeles who helped narrow the likely location of the meteorite's landfall. Dawn and his team already had radar data and immediately made their way out to the countryside in the Waco area.
The main mass was not found. With the help of area residents who reported observing the fall, the team immediately recognized and collected multiple tiny blackened, fusion crusted meteorite fragments.
Link: Article
20 February 2009
Review of the Sundan meteorite impact story
From presentation by Lindley Johnson, NASA HQ NEO Office, to UN CONPUOS Science and Technical Subcommittee, 16 February 2009.
From the article...
The discovery of meteorites from an asteroid that exploded over Sudan in October completes an astronomical trifecta. For the first time, scientists have detected a space rock ahead of a collision with Earth, watched it streak through the atmosphere, and then recovered pieces of it. Analysis of the meteorites could shed light on conditions in the early solar system more than 4 billion years ago.
When the asteroid, called 2008 TC3, was discovered on 6 October last year, it was just 20 hours away from hitting Earth. Though the warning period was short, it was the first time a space rock had been found before it impacted the planet.
Orbital calculations predicted the object would plunge into the atmosphere above Sudan at 0246 GMT on 7 October, and it arrived right on time. Observations suggested it was no more than 5 metres across, too small to survive intact all the way to the ground and cause damage.
The brilliant fireball it made as it descended through the atmosphere was seen far in the distance by the crew of a KLM airliner, and was observed by various satellites, including a weather satellite called Meteosat-8.
Now, a team of meteorite hunters has found fragments of the object. The meteorites are a unique group in that they come from an object seen hurtling through space before its plunge into Earth's atmosphere.
Link: Article
19 February 2009
Eleanor "Glo" Helin Remembrance
ELEANOR "GLO" HELIN
Eleanor "Glo" Helin passed away in late January. She was one of the pioneers of the search for Near Earth objects (NEOs) and established and led the NEAT Project at JPL. The NEAT Program discovered hundreds of NEOs, many comets, and 64 Potentially Hazardous Asteroids (PHAs). Glo is survived by her son. If you would like to send him a note or card, his address is: Bruce Helin, 210 E. Elm St., Flagstaff, AZ 86001.
The entry on Wikipedia:
Eleanor Francis Helin is an American astronomer, who retired in 2002. She was principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASA's Jet Propulsion Laboratory. Some sources give her name as Eleanor Kay Helin.
Helin has discovered or co-discovered 872 asteroids, including the first two Aten asteroids: 2062 Aten and 2100 Ra-Shalom; the Apollo asteroids 4660 Nereus, 4769 Castalia and others; various Amor asteroids; three Trojan asteroids including 3240 Laocoon; and 9969 Braille.
She also discovered or co-discovered comets, including periodic comets 111P/Helin-Roman-Crockett, 117P/Helin-Roman-Alu and 132P/Helin-Roman-Alu.
Helin is credited as the discoverer of the object now known as both asteroid 4015 Wilson-Harrington and comet 107P/Wilson-Harrington. Although Wilson and Harrington preceded her by some decades, their observations did not establish an orbit for the object, while her rediscovery did.
Asteroid 3267 Glo is named for her ("Glo" is Helin's nickname).
Helin has been active in planetary science and astronomy at the California Institute of Technology and the Jet Propulsion Laboratory for over three decades. In the early 1970s, she initiated the Palomar Planet-Crossing Asteroid Survey (PCAS) from Palomar Observatory. This program is responsible for the discovery of thousands of asteroids of all types including more than 200 in high inclination orbits, other rare and unique orbital types of asteroids, 20 comets, and approximately 30 percent of the near-earth asteroids discovered worldwide.
Helin organized and coordinated the International Near-Earth Asteroid Survey (INAS) during the 1980s, encouraging and stimulating worldwide interest in asteroids. In recognition of her accomplishments, she has received NASA's Exceptional Service Medal. The 1997 JPL Award for Excellence was presented to Helin in recognition of her leadership of the Near-Earth Asteroid (NEAT) program. She has also received NASA's Group Achievement Award for the NEAT Team.
After conducting the PCAS photographic search program from Palomar for nearly 25 years, Helin concentrated on a new, upgraded search program using electronic sensors on a large aperture telescope: NEAT. She is the principal investigator for this program operating from JPL.
In operation since December 1995, NEAT is the first autonomous observing program; no JPL personnel are on-site, only the JPL Sunspark computer which runs the observing system through the night and transmits the data back to JPL each morning for team member review and confirmation. NEAT has detected over 26,000 objects, including 31 near-earth asteroids, two long period comets and the unique object, 1996 PW, the most eccentric asteroid known (e = 0.99012940), which moves in a long-period (4110.50 a), comet-like orbit (semi-major axis 256.601 AU).
Link: Wikipedia Entry
Eleanor "Glo" Helin passed away in late January. She was one of the pioneers of the search for Near Earth objects (NEOs) and established and led the NEAT Project at JPL. The NEAT Program discovered hundreds of NEOs, many comets, and 64 Potentially Hazardous Asteroids (PHAs). Glo is survived by her son. If you would like to send him a note or card, his address is: Bruce Helin, 210 E. Elm St., Flagstaff, AZ 86001.
The entry on Wikipedia:
Eleanor Francis Helin is an American astronomer, who retired in 2002. She was principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASA's Jet Propulsion Laboratory. Some sources give her name as Eleanor Kay Helin.
Helin has discovered or co-discovered 872 asteroids, including the first two Aten asteroids: 2062 Aten and 2100 Ra-Shalom; the Apollo asteroids 4660 Nereus, 4769 Castalia and others; various Amor asteroids; three Trojan asteroids including 3240 Laocoon; and 9969 Braille.
She also discovered or co-discovered comets, including periodic comets 111P/Helin-Roman-Crockett, 117P/Helin-Roman-Alu and 132P/Helin-Roman-Alu.
Helin is credited as the discoverer of the object now known as both asteroid 4015 Wilson-Harrington and comet 107P/Wilson-Harrington. Although Wilson and Harrington preceded her by some decades, their observations did not establish an orbit for the object, while her rediscovery did.
Asteroid 3267 Glo is named for her ("Glo" is Helin's nickname).
Helin has been active in planetary science and astronomy at the California Institute of Technology and the Jet Propulsion Laboratory for over three decades. In the early 1970s, she initiated the Palomar Planet-Crossing Asteroid Survey (PCAS) from Palomar Observatory. This program is responsible for the discovery of thousands of asteroids of all types including more than 200 in high inclination orbits, other rare and unique orbital types of asteroids, 20 comets, and approximately 30 percent of the near-earth asteroids discovered worldwide.
Helin organized and coordinated the International Near-Earth Asteroid Survey (INAS) during the 1980s, encouraging and stimulating worldwide interest in asteroids. In recognition of her accomplishments, she has received NASA's Exceptional Service Medal. The 1997 JPL Award for Excellence was presented to Helin in recognition of her leadership of the Near-Earth Asteroid (NEAT) program. She has also received NASA's Group Achievement Award for the NEAT Team.
After conducting the PCAS photographic search program from Palomar for nearly 25 years, Helin concentrated on a new, upgraded search program using electronic sensors on a large aperture telescope: NEAT. She is the principal investigator for this program operating from JPL.
In operation since December 1995, NEAT is the first autonomous observing program; no JPL personnel are on-site, only the JPL Sunspark computer which runs the observing system through the night and transmits the data back to JPL each morning for team member review and confirmation. NEAT has detected over 26,000 objects, including 31 near-earth asteroids, two long period comets and the unique object, 1996 PW, the most eccentric asteroid known (e = 0.99012940), which moves in a long-period (4110.50 a), comet-like orbit (semi-major axis 256.601 AU).
Link: Wikipedia Entry
17 February 2009
Organization Coordinating Work in Russia on NEOs
About a Russian approach to coordination of NEO research. The Russian Expert Working Group on The Comet and Asteroid Hazard Problem. Information from their website...
In Russia the research being bound up with different aspects of asteroid hazard is realized in many institutes and other organizations. At present, the coordinated approach to the asteroid hazard problem is required and it is appropriate to work in the context of the complex program where the Federal Space Agency (Roskosmos) could act as the State customer and coordinator and the Ministry of Industry and Energy of the Russian Federation, the Ministry of Defence of the Russian Federation, EMERCOM of Russia and the Russian Academy of Sciences - as customers.
With this purpose the Expert working group of the Space Council of the RAS on the problem of asteroid hazard on September, 15th, 2006 has been formed.
Link: EXPERT WORKING GROUP ON THE COMET AND ASTEROID HAZARD PROBLEM
In Russia the research being bound up with different aspects of asteroid hazard is realized in many institutes and other organizations. At present, the coordinated approach to the asteroid hazard problem is required and it is appropriate to work in the context of the complex program where the Federal Space Agency (Roskosmos) could act as the State customer and coordinator and the Ministry of Industry and Energy of the Russian Federation, the Ministry of Defence of the Russian Federation, EMERCOM of Russia and the Russian Academy of Sciences - as customers.
With this purpose the Expert working group of the Space Council of the RAS on the problem of asteroid hazard on September, 15th, 2006 has been formed.
Link: EXPERT WORKING GROUP ON THE COMET AND ASTEROID HAZARD PROBLEM
Presentations from UN COPUOS Now Online
There are several interesting presentations from the recent UN COPUOS meeting. They [some but not all presentations related to NEOS) are now available online and give good updates on search programs/statistics (from Lindley Johnson at NASA HQ), in-space observations missions (Canada), and other activities.
Link: Technical presentations made at the 46th session of Scientific and Technical Subcommittee
Link: Technical presentations made at the 46th session of Scientific and Technical Subcommittee
16 February 2009
Holocene Impact Working Group (HIWG)
From the website:
Ad hoc group called the Holocene Impact Working Group (HIWG) is a consortium of researchers and research groups from several countries that was created in early 2005 as follow-up the ICSU-sponsored Workshop on Comets/Asteroid Hazard held in the Canary Islands in December of 2004. The group includes the researchers and research teams from different field of geoscience who believe that Holocene impacts were more frequent in the recent past than the accepted view and that these impacts have played a significant role in past environmental change and biological and cultural/cognitive evolution. Evidence already collected by the group suggests that the large impacts on the Earth by comets and asteroids have taken place more recently and with greater frequency that presently argued by most NEO planetary scientists. The hypothesized oceanic/glacial impacts that are currently under study include the large comet impact over the Canadian ice shield some 13,000 years ago that triggered the beginning of the Younger Dryas climatic ordeal at 12,900 BP, the Burckle-Madagascar impact at round 4800-5000 BP, that may be associated with the Great (Noah's) Flood and the boundary change from middle to late Holocene around 4800 BP, the Gulf of Carpentaria impacts that are associated with "years without summers" climatic event 535-545 AD, and Mahuika crater just south of New Zealand that may be related to the beginning of the Little Ice Age at around 1450 AD. The focus of the current group activity is further search for physical, anthropological and archeological evidence in support of these and other impact events.
Link: Holocene Impact Working Group (HIWG) Website
Ad hoc group called the Holocene Impact Working Group (HIWG) is a consortium of researchers and research groups from several countries that was created in early 2005 as follow-up the ICSU-sponsored Workshop on Comets/Asteroid Hazard held in the Canary Islands in December of 2004. The group includes the researchers and research teams from different field of geoscience who believe that Holocene impacts were more frequent in the recent past than the accepted view and that these impacts have played a significant role in past environmental change and biological and cultural/cognitive evolution. Evidence already collected by the group suggests that the large impacts on the Earth by comets and asteroids have taken place more recently and with greater frequency that presently argued by most NEO planetary scientists. The hypothesized oceanic/glacial impacts that are currently under study include the large comet impact over the Canadian ice shield some 13,000 years ago that triggered the beginning of the Younger Dryas climatic ordeal at 12,900 BP, the Burckle-Madagascar impact at round 4800-5000 BP, that may be associated with the Great (Noah's) Flood and the boundary change from middle to late Holocene around 4800 BP, the Gulf of Carpentaria impacts that are associated with "years without summers" climatic event 535-545 AD, and Mahuika crater just south of New Zealand that may be related to the beginning of the Little Ice Age at around 1450 AD. The focus of the current group activity is further search for physical, anthropological and archeological evidence in support of these and other impact events.
Link: Holocene Impact Working Group (HIWG) Website
Napier and Asher Journal Article on NEOs Commenting on Threat from Comets
Napier and Asher talk about the threat from both asteroids and comets. Their preprint is available online.
"The Tunguska impact event and beyond"
Bill Napier and David Asher
Astronomy & Geophysics
Volume 50 Issue 1, Pages 1.18 - 1.26
Published Online: 16 Jan 2009
Abstract
Current strategies for dealing with the impact hazard are geared towards the detection and deflection of near-Earth asteroids, which typically have approach speeds ∼20 km s−1 and involve decades of warning. However, galactic signals in the age distribution of well-dated impact craters suggest that the globally destructive impactors (diameters between 1.5 and 2 km and upwards) ultimately derive from the Oort cloud. Warning times are then measured in months or days, and characteristic approach speeds are ∼55 km s−1. Concentrations of sub-kilometre debris in meteor streams may also be a significant regional hazard. Intersection with the debris of a large short-period comet may account for the widespread biological and cultural dislocation in North America around 12 900 BP.
Link: Preprint (PDF)
Link: Astronomy & Geophysics Citation
Link: COSMOS Magazine Article ("Earth under threat from dark comets," Monday, 16 February 2009, Heather Catchpole)
"The Tunguska impact event and beyond"
Bill Napier and David Asher
Astronomy & Geophysics
Volume 50 Issue 1, Pages 1.18 - 1.26
Published Online: 16 Jan 2009
Abstract
Current strategies for dealing with the impact hazard are geared towards the detection and deflection of near-Earth asteroids, which typically have approach speeds ∼20 km s−1 and involve decades of warning. However, galactic signals in the age distribution of well-dated impact craters suggest that the globally destructive impactors (diameters between 1.5 and 2 km and upwards) ultimately derive from the Oort cloud. Warning times are then measured in months or days, and characteristic approach speeds are ∼55 km s−1. Concentrations of sub-kilometre debris in meteor streams may also be a significant regional hazard. Intersection with the debris of a large short-period comet may account for the widespread biological and cultural dislocation in North America around 12 900 BP.
Link: Preprint (PDF)
Link: Astronomy & Geophysics Citation
Link: COSMOS Magazine Article ("Earth under threat from dark comets," Monday, 16 February 2009, Heather Catchpole)
NEO Activties at Recent UN COPUOS (February 2009)
During the most recent meeting of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) there were several presentations on NEO made on 16 February 2009. Here is a summary from notes of the meeting (Note, as of the evening of 16 February 2009 - US Eastern Time, the presentations for these NEO talks were not online, but they should be in the next few days).
COMMITTEE ON THE PEACEFUL USES OF OUTER SPACE
Scientific and Technical Subcommittee: 2009
Forty-sixth session
Vienna, Austria
9-20 February 2009
The Daily Journals for the Scientific and Technical Subcommittee
MONDAY, 16 FEBRUARY 2009
Special Presentations on Outer Space Activities
At the end of the morning session (708th) of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, today, 16 February 2009, there will be three special presentations on
- “Activities on the NEO problem in Russia” by Mr. Boris Shustov of the Russian Federation, on
- “NASA Near-Earth Object Observation Program” by Mr. Lindley Johnson of United States of America, on
- “The Canadian Near Earth Object Satellite Mission: NEOSSat” by Mr. David Kendall of Canada and on
- “Report on the French activities related to Apophis” by Mr. Jean-Yves Prado of France.
Special Presentations on Outer Space Activities
At the end of the afternoon session (709th) of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, today, 16 February 2009, there will be three special presentations on
- “Large Millimeter Telescope: Exploring the Origins of the Universe” by Mr. Alfonso Serrano of Mexico, on
- “An IAA study on dealing with the threat to Earth from Asteroids and Comets” by Mr. Ivan Bekey from International Academy of Astronautics (IAA), on
- “Asteroid Threats: A Call for Global Response” and on
- “Response of the IAF Technical Committee on Near-Earth Objects to the Association of Space Explorers proposal "Asteroid Threats: A Call for Global Response" by Mr. Alan Harris of Germany
Link: The Daily Journals for the Scientific and Technical Subcommittee of UN COPUOS for 16 February 2009 (in English)
Link: Technical presentations made at the 46th session of Scientific and Technical Subcommittee
Link: UN COPUOS
COMMITTEE ON THE PEACEFUL USES OF OUTER SPACE
Scientific and Technical Subcommittee: 2009
Forty-sixth session
Vienna, Austria
9-20 February 2009
The Daily Journals for the Scientific and Technical Subcommittee
MONDAY, 16 FEBRUARY 2009
Special Presentations on Outer Space Activities
At the end of the morning session (708th) of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, today, 16 February 2009, there will be three special presentations on
- “Activities on the NEO problem in Russia” by Mr. Boris Shustov of the Russian Federation, on
- “NASA Near-Earth Object Observation Program” by Mr. Lindley Johnson of United States of America, on
- “The Canadian Near Earth Object Satellite Mission: NEOSSat” by Mr. David Kendall of Canada and on
- “Report on the French activities related to Apophis” by Mr. Jean-Yves Prado of France.
Special Presentations on Outer Space Activities
At the end of the afternoon session (709th) of the Scientific and Technical Subcommittee of the Committee on the Peaceful Uses of Outer Space, today, 16 February 2009, there will be three special presentations on
- “Large Millimeter Telescope: Exploring the Origins of the Universe” by Mr. Alfonso Serrano of Mexico, on
- “An IAA study on dealing with the threat to Earth from Asteroids and Comets” by Mr. Ivan Bekey from International Academy of Astronautics (IAA), on
- “Asteroid Threats: A Call for Global Response” and on
- “Response of the IAF Technical Committee on Near-Earth Objects to the Association of Space Explorers proposal "Asteroid Threats: A Call for Global Response" by Mr. Alan Harris of Germany
Link: The Daily Journals for the Scientific and Technical Subcommittee of UN COPUOS for 16 February 2009 (in English)
Link: Technical presentations made at the 46th session of Scientific and Technical Subcommittee
Link: UN COPUOS
International Symposium Marco Polo and other Small Body Sample Return Missions
Information on the upomcing International Symposium Marco Polo and other Small Body Sample Return Missions (18-20 May 2009). The objectives of the workshop include (from the website):
The workshop objectives are to present the current status of the Marco Polo study activities within ESA and JAXA together with participations of international scientists, engineers and industries the international planning that are being put in place to make the mission happen. We also invite scientific presentations about the current state of asteroid research and sample analysis, in particular addressing the critical role played by NEO sample return missions, and presentations about possible payload elements, sampling requirements, mechanisms, and curation and analysis facilities.
This workshop will provide an opportunity for the wide planetary science community to interact with the Marco Polo Science Study Team, ESA and JAXA to further refine the mission's goals, its science drivers, and the required technology developments for the science payload.
Link: Workshop Site
The workshop objectives are to present the current status of the Marco Polo study activities within ESA and JAXA together with participations of international scientists, engineers and industries the international planning that are being put in place to make the mission happen. We also invite scientific presentations about the current state of asteroid research and sample analysis, in particular addressing the critical role played by NEO sample return missions, and presentations about possible payload elements, sampling requirements, mechanisms, and curation and analysis facilities.
This workshop will provide an opportunity for the wide planetary science community to interact with the Marco Polo Science Study Team, ESA and JAXA to further refine the mission's goals, its science drivers, and the required technology developments for the science payload.
Link: Workshop Site
Presentations from Recent ESA Workshop on GNC for Small Body Missions
Presentations from the recent (14-15 January 2009) ESA Workshop on GNC for Small Body Missions. Multiple presentations on proximity operations, update on Marco Polo, update on ASTEX Study, and other topics.
Link: ESA Conference Programme (with presentations)
Link: ESA Conference Programme (with presentations)
Poster Paper at Upcoming Lunar and Planetary Science Conference on Nuclear Deflection
There is a paper at the upcoming 40th Lunar and Planetary Science Conference (LPSC) on analysis of nuclear deflection options.
40th Lunar and Planetary Science Conference (2009)
Tuesday, March 24, 2009
POSTER SESSION I: ASTEROIDS AND COMETS
Title: "Modeling the Dynamic Response of an Asteroid or Comet to a Nuclear Deflection Burst"
Paper Number: [#2314]
Authors: Bradley P. A. Plesko C. S. Weaver R. P. Clement R. R. C. Guzik J. A. Pritchett-Sheats L. A. Huebner W. F.
Short abstract: The most technically feasible method of deflecting a Potentially Hazardous Object is a nuclear stand-off burst. We show results from our initial models that use bursts ranging from 1 to 1000 kt on 100 meter diameter targets of various compositions.
Portions of the long abstract:
There is much popular press about Potentially Hazardous Objects (PHOs) and how to mitigate their threat. The two mitigation options are destruction or deflection of the PHO. Presently, the most technically feasible method of deflection is a nuclear stand-off burst. However, many questions remain as to the response of an asteroid or comet to a nuclear burst. Recent increases in computing power and scientific understanding of the physical properties of asteroids and comets make it possible to numerically simulate the response of these porous and inhomogeneous bodies to strong shocks and radiation. Here we use the radiation-hydrocode RAGE to explore the coupling of the energy from a nuclear burst to a simplified PHO. We start with simple 1-D and 2-D models of material responses to variations in device yield, along the with composition and porosity of the PHO.
The NASA 2007 white paper “Near-Earth Object Survey and Deflection Analysis of Alternatives” [1] affirms deflection as the safest and most effective means of PHO impact prevention. It also calls for further studies of object deflection. In principle, deflection of a PHO may be accomplished using kinetic impactors, chemical explosives, gravity tractors, or nuclear munitions. Of these, nuclear munitions are by far the most efficient in terms of yield per unit mass launched and are technically mature. However, there are still significant questions about the response of a comet or asteroid to a nuclear burst. Previous calculations of deflection by nuclear munitions ([2], [3], [4], [5], and [6]) either do not assume a standoff burst and/or do not account for the substantial porosity or internal composition variations. These properties may substantially affect how a PHO responds to a standoff nuclear burst [7]. Several recent rendezvous and flyby missions to asteroids and comets showed their wide range of structure and composition, allowing us to model them better. In addition, we now have available computer codes that allow us to model the response of a simulated PHO to the energy from a nuclear burst.
Link: Abstract
Link: LPSC Poster Session List
40th Lunar and Planetary Science Conference (2009)
Tuesday, March 24, 2009
POSTER SESSION I: ASTEROIDS AND COMETS
Title: "Modeling the Dynamic Response of an Asteroid or Comet to a Nuclear Deflection Burst"
Paper Number: [#2314]
Authors: Bradley P. A. Plesko C. S. Weaver R. P. Clement R. R. C. Guzik J. A. Pritchett-Sheats L. A. Huebner W. F.
Short abstract: The most technically feasible method of deflecting a Potentially Hazardous Object is a nuclear stand-off burst. We show results from our initial models that use bursts ranging from 1 to 1000 kt on 100 meter diameter targets of various compositions.
Portions of the long abstract:
There is much popular press about Potentially Hazardous Objects (PHOs) and how to mitigate their threat. The two mitigation options are destruction or deflection of the PHO. Presently, the most technically feasible method of deflection is a nuclear stand-off burst. However, many questions remain as to the response of an asteroid or comet to a nuclear burst. Recent increases in computing power and scientific understanding of the physical properties of asteroids and comets make it possible to numerically simulate the response of these porous and inhomogeneous bodies to strong shocks and radiation. Here we use the radiation-hydrocode RAGE to explore the coupling of the energy from a nuclear burst to a simplified PHO. We start with simple 1-D and 2-D models of material responses to variations in device yield, along the with composition and porosity of the PHO.
The NASA 2007 white paper “Near-Earth Object Survey and Deflection Analysis of Alternatives” [1] affirms deflection as the safest and most effective means of PHO impact prevention. It also calls for further studies of object deflection. In principle, deflection of a PHO may be accomplished using kinetic impactors, chemical explosives, gravity tractors, or nuclear munitions. Of these, nuclear munitions are by far the most efficient in terms of yield per unit mass launched and are technically mature. However, there are still significant questions about the response of a comet or asteroid to a nuclear burst. Previous calculations of deflection by nuclear munitions ([2], [3], [4], [5], and [6]) either do not assume a standoff burst and/or do not account for the substantial porosity or internal composition variations. These properties may substantially affect how a PHO responds to a standoff nuclear burst [7]. Several recent rendezvous and flyby missions to asteroids and comets showed their wide range of structure and composition, allowing us to model them better. In addition, we now have available computer codes that allow us to model the response of a simulated PHO to the energy from a nuclear burst.
Link: Abstract
Link: LPSC Poster Session List
15 February 2009
Mexican Scientists Propose Converting 50 Meters Telescopr to Radar Observatory
Representatives from Mexico are having a press briefing during meetings of the United Nations Committee on the Peaceful Uses of Outer Space (UN COPUOS) to discuss transitioning Mexico's Large Millitmeter Telescipe (LMT) 50 meter dish into a radio telescope. Here are more details (if you are in Vienna):
Permanent Mission of Mexico to the United Nations
The Large Millimeter Telescope-Tracking and Characterizing Near Earth Objects
Tuesday, 17 February 2009, 10:00, Press Briefing Room, Vienna International Center, Room C03,
Presented by Dr. Alfsonso Serrano, Coordinator General, LMT Project
Link: Mexico LMT Site
Permanent Mission of Mexico to the United Nations
The Large Millimeter Telescope-Tracking and Characterizing Near Earth Objects
Tuesday, 17 February 2009, 10:00, Press Briefing Room, Vienna International Center, Room C03,
Presented by Dr. Alfsonso Serrano, Coordinator General, LMT Project
Link: Mexico LMT Site
14 February 2009
Fireball in 2008 linked to the breakup of a comet in 1920
Image: J. Madiedo, University of Huelva-CIECEM, Spain
From the article...
In a forthcoming paper in Monthly Notices of the Royal Astronomical Society, an international team of astronomers link a brilliant fireball seen in 2008 to the breakup of a comet in 1920.
Last July, people in Spain, Portugal and France watched the brilliant fireball produced by a boulder crashing down through the Earth’s atmosphere. In a paper to be published in the journal Monthly Notices of the Royal Astronomical Society, astronomers Josep M. Trigo-RodrÃguez (Institute of Space Sciences, CSIC-IEEC, Spain), José M. Madiedo (University of Huelva-CIECEM, Spain) and Iwan P. Williams (Queen Mary, University of London) present dramatic images of this event. The scientists go on to explain how the boulder may originate from a comet which broke up nearly 90 years ago and suggest the tantalising possibility that chunks of the boulder (and hence pieces of the comet) are waiting to be found on the ground.
Link: Article
12 February 2009
New Technique to Measure Asteroids' Sizes and Shapes
Artist’s impression of the asteroid (234) Barbara. Thanks to a unique method that uses ESO’s Very Large Telescope Interferometer, astronomers have been able to measure sizes of small asteroids in the main belt for the first time. Their observations also suggest that Barbara has a complex concave shape, best modelled as two bodies that may possibly be in contact.
Credit: ESO/L. Calçada
From the article...
A team of French and Italian astronomers have devised a new method for measuring the size and shape of asteroids that are too small or too far away for traditional techniques, increasing the number of asteroids that can be measured by a factor of several hundred. This method takes advantage of the unique capabilities of ESO's Very Large Telescope Interferometer (VLTI).
Direct imaging with adaptive optics on the largest ground-based telescopes such as the Very Large Telescope (VLT) in Chile (see ESO 21/05 and 18/07), and space telescopes, or radar measurements (ESO 11/07) are the currently favoured methods of asteroid measurement. However, direct imaging, even with adaptive optics, is generally limited to the one hundred largest asteroids of the main belt, while radar measurements are mostly constrained to observations of near-Earth asteroids that experience close encounters with our planet.
Delbo and his colleagues have devised a new method that uses interferometry to resolve asteroids as small as about 15 km in diameter located in the main asteroid belt, 200 million kilometres away. This is equivalent to being able to measure the size of a tennis ball a distance of a thousand kilometres. This technique will not only increase the number of objects that can be measured dramatically, but, more importantly, bring small asteroids that are physically very different from the well studied larger ones into reach.
The interferometric technique combines the light from two or more telescopes. Astronomers proved their method using ESO's VLTI, combining the light of two of the VLT's 8.2-metre Unit Telescopes. "This is equivalent to having vision as sharp as that of a telescope with a diameter equal to the separation between the two VLT Unit Telescopes used, in this case, 47 metres," says co-author Sebastiano Ligori, from INAF-Torino, Italy. The researchers applied their technique to the main belt asteroid (234) Barbara, which was earlier found, by co-author Alberto Cellino, to have rather unusual properties. Although it is so far away, the VLTI observations also revealed that this object has a peculiar shape. The best fit model is composed of two bodies each the size of a major city – with diameters of 37 and 21 km – separated by at least 24 km. "The two parts appear to overlap," says Delbo, "so the object could be shaped like a gigantic peanut or, it could be two separate bodies orbiting each other."
Link: Press Release
Link: Paper by paper by Delbo M. et al., "First VLTI-MIDI direct determinations of asteroid sizes," in press in the Astrophysical Journal.
International Meteor Conference: 24-27 September 2009, Porec, Croatia
International Meteor Conference 2009
September 24-27, 2009
Porec, Croatia
The International Meteor Organization (IMO) will hold its next annual International Meteor Conference (IMC) in Porec from September 24 till 27, 2009. Both amateur and professional astronomers are invited to this four-day event. The location of the conference is in the town Porec, located on the western coast of the Istria peninsula in northern Croatia.
Link: Conference Website
September 24-27, 2009
Porec, Croatia
The International Meteor Organization (IMO) will hold its next annual International Meteor Conference (IMC) in Porec from September 24 till 27, 2009. Both amateur and professional astronomers are invited to this four-day event. The location of the conference is in the town Porec, located on the western coast of the Istria peninsula in northern Croatia.
Link: Conference Website
Preliminary Agenda for the 2009 Planetary Defense Conference is Up
The preliminary agenda (speakers) for the 2009 Planetary Defense conference is up. This will be the premier international forum on the topic of asteroid detection, characterization, and mitigation. Thanks for Bill Ailor from the Aerospace Corporation, the European Space Agency (ESA), and International Academy of Astronautics (IAA).
Link: Conference Agenda
Link: Conference Website
Link: Conference Agenda
Link: Conference Website
2009 BD81: A new potentially hazardous asteroid
From the article...
While observing a known asteroid on January 31, 2009, astronomer Robert Holmes from the Astronomical Research Institute near Charleston, Illinois found another high speed object moving nearby through the same field of view. The object has now been confirmed to be a previously undiscovered Potentially Hazardous Asteroid (PHA), with several possible Earth impact risks after 2042. This relatively small near-Earth asteroid, named 2009 BD81, will make its closest approach to Earth in 2009 on February 27, passing a comfortable 7 million kilometers away. In 2042, current projections have it passing within 5.5 Earth radii, (approximately 31,800 km or 19,800 miles) with an even closer approach in 2046. Data from the NASA/JPL Risk web page show 2009 BD81 to be fairly small, with a diameter of 0.314 km (about 1000 ft.) Holmes, one of the world's most prolific near Earth object (NEO) observers, said currently, the chance of this asteroid hitting Earth in 33 years or so is quite small; the odds are about 1 in 2 million, but follow-up observations are needed to provide precise calculations of the asteroid's potential future orbital path.
Link: Article (Universe Today)
11 February 2009
Article on "Dark" Comets
From the article...
Hazardous comets and asteroids are monitored by various space agencies under an umbrella effort known as Spaceguard. The vast majority of objects found so far are rocky asteroids. Yet UK-based astronomers Bill Napier at Cardiff University and David Asher at Armagh Observatory in Northern Ireland claim that many comets could be going undetected. "There is a case to be made that dark, dormant comets are a significant but largely unseen hazard," says Napier.
In previous work, Napier and Janaki Wickramasinghe, also at Cardiff, have suggested that when the solar system periodically passes through the galactic plane, it nudges comets in our direction (New Scientist, 19 April 2008, p 10).
These periodic comet showers appear to correlate with the dates of ancient impact craters found on Earth, which would suggest that most impactors in the past were comets, not asteroids.
Now Napier and Asher warn that some of these comets may still be zipping around the solar system. Other observations support their case. The rate that bright comets enter the solar system implies there should be around 3000 of them buzzing around, and yet only 25 are known.
"There may be merit to this idea," says Steve Larson of the University of Arizona's Catalina Sky Survey in Tucson, one of the main contributors to Spaceguard.
Clark Chapman at the Southwest Research Institute in Boulder, Colorado, is sceptical, but points out that such dark comets "would absorb sunlight very well" and so could be detected by the heat they would emit.
Link: Article
Hazardous comets and asteroids are monitored by various space agencies under an umbrella effort known as Spaceguard. The vast majority of objects found so far are rocky asteroids. Yet UK-based astronomers Bill Napier at Cardiff University and David Asher at Armagh Observatory in Northern Ireland claim that many comets could be going undetected. "There is a case to be made that dark, dormant comets are a significant but largely unseen hazard," says Napier.
In previous work, Napier and Janaki Wickramasinghe, also at Cardiff, have suggested that when the solar system periodically passes through the galactic plane, it nudges comets in our direction (New Scientist, 19 April 2008, p 10).
These periodic comet showers appear to correlate with the dates of ancient impact craters found on Earth, which would suggest that most impactors in the past were comets, not asteroids.
Now Napier and Asher warn that some of these comets may still be zipping around the solar system. Other observations support their case. The rate that bright comets enter the solar system implies there should be around 3000 of them buzzing around, and yet only 25 are known.
"There may be merit to this idea," says Steve Larson of the University of Arizona's Catalina Sky Survey in Tucson, one of the main contributors to Spaceguard.
Clark Chapman at the Southwest Research Institute in Boulder, Colorado, is sceptical, but points out that such dark comets "would absorb sunlight very well" and so could be detected by the heat they would emit.
Link: Article
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