2007 WD5

Apollo and Mars-crosser asteroid January 2020 yes 2007 WD 5 #FA8072 2007wd5.jpg Simulated image of 2007 WD 5's approach of Mars, generated in Celestia. Image of an elliptical asteroid, labelled as 2007 WD5, passing by Mars. Phobos, another moon of Mars, can be seen in the distance. 20 November 2007 Mount Lemmon SurveyAndrea Boattini(unofficial credits) NEOApolloMars-crosser 21 November 2025 (JD 2461000.5) 2.4613 AU Gm on 0.99698 AU Gm on 3.9256 AU Gm on on 0.59494 3.86 yr (1410.4 d) 2.4358° 68.164° 310.468° 246.916° 27900 mi/h km/s on flip 50 m ft -1 on 24.3 0.25524 ms /day 60 0.0278204 AU Gm on 2007 WD 5 is an Apollo asteroid some 50 m ft -1 on in diameter and a Mars-crosser asteroid first observed on 20 November 2007, by Andrea Boattini of the Catalina Sky Survey. Early observations of 2007 WD 5 caused excitement amongst the scientific community when it was estimated as having as high as a 1 in 25 chance of colliding with Mars on 30 January 2008. However, by 9 January 2008, additional observations allowed NASA's Near Earth Object Program (NEOP) to reduce the uncertainty region resulting in only a 1-in-10,000 chance of impact. 2007 WD 5 most likely passed Mars at a distance of 6.5 Mars radii. Due to this relatively small distance and the uncertainty level of the prior observations, the gravitational effects of Mars on its trajectory are unknown and, according to Steven Chesley of NASA's Jet Propulsion Laboratory Near-Earth Object program, 2007 WD 5 is currently considered 'lost' (see lost asteroids).Lakdawalla Emily WD5 most likely missed Mars, but we may never know 4 February 2008 https://www.planetary.org/articles/1316 24 February 2008 https://web.archive.org/web/20080208111123/http://www.planetary.org/blog/article/00001316/ 8 February 2008 live Discovery The asteroid was discovered on 20 November 2007 by Andrea Boattini21 December 2007 Catalina Sky Survey Discovers Space Rock That Could Hit Mars The University of Arizona Lori Stiles, University Communications http://uanews.org/node/17415 https://web.archive.org/web/20080510115105/http://uanews.org/node/17415 usurped 10 May 2008 23 December 2007 of the NASA-funded Catalina Sky Survey on Mount Lemmon, near Tucson, Arizona, United States, using a 1.5-meter telescope.21 December 2007 Recently Discovered Asteroid Could Hit Mars in January NASA/JPL Near-Earth Object Program Office Steve Chesley Paul Chodas amp https://cneos.jpl.nasa.gov/news/news151.html 21 December 2007 https://web.archive.org/web/20071224120701/http://neo.jpl.nasa.gov/news/news151.html 24 December 2007 live It was discovered in the constellation Taurus at an apparent magnitude of +20. This is about 400,000 times fainter than most people can see with the naked eye on a dark night far from city lights. It was discovered nineteen days after passing near Earth. By the time it arrived at Mars it had an apparent magnitude of roughly +26 and therefore appeared over 100 times fainter than at the time of discovery.Horizons Brightness Difference between 11-20-07 and 01-30-08: (5th root of 100) ^ (@marsJan30th APmag 25.9 - DiscoveryNov20th APmag 20.2) = 190x Orbit thumb|Orbit of 2007 WD 5 2007 WD 5 orbits the Sun at a distance of 2.46 astronomical units. The orbit's eccentricity is 0.59 and its inclination is 2.4°. Mars encounter: chance of impact Timeline of observations and events 1 November 2007: Nineteen days before its discovery, this small asteroid passed within 7.5 million km (5 million miles or 0.0476 AU) of the Earth. 20 November 2007: The asteroid was first discovered by Andrea Boattini of the Catalina Sky Survey. 21 December 2007: 2007 WD 5 was approximately halfway between Earth and Mars traveling at 27900 mph on. It was estimated by NASA's Near Earth Object Program (NEOP) to have a 1-in-75 chance of colliding with Mars on 30 January 2008 at approximately 10:55 UT. It was thought it would pass about 50,000 km (0.00034AU) from Mars. 28 December 2007: NASA scientists at the Near-Earth Object program office at JPL announced they had found 2007 WD 5 in 3 precovery images from 8 November 2007. The refined orbit placed the odds of a Mars impact at 1-in-25. The uncertainty region was reduced from 1 million km to roughly 400,000 km.28 December 2007 Mars Impact Probability Increases to 4 Percent NASA/JPL Near-Earth Object Program Office Don Yeomans Paul Chodas Steve Chesley amp http://cneos.jpl.nasa.gov/news/news153.html 28 December 2007 https://web.archive.org/web/20071229233152/http://neo.jpl.nasa.gov/news/news153.html 29 December 2007 live The best fit trajectory had the asteroid passing within 21,000 km of Mars and only 16,000 km from the moon Deimos.http://home.surewest.net/kheider/astro/2007WD5.txt Horizons Archive Mars/Earth 2003/2008 23 December 2007 dead https://web.archive.org/web/20120309120516/http://home.surewest.net/kheider/astro/2007WD5.txt 9 March 2012 (Soln.date: 2007-Dec-23) The pre-discovery observations were located by Andy Puckett in the archive of the Sloan Digital Sky Survey II at the Apache Point Observatory. 2 January 2008: NASA scientists revised the probability of an impact with Mars to 1-in-28 after more observations were reported by Bill Ryan with the 2.4-meter telescope at New Mexico Tech's Magdalena Ridge Observatory. The uncertainty region was reduced to roughly 200,000 km and still intersected Mars, but the most likely path moved a little farther away from the planet.2 January 2008 New Observations Slightly Decrease Mars Impact Probability NASA/JPL Near-Earth Object Program Office Don Yeomans Paul Chodas Steve Chesley amp http://cneos.jpl.nasa.gov/news/news154.html 2 January 2008 https://web.archive.org/web/20080105134058/http://neo.jpl.nasa.gov/news/news154.html 5 January 2008 live 8 January 2008: NASA scientists revised the probability of an impact with Mars to 1-in-40 after refinements to the analysis of the Sloan precovery observations and observations with the 3.5 meter telescope at the Calar Alto Observatory in Spain. The uncertainty region was reduced by a factor of 3.8 January 2008 Mars Impact Seems Less Likely NASA/JPL Near-Earth Object Program Office Steve Chesley Paul Chodas Don Yeomans amp http://cneos.jpl.nasa.gov/news/news155.html 8 January 2008 https://web.archive.org/web/20080112075051/http://neo.jpl.nasa.gov/news/news155.html 12 January 2008 live 9 January 2008: Following several new observations, NASA reduced the uncertainty region and effectively ruled out a Mars collision. The chance of collision became only 1-in-10,000 (0.01%).9 January 2008 2007 WD5 Mars Collision Effectively Ruled Out - Impact Odds now 1 in 10,000 NASA/JPL Near-Earth Object Program Office Steve Chesley Paul Chodas Don Yeomans amp http://cneos.jpl.nasa.gov/news/news156.html 9 January 2008 https://web.archive.org/web/20080111142119/http://neo.jpl.nasa.gov/news/news156.html 11 January 2008 live The best estimate was that around 12:00 UTC the asteroid passed about 26,000 km (0.00017AU) from the planet's center (about 7 Mars radii from the surface). Analyses show there is no possibility of an impact with either Mars or Earth in the next century. This trend of increasing probability of impact followed by a dramatic decrease is typical as uncertainties are gradually reduced. In December 2004, a similar trend was observed with 99942 Apophis where the predicted probability of impact with Earth in 2029 at one point reached as high as 2.7%. thumb|NASA Animation showing the motion of the uncertainty region of 2007 WD 5 as it approaches Mars. The thin white line is the orbit of Mars. The blue line traces the motion of the center of the uncertainty region, which is the most likely position of the asteroid. Orbital data as known on 21 December 2007 Estimates of resulting impact right|thumb|Track of asteroid 2007 WD 5 over Mars (NASA/JPL) If the asteroid had collided with Mars, it would have hit with a velocity of about 13.5 km/s (8.4 miles per second), and would have produced an explosion equivalent to about 3 megatons of TNT. Due to the thin atmosphere of Mars, it was predicted that the asteroid would have reached the surface intact and blasted out a crater approximately 0.8 km mi 1 on in diameter.Johnson Jr. John Asteroid on track for possible Mars hit Los Angeles Times 21 December 2007 http://www.latimes.com/news/science/la-sci-mars21dec21,0,6729483.story?coll=la-home-center 21 December 2007 https://web.archive.org/web/20071222035734/http://www.latimes.com/news/science/la-sci-mars21dec21%2C0%2C6729483.story?coll=la-home-center 22 December 2007 live A crater this size would be equal to the size of the Meteor Crater in Arizona, United States. NASA officials say if it had hit Mars, it would have done so north of the location of the Opportunity rover. 2007 WD 5 is roughly the size of the cometary object that caused the Tunguska event in 1908, in remote central Siberia, Russia. Due to the Earth's greater gravity, an impact with the power of Tunguska is expected to occur once every few hundred years. Tunguska Revision, and a Possible NEA Impact on Mars Asteroid and Comet Impact Hazards (NASA) 21 December 2007 David Morrison http://impact.arc.nasa.gov/news_detail.cfm?ID=179 3 January 2008 https://web.archive.org/web/20080102075735/http://impact.arc.nasa.gov/news_detail.cfm?ID=179 2 January 2008 dead Since Mars has only 1/10 the mass to attract objects, these types of impacts occur roughly every one thousand years on Mars.Astronomers Monitor Asteroid to Pass Near Mars NASA/JPL 21 December 2007 http://www.jpl.nasa.gov/news/news.cfm?release=2007-152 22 December 2007 https://web.archive.org/web/20071224005122/http://www.jpl.nasa.gov/news/news.cfm?release=2007-152 24 December 2007 live Future encounters In July 2003, the asteroid passed within 0.012 AU of Mars.http://home.surewest.net/kheider/astro/2007WD5-0109.txt Horizons Output Mars/Earth 2003/2008 9 January 2008 dead https://web.archive.org/web/20150403220304/http://home.surewest.net/kheider/astro/2007WD5-0109.txt 3 April 2015 (Soln.date: 2008-Jan-09) The exact fate of 2007 WD 5 following the January 2008 Mars encounter is unknown although it likely passed Mars at a distance of 6.5 Mars radii. Mars, unlike Jupiter, is not big enough to eject the asteroid from the Solar System; however, the gravitation effect from the encounter on the asteroid's trajectory is uncertain and the asteroid is currently considered 'lost'. Assuming 2007 WD 5 passed Mars safely, its low inclination to the ecliptic of only 2.3 degrees and high eccentricity of 0.6 could cause it to swing close to Mars or Earth for years or decades into the future.October 2019 See also C/2013 A1 - Comet that passed extremely close to Mars on 19 October 2014 Comet Shoemaker–Levy 9 - Jupiter impact 1994 Impact events on Mars References 2008-01-09 last obs. JPL Small-Body Database Browser: 2007 WD5 http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2007wd5 Jet Propulsion Laboratory 2 February 2017 2007 WD5 Minor Planet Center http://www.minorplanetcenter.net/db_search/show_object?object_id=2007+WD5 2 February 2017 Absolute Magnitude (H) NASA/JPL http://cneos.jpl.nasa.gov/glossary/h.html https://web.archive.org/web/20010302182040/http://neo.jpl.nasa.gov/glossary/h.html live 2 March 2001 2 February 2017 External links CNEOS – Center for Near Earth Object Studies, JPL–NASA A Meteoroid Hits the Moon (25 cm wide) on 2 May 2006 Gravity Simulator Diagram of Mars Passage (based on 23 December orbital elements) Computing Crater Size from Projectile Diameter (H. Jay Melosh and Ross A. Beyer) Solar System Collisions (Send an asteroid or comet hurtling toward your favorite planet!) Science Friday Podcast with Don Yeomans (2007-12-28) Possible Asteroid Strike on Mars: Scientific Paydirt (2008-01-03) 2007+WD5 2007WD5 Solar System # Category:Minor planet object articles (unnumbered) Category:Discoveries by Andrea Boattini Category:Mars impact events Category:Lost minor planets 20071120 Category:Predicted impact events