(29075) 1950 DA

Most hazardous risk–listed near-Earth asteroid March 2020 yes (29075) 1950 DA #FFC2E0 1950 DA.png Radar image of 1950 DA taken at Arecibo in March 2001, from a distance of 22 LD or 0.052 AU Carl A. Wirtanen Lick Obs. 23 February 1950 (29075) 1950 DA 2000 YK 66Object Wirtanen NEOApolloPHArisk listed 17 October 2024 (JD 2460600.5) 0 74.87 yr (27,345 d) 2.5614 AU 0.8364 AU 1.6989 AU 0.5077 2.214 yr (809 d) 223.31° 0.4451 ms / day 12.16° 356.59° 224.76° 0.03853 AU (14.9948 LD) −35.824 13.655 1.39 x 1.46 x 1.07 km 1.3 km 1.1 km 1.25 0.12 km 2.00 0.20 km >4 12 kgestimate >3.5 g/cm3 2.12160 0.00004 h 0.070 0.25 S B–V 0.862 0.077 V–R 0.494 0.069 V–I 0.816 0.067 16.83 17.00 17.28 17.2 17.1 (29075) 1950 DA is a risk-listed asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.3 km off us in diameter. It once had the highest known probability of impacting Earth. In 2002, it had the highest Palermo scale rating with a value of 0.17 and a probability of 1 in 306 (0.33%) for a possible collision in 2880. Since that time, the estimated risk has been updated several times. In December 2015, the odds of an Earth impact were revised to 1 in 8,300 (0.012%) with a Palermo scale rating of −1.42. 2025 10, it is listed on the Sentry Risk Table with the highest cumulative Palermo scale rating of −0.93.https://neo.ssa.esa.int/-/impact-threat-analysis-update-completed-for-1950-da Impact threat analysis update completed for 1950 DA 29 March 2022 European Space Agency 1950 DA is not assigned a Torino scale rating, because the 2880 date is over 100 years in the future. As of 25 October 2025, the odds of an Earth impact are 1 in 2,600 (0.038%). Discovery and nomenclature 1950 DA was first discovered on 23 February 1950 by Carl A. Wirtanen at Lick Observatory. It was observed for seventeen days and then lost because this short observation arc resulted in large uncertainties in Wirtanen's orbital solution. On 31 December 2000, it was recovered at Lowell Observatory and was announced as 2000 YK 66 on 4 January 2001.https://minorplanetcenter.net/mpec/K01/K01A22.html MPEC 2001-A22 : 2000 YK66 Minor Planet Center 4 January 2001 23 February 2018 Just two hours later it was recognized as 1950 DA.https://minorplanetcenter.net/mpec/K01/K01A26.html MPEC 2001-A26 : 1950 DA = 2000 YK66 Minor Planet Center 4 January 2001 23 February 2018 Observations vertical left 215 1950 DA (color).png 1950 DA radar movie.gif Asteroid 1950 DA, Arecibo Observatory radar image (coloured version) Arecibo radar movie of 1950 DA obtained during 48 minutes (37% of a rotation) on 4 March 2001 On 5 March 2001, 1950 DA made a close approach to Earth at a distance of 0.05207 AU e6km e6mi LD unit on. It was studied by radar at the Goldstone and Arecibo observatories from March 3 to 7, 2001. The studies showed that the asteroid has a mean diameter of 1.1 km, assuming that 1950 DA is a retrograde rotator. Optical lightcurve analysis by Lenka Šarounová and Petr Pravec shows that its rotation period is 2.1216 0.0001 hours. Due to its short rotation period and high radar albedo, 1950 DA is thought to be fairly dense (more than 3.5 g/cm3, assuming that it has no internal strength) and likely composed of nickel–iron. In August 2014, scientists from the University of Tennessee determined that 1950 DA is a rubble pile rotating faster than the breakup limit for its density, implying the asteroid is held together by van der Waals forces rather than gravity. 1950 DA made distant approaches to Earth on 20 May 2012, 5 February 2021 and 5 February 2023. However, at these times it was a quarter to half an AU away from Earth, preventing more useful astrometrics and timing that occurs when an object is closer to Earth. The next close approach that presents a good opportunity to observe the asteroid will be on 2 March 2032, when it will be 0.076 AU e6km unit off from Earth. The following table lists the approaches closer than 0.1 AU until the year 2500. By 2136 the close approach solutions are becoming notably more divergent.June 2024 +Position uncertainty and increasing divergencehttps://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%2729075%27&EPHEM_TYPE=%27APPROACH%27&CA_TABLE_TYPE=%27EXTENDED%27&CALIM_SB=%270.10%27&START_TIME=%272020-01-01%27&STOP_TIME=%272500-01-01%27 Close-approach results JPL Horizons 7 December 2024 Soln.date: 2024-Dec-05 05:58:05 Date JPL SBDBnominal geocentricdistance (AU) uncertaintyregion(1-sigma) 2 March 2032 0.075752 AU km unit ±10 km19 March 2074 0.095459 AU km unit ±30 km10 March 2105 0.036316 AU km unit ±43 km11 March 2136 0.042596 AU km unit ±387 km 8 March 2187 0.035224 AU km unit ±1717 km20 March 2218 0.084849 AU km unit ±8712 km18 March 2373 0.058991 AU km unit ±2508 km 6 March 2455 0.087706 AU km unit ±1650 km +Impact probability at different times Date JPL Solution Impact probability 5 April 2002 1/3067 December 2015 Farnocchia D. Chesley S.R. Chamberlin A.B. Tholen D.J. Star catalog position and proper motion corrections in asteroid astrometry Icarus January 2015 245 94–111 10.1016/j.icarus.2014.07.033 1407.8317 2015Icar..245...94F 1/830029 March 2022 https://cneos.jpl.nasa.gov/sentry/notes.html Sentry: Earth Impact Monitoring 1/3400018 June 2024 Fuentes-Muñoz Oscar Farnocchia Davide Naidu Shantanu P. Park Ryan S. Asteroid Orbit Determination Using Gaia FPR: Statistical Analysis The Astronomical Journal 1 June 2024 167 6 290 10.3847/1538-3881/ad4291 free 2024AJ....167..290F 1/260023 January 2025 JPL276 1/2600 Possible Earth impact 1950 DA has one of the best-determined asteroid orbital solutions. This is due to a combination of: an orbit moderately inclined (12 degrees) to the ecliptic plane (reducing in-plane perturbations); high-precision radar astrometry, which provides its distance and is complementary to the measurements of angular positions; a 74-year observation arc; an uncertainty region controlled by resonance. Main-belt asteroid 78 Diana (~125 km in diameter) will pass about 0.003 AU km mi on on from 1950 DA on 5 August 2150. At that distance and size, Diana will perturb 1950 DA enough so that the change in trajectory is notable by 2880 (730 years later). In addition, over the intervening time, 1950 DA's rotation will cause its orbit to slightly change as a result of the Yarkovsky effect. If 1950 DA continues on its present orbit, it may approach Earth on 16 March 2880, though the mean trajectory passes many millions of kilometres from Earth, so 1950 DA does not have a significant chance of impacting Earth. 2025 9, according to the latest solution dated 11 September 2025, the probability of an impact in 2880 is 1 in 2,600 (0.038%). The energy released by a collision with an object the size of 1950 DA would cause major effects on the climate and biosphere, which would be devastating to human civilization. The discovery of the potential impact heightened interest in asteroid deflection strategies.April 2025 See also List of exceptional asteroids Landmark asteroids Asteroid impact prediction Earth-grazing fireball List of asteroid close approaches to Earth Notes estimate A reported volume of 1.14 km3 × density of 3.5 g/cm3 yields a mass (m = d × v) of 3.99e12 kg References 2023-10-03 last obs. JPL Small-Body Database Browser: 29075 (1950 DA) https://ssd.jpl.nasa.gov/tools/sbdb.cgi?sstr=2029075 Jet Propulsion Laboratory 18 June 2024 29075 (1950 DA) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=29075 24 February 2024 solution: 2024-04-24; last observation: 2023-10-03; arc: 73.61 years JPL Close-Approach Data: 29075 (1950 DA) https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1950%20DA&view=OPC 18 June 2024 Asteroid 1950 DA NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/1950da/ 14 October 2011 https://web.archive.org/web/20110721050545/http://neo.jpl.nasa.gov/1950da/ 21 July 2011 dead (29075) 1950DA NeoDys Proper Elements NeoDys Near Earth Objects Dynamic Site https://newton.spacedys.com/neodys/index.php?pc=1.1.6&n=29075 24 February 2024 (29075) 1950DA NeoDys Near Earth Objects Dynamic Site https://newton.spacedys.com/neodys/index.php?pc=1.1.0&n=29075 24 February 2024 29075 (1950 DA) Earth Impact Risk Summary NASA/JPL Near-Earth Object Program Office https://cneos.jpl.nasa.gov/sentry/details.html#?des=29075 6 February 2022 18 June 2024 Sentry Risk Table NASA/JPL Near-Earth Object Program Office https://cneos.jpl.nasa.gov/sentry/ 18 June 2024 (Use Unconstrained Settings) UT Research uncovers forces that hold asteroid together University of Tennessee 13 August 2014 http://tntoday.utk.edu/2014/08/13/ut-research-uncovers-forces-hold-gravitydefying-nearearth-asteroid/ 17 August 2015 https://web.archive.org/web/20170409205922/http://tntoday.utk.edu/2014/08/13/ut-research-uncovers-forces-hold-gravitydefying-nearearth-asteroid/ 9 April 2017 dead D. Farnocchia S. R. Chesley February 2014 Assessment of the 2880 impact threat from Asteroid (29075) 1950 DA Icarus 229 321–327 2014Icar..229..321F 10.1016/j.icarus.2013.09.022 1310.0861 29075 24 February 2024 6 Michael W. Busch Jon D. Giorgini Steven J. Ostro Lance A. M. Benner Raymond F. Jurgens Randy Rose Michael D. Hicks Petr Pravec Peter Kusnirak Michael J. Ireland Daniel J. Scheeres Stephen B. Broschart Christopher Magri Michael C. Nolan Alice A. Hine Jean-Luc Margot October 2007 Physical modeling of near-Earth Asteroid (29075) 1950 DA https://echo.jpl.nasa.gov/asteroids/29075_1950DA/busch.etal.2007.1950da.pdf Icarus 190 2 608–621 2007Icar..190..608B 10.1016/j.icarus.2007.03.032 24 February 2024 6 J. D. Giorgini S. J. Ostro L. A. M. Benner P. W. Chodas S. R. Chesley R. S. Hudson M. C. Nolan A. R. Klemola E. M. Standish R. F. Jurgens R. Rose A. B. Chamberlin D. K. Yeomans J.-L. Margot April 2002 Asteroid 1950 DA's Encounter with Earth in 2880: Physical Limits of Collision Probability Prediction https://cneos.jpl.nasa.gov/doc/1950da/1950da_published.pdf Science 296 5565 132–136 2002Sci...296..132G 10.1126/science.1068191 11935024 6 A. K. Mainzer J. M. Bauer R. M. Cutri T. Grav E. A. Kramer J. R. Masiero C. R. Nugent S. M. Sonnett R. A. Stevenson E. L. Wright June 2016 NEOWISE Diameters and Albedos V1.0 https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_COMPIL_5_NEOWISEDIAM_V1_0/data/neowise_mainbelt.tab NASA Planetary Data System 247 EAR-A-COMPIL-5-NEOWISEDIAM-V1.0 2016PDSS..247.....M 5 July 2018 C. L. Dandy A. Fitzsimmons S. J. Collander-Brown June 2003 Optical colors of 56 near-Earth objects: trends with size and orbit Icarus 163 2 363–373 2003Icar..163..363D 10.1016/S0019-1035(03)00087-3 A. S. Rivkin R. P. Binzel S. J. Bus May 2005 Constraining near-Earth object albedos using near-infrared spectroscopy Icarus 175 1 175–180 2005Icar..175..175R 10.1016/j.icarus.2004.11.005 Ben Rozitis Eric MacLennan Joshua P. Emery 13 August 2014 Cohesive forces prevent the rotational breakup of rubble-pile asteroid (29075) 1950 DA Nature 512 7513 174–176 10.1038/nature13632 25119234 2014Natur.512..174R https://oro.open.ac.uk/44912/1/BR_1950DA_accepted.pdf IAUC 1258, 1259, 1262: Rapidly Moving Object Wirtanen [1950 DA] http://www.cbat.eps.harvard.edu/indexto_iauc8000.html 1950 IAU Circulars Central Bureau for Astronomical Telegrams 10 February 2025 External links MPEC 2001-A26 : 1950 DA = 2000 YK66 (K00Y66K). MPC 4 January 2001 3D model Rotating model of the asteroid (preferred rotation model is retrograde, NeoDys) Asteroid Lightcurve Database (LCDB), query form (info https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html 16 December 2017 ) Asteroids and comets rotation curves, CdR https://web.archive.org/web/20160729213840/http://obswww.unige.ch/~behrend/page_cou.html 29 July 2016 Observatoire de Genève, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (25001)-(30000) Minor Planet Center 29075 29075 29075 Astronomy Stars Spaceflight Outer space Solar System 029075 Category:Discoveries by Carl A. Wirtanen 029075 029075 19500222 029075