(29075) 1950 DA
Most hazardous risk–listed near-Earth asteroid
title: "(29075) 1950 DA" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["apollo-asteroids", "discoveries-by-carl-a.-wirtanen", "potentially-hazardous-asteroids", "potential-impact-events-caused-by-near-earth-objects", "astronomical-objects-discovered-in-1950", "recovered-astronomical-objects"] description: "Most hazardous risk–listed near-Earth asteroid" topic_path: "general/apollo-asteroids" source: "https://en.wikipedia.org/wiki/(29075)_1950_DA" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Most hazardous risk–listed near-Earth asteroid ::
::data[format=table title="Infobox planet"]
| Field | Value |
|---|---|
| minorplanet | yes |
| name | (29075) 1950 DA |
| background | #FFC2E0 |
| image | 1950 DA.png |
| caption | Radar image of taken at Arecibo in March 2001, from a distance of 22 LD or 0.052 AU |
| discovery_ref | |
| discoverer | Carl A. Wirtanen |
| discovery_site | Lick Obs. |
| discovered | 23 February 1950 |
| mpc_name | (29075) 1950 DA |
| alt_names | 1950 DAObject Wirtanen |
| named_after | |
| mp_category | NEOApolloPHArisk listed |
| orbit_ref | |
| epoch | 17 October 2024 (JD 2460600.5) |
| uncertainty | 0 |
| observation_arc | 74.87 yr (27,345 d) |
| aphelion | 2.5614 AU |
| perihelion | 0.8364 AU |
| semimajor | 1.6989 AU |
| eccentricity | 0.5077 |
| period | 2.214 yr (809 d) |
| mean_anomaly | 223.31° |
| mean_motion | / day |
| inclination | 12.16° |
| asc_node | 356.59° |
| arg_peri | 224.76° |
| moid | 0.03853 AU (14.9948 LD) |
| p_orbit_ref | |
| node_rate | −35.824 |
| perihelion_rate | 13.655 |
| dimensions | |
| mean_diameter | {{Ubl |
| {{val | 1.3 |
| {{val | 1.1 |
| {{val | 1.25 |
| {{val | 2.00 |
| mass | |
| density | |
| rotation | |
| albedo | {{Ubl |
| <ref name | "Mainzer-2016" / |
| <ref name | "Rivkin-2005a" / |
| spectral_type | {{Ubl |
| S<ref name | "Dandy-2003" / |
| B–V {{ | }} |
| V–R {{ | }} |
| V–I {{ | }} |
| abs_magnitude | {{Ubl |
| 16.83<ref name | "Busch-2007b" / |
| 17.00<ref name | "Mainzer-2016" / |
| 17.28<ref name | "MPC-object" / |
| 17.2<ref name | Neodys/ |
| 17.1<ref name | "lcdb" / |
| :: |
| mass =
| density =
| rotation =
| albedo = {{Ubl
|
|
| spectral_type = {{Ubl
| S
| B–V
| V–R
| V–I
| abs_magnitude = {{Ubl
| 16.83
| 17.00
| 17.28
| 17.2
| 17.1
**** (provisional designation ****) is a risk-listed asteroid, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 1.3 km 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. , it is listed on the Sentry Risk Table with the highest cumulative Palermo scale rating of −0.93. is not assigned a Torino scale rating, because the 2880 date is over 100 years in the future. As of 11 September 2025, the odds of an Earth impact are 1 in 2,600 (0.038%).
Discovery and nomenclature
was first discovered on 23 February 1950 by Carl A. Wirtanen at Lick Observatory. Just two hours later it was recognized as .
Observations
|direction = vertical |align = left |width = 215 |image1 = 1950 DA (color).png |image2 = 1950 DA radar movie.gif |caption1 = Asteroid , Arecibo Observatory radar image (coloured version) |caption2 = Arecibo radar movie of obtained during 48 minutes (37% of a rotation) on 4 March 2001
On 5 March 2001, made a close approach to Earth at a distance of 0.05207 AU. 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 is a retrograde rotator. Optical lightcurve analysis by Lenka Šarounová and Petr Pravec shows that its rotation period is hours. Due to its short rotation period and high radar albedo, 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 ** 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.
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 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.
::data[format=table title="Position uncertainty and increasing divergence{{Cite web|url=https://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|title=Close-approach results|work=JPL Horizons|access-date=7 December 2024}} Soln.date: 2024-Dec-05 05:58:05"] | Date | JPL SBDB nominal geocentric distance (AU) | uncertainty region (1-sigma) | |---|---|---| | 2 March 2032 | 0.075752 AU | ±10 km | | 19 March 2074 | 0.095459 AU | ±30 km | | 10 March 2105 | 0.036316 AU | ±43 km | | 11 March 2136 | 0.042596 AU | ±387 km | | 8 March 2187 | 0.035224 AU | ±1717 km | | 20 March 2218 | 0.084849 AU | ±8712 km | | 18 March 2373 | 0.058991 AU | ±2508 km | | 6 March 2455 | 0.087706 AU | ±1650 km | ::
::data[format=table title="Impact probability at different times"]
| Date | JPL Solution | Impact probability |
|---|---|---|
| 5 April 2002 | ||
| 7 December 2015 | 1/8300 | |
| 29 March 2022 | 1/34000 | |
| 18 June 2024 | 1/2600 | |
| 23 January 2025 | JPL276 | 1/2600 |
| :: |
Possible Earth impact
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 from on 5 August 2150. At that distance and size, Diana will perturb enough so that the change in trajectory is notable by 2880 (730 years later). In addition, over the intervening time, 's rotation will cause its orbit to slightly change as a result of the Yarkovsky effect. If 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 does not have a significant chance of impacting Earth. , 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 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.
Notes
References
|type = 2023-10-03 last obs. |title = JPL Small-Body Database Browser: 29075 (1950 DA) |url = https://ssd.jpl.nasa.gov/tools/sbdb.cgi?sstr=2029075 |publisher = Jet Propulsion Laboratory |access-date = 18 June 2024}}
|title = 29075 (1950 DA) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=29075 |access-date = 24 February 2024}}
|type=solution: 2024-04-24; last observation: 2023-10-03; arc: 73.61 years |title=JPL Close-Approach Data: 29075 (1950 DA) |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1950%20DA&view=OPC |access-date=18 June 2024}}
|title=Asteroid 1950 DA |publisher=NASA/JPL Near-Earth Object Program Office |url=http://neo.jpl.nasa.gov/1950da/ |access-date=14 October 2011 |archive-url=https://web.archive.org/web/20110721050545/http://neo.jpl.nasa.gov/1950da/ |archive-date=21 July 2011 |url-status=dead}}
|title=(29075) 1950DA NeoDys Proper Elements |website=NeoDys Near Earth Objects Dynamic Site |url=https://newton.spacedys.com/neodys/index.php?pc=1.1.6&n=29075 |access-date=24 February 2024}}
|title=(29075) 1950DA |website=NeoDys Near Earth Objects Dynamic Site |url=https://newton.spacedys.com/neodys/index.php?pc=1.1.0&n=29075 |access-date=24 February 2024}}
|title=29075 (1950 DA) Earth Impact Risk Summary |publisher=NASA/JPL Near-Earth Object Program Office |url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=29075 |date=6 February 2022 |access-date=18 June 2024}}
|title=Sentry Risk Table |publisher=NASA/JPL Near-Earth Object Program Office |url=https://cneos.jpl.nasa.gov/sentry/ |access-date=18 June 2024}} (Use Unconstrained Settings)
|title=UT Research uncovers forces that hold asteroid together |publisher=University of Tennessee |date=13 August 2014 |url=http://tntoday.utk.edu/2014/08/13/ut-research-uncovers-forces-hold-gravitydefying-nearearth-asteroid/ |access-date=17 August 2015}}
|first1 = D. |last1 = Farnocchia |first2 = S. R. |last2 = Chesley |date = February 2014 |title = Assessment of the 2880 impact threat from Asteroid (29075) 1950 DA |journal = Icarus |volume = 229 |pages = 321–327 |bibcode = 2014Icar..229..321F |doi = 10.1016/j.icarus.2013.09.022 |arxiv = 1310.0861}}
|title = LCDB Data for (29075) |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=29075%7C |access-date = 24 February 2024}}
|display-authors = 6 |first1 = Michael W. |last1 = Busch |first2 = Jon D. |last2 = Giorgini |first3 = Steven J. |last3 = Ostro |first4 = Lance A. M. |last4 = Benner |first5 = Raymond F. |last5 = Jurgens |first6 = Randy |last6 = Rose |first7 = Michael D. |last7 = Hicks |first8 = Petr |last8 = Pravec |first9 = Peter |last9 = Kusnirak |first10 = Michael J. |last10 = Ireland |first11 = Daniel J. |last11 = Scheeres |first12 = Stephen B. |last12 = Broschart |first13 = Christopher |last13 = Magri |first14 = Michael C. |last14 = Nolan |first15 = Alice A. |last15 = Hine |first16 = Jean-Luc |last16 = Margot |date = October 2007 |title = Physical modeling of near-Earth Asteroid (29075) 1950 DA |url = https://echo.jpl.nasa.gov/asteroids/29075_1950DA/busch.etal.2007.1950da.pdf |journal = Icarus |volume = 190 |issue = 2 |pages = 608–621 |bibcode = 2007Icar..190..608B |doi = 10.1016/j.icarus.2007.03.032 |access-date = 24 February 2024}}
|display-authors = 6 |first1 = J. D. |last1 = Giorgini |first2 = S. J. |last2 = Ostro |first3 = L. A. M. |last3 = Benner |first4 = P. W. |last4 = Chodas |first5 = S. R. |last5 = Chesley |first6 = R. S. |last6 = Hudson |first7 = M. C. |last7 = Nolan |first8 = A. R. |last8 = Klemola |first9 = E. M. |last9 = Standish |first10 = R. F. |last10 = Jurgens |first11 = R. |last11 = Rose |first12 = A. B. |last12 = Chamberlin |first13 = D. K. |last13 = Yeomans |first14 = J.-L. |last14 = Margot |date = April 2002 |title = Asteroid 1950 DA's Encounter with Earth in 2880: Physical Limits of Collision Probability Prediction |url = https://cneos.jpl.nasa.gov/doc/1950da/1950da_published.pdf |journal = Science |volume = 296 |issue = 5565 |pages = 132–136 |bibcode = 2002Sci...296..132G |doi = 10.1126/science.1068191 |pmid = 11935024}}
|display-authors = 6 |first1 = A. K. |last1 = Mainzer |first2 = J. M. |last2 = Bauer |first3 = R. M. |last3 = Cutri |first4 = T. |last4 = Grav |first5 = E. A. |last5 = Kramer |first6 = J. R. |last6 = Masiero |first7 = C. R. |last7 = Nugent |first8 = S. M. |last8 = Sonnett |first9 = R. A. |last9 = Stevenson |first10 = E. L. |last10 = Wright |date = June 2016 |title = NEOWISE Diameters and Albedos V1.0 |url = https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_COMPIL_5_NEOWISEDIAM_V1_0/data/neowise_mainbelt.tab |journal = NASA Planetary Data System |volume = 247 |pages = EAR-A-COMPIL-5-NEOWISEDIAM-V1.0 |bibcode = 2016PDSS..247.....M |access-date= 5 July 2018}}
|first1 = C. L. |last1 = Dandy |first2 = A. |last2 = Fitzsimmons |first3 = S. J. |last3 = Collander-Brown |date = June 2003 |title = Optical colors of 56 near-Earth objects: trends with size and orbit |journal = Icarus |volume = 163 |issue = 2 |pages = 363–373 |bibcode = 2003Icar..163..363D |doi = 10.1016/S0019-1035(03)00087-3}}
|first1 = A. S. |last1 = Rivkin |first2 = R. P. |last2 = Binzel |first3 = S. J. |last3 = Bus |date = May 2005 |title = Constraining near-Earth object albedos using near-infrared spectroscopy |journal = Icarus |volume = 175 |issue = 1 |pages = 175–180 |bibcode = 2005Icar..175..175R |doi = 10.1016/j.icarus.2004.11.005}}
|first1 = Ben |last1 = Rozitis |first2 = Eric |last2 = MacLennan |first3 = Joshua P. |last3 = Emery |date = 13 August 2014 |title = Cohesive forces prevent the rotational breakup of rubble-pile asteroid (29075) 1950 DA |journal = Nature |volume = 512 |issue = 7513 |pages = 174–176 |doi = 10.1038/nature13632 |pmid = 25119234 |bibcode = 2014Natur.512..174R|url = https://oro.open.ac.uk/44912/1/BR_1950DA_accepted.pdf
|title = IAUC 1258, 1259, 1262: Rapidly Moving Object Wirtanen [1950 DA] |url = http://www.cbat.eps.harvard.edu/indexto_iauc8000.html |year = 1950 |work = IAU Circulars |publisher = Central Bureau for Astronomical Telegrams |access-date = 10 February 2025}}
References
- (29 March 2022). "Impact threat analysis update completed for 1950 DA". European Space Agency.
- (4 January 2001). "MPEC 2001-A22 : 2000 YK66". Minor Planet Center.
- (4 January 2001). "MPEC 2001-A26 : 1950 DA = 2000 YK66". Minor Planet Center.
- "Close-approach results". JPL Horizons.
- (January 2015). "Star catalog position and proper motion corrections in asteroid astrometry". Icarus.
- "Sentry: Earth Impact Monitoring".
- (1 June 2024). "Asteroid Orbit Determination Using Gaia FPR: Statistical Analysis". The Astronomical Journal.
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