1991 BA

Small risk–listed near-Earth asteroid February 2018 yes 1991 BA #FFC2E0 18 January 1991 Spacewatch Kitt Peak Obs. 1991 BA ApolloNEO 18 January 1991 (JD 2448274.5) 9 4.6 hours 3.662 0.430 AU 0.7153 0.0122 AU 2.189 0.257 AU 0.6732 0.0440 3.24 0.57 yr (1183 208 commas days) 346.836 2.609 ° 0.30434867 ms / day 1.938 0.104 ° 118.880 0.012 ° 70.688 0.260 ° 0.0003 AU0.1 LD 5–10 m 28.6 1991 BA is a sub-kilometer asteroid, classified as near-Earth object of the Apollo group that was first observed by Spacewatch on 18 January 1991, and passed within 160,000 km mi on of Earth. This is a little less than half the distance to the Moon. With a 5-hour observation arc the asteroid has a poorly constrained orbit and is considered lost. It could be a member of the Beta Taurids.Peter Jenniskens Meteor Showers and their Parent Comets pg 463 fig 25.7 Description 1991 BA is approximately 5 to 10 m ft us in diameter and is listed on the Sentry Risk Table. It follows a highly eccentric (0.68), low-inclination (2.0°) orbit of 3.3 years duration, ranging between 0.71 and 3.7 AU from the Sun. 1991 BA was, at the time of its discovery, the smallest and closest confirmed asteroid outside of Earth's atmosphere. 1991 BA is too faint to be observed except during close approaches to Earth and is considered lost. Possible impact The asteroid has a very short 5-hour observation arc that makes future predictions of its position unreliable. Virtual clones of the asteroid that fit the uncertainty region in the known trajectory use to show a 1 in 290,000 chance that the asteroid could impact Earth on 2023 January 18. It is estimated that an impact would produce an upper atmosphere air burst equivalent to 16 kt TNT, roughly equal to Nagasaki's Fat Man. The asteroid would appear as a bright fireball and fragment in the air burst into smaller pieces that would hit the ground at terminal velocity producing a meteorite strewn field. Impacts of objects this size are estimated to occur approximately once a year.Asteroid Fast Facts NASA https://web.archive.org/web/20230526185348/https://www.nasa.gov/mission_pages/asteroids/overview/fastfacts.html 2023-05-26 live https://www.nasa.gov/mission_pages/asteroids/overview/fastfacts.html Asteroid 2008 TC 3 was an object of similar size that was discovered less than a day before its impact on Earth on October 7, 2008, and produced a fireball and meteorite strewn field in the Sudan. The 18 January 2023 virtual impactor did not occur. +Virtual impactor Date Impactprobability(1 in) JPL Horizonsnominal geocentricdistance (AU) NEODySnominal geocentricdistance (AU) MPCnominal geocentricdistance (AU) Find_Orbnominal geocentricdistance (AU) uncertaintyregion(3-sigma)2023-01-18 290000 3.9 AU e6km unit on 3.9 AU e6km unit 2.4 AU e6km unit 2.8 AU e6km unit ± 841 million km There is a 1 in a million chance of impacting Earth on 19 January 2114. References 1991-01-18 last obs. JPL Small-Body Database Browser: (1991 BA) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3092104 Jet Propulsion Laboratory 2 August 2017 1991 BA Minor Planet Center http://www.minorplanetcenter.net/db_search/show_object?object_id=1991+BA 2 August 2017 last observation: 1991-01-18; arc: 1 day; uncertainty: 9 JPL Close-Approach Data: (1991 BA) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1991BA;cad=1#cad 2012-03-20 Earth Impact Risk Summary: 1991 BA NASA/JPL Near-Earth Object Program Office https://cneos.jpl.nasa.gov/sentry/details.html#?des=1991%20BA https://web.archive.org/web/20110817035909/http://neo.jpl.nasa.gov/risk/1991ba.html 2011-08-17 live 2012-03-10 Scotti J. V. James V. Scotti Rabinowitz, D. L. David L. Rabinowitz Marsden, B. G. Brian G. Marsden Near miss of the Earth by a small asteroid Nature 354 287–289 1991 6351 10.1038/354287a0 1991Natur.354..287S Horizons Batch for 2023-01-18 Virtual Impactor JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271991+BA%27&START_TIME=%272023-01-18%27&STOP_TIME=%272023-01-19%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27 https://web.archive.org/web/20221109195513/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271991+BA%27&START_TIME=%272023-01-18%27&STOP_TIME=%272023-01-19%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27 2022-11-09 live 2021-11-09 RNG_3sigma = uncertainty range in km. (JPL#12/Soln.date: 2021-Apr-15 generates RNG_3sigma = 841846388 km for 2023-Jan-18.) 2009JF1 Ephemerides for 18 January 2023 NEODyS (Near Earth Objects Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1991BA&oc=500&y0=2023&m0=01&d0=18&y1=2023&m1=01&d1=18&ti=1.0&tiu=days https://web.archive.org/web/20221109200240/https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1991BA&oc=500&y0=2023&m0=01&d0=18&y1=2023&m1=01&d1=18&ti=1.0&tiu=days 2022-11-09 live 2022-11-09 MPC Ephemeris Service IAU Minor Planet Center https://minorplanetcenter.net//iau/MPEph/MPEph.html 2022-11-09 Find_Orb for 2023-01-18 Project Pluto https://www.projectpluto.com/cgi-bin/fo/fo_serve.cgi?obj_name=1991+BA&year=2022-01-18&n_steps=1&stepsize=1 https://web.archive.org/web/20221109200931/https://www.projectpluto.com/cgi-bin/fo/fo_serve.cgi?obj_name=1991+BA&year=2022-01-18&n_steps=1&stepsize=1 2022-11-09 live 2021-11-09 External links IAUC 5172: 1991 BA; 4U 0115+63; 1990c – (Central Bureau for Astronomical Telegrams 1991 January 21) 1991+BA 1991BA # Category:Minor planet object articles (unnumbered) 19910118 Category:Lost minor planets Category:Potential impact events caused by near-Earth objects 19910118