1979 XB

Lost near-Earth asteroid August 2019 yes 1979 XB #FFC2E0 Siding Spring Obs. Siding Spring Obs. 11 December 1979(first observed only) 1979 XB LostApolloNEOPHArisk listed 14 December 1979 (JD 2444221.5) 9 3.9 days 3.8 0.7 AU (Q) 0.65 0.01 AU (q) 2.2 0.4 AU (a) 0.7 0.06 (e) 3.3 0.9 years 346 4 ° (M) 0.2963 ms / day 24.7 1.6 ° (i) 86 0.12 ° (Ω) 75.6 0.7 ° (ω) 0.02 AU LD on? 660 m (est.)500–1000 meters 18.6? 1979 XB is a lost asteroid with a short observation arc of 3.9 days that cannot be recovered with targeted observations and awaits serendipitous survey observations. It is classified as a near-Earth object and potentially hazardous asteroid of the Apollo group and is estimated to be 660 m ft off us 2 in diameter. The unnumbered minor planet has a poorly constrained orbit and has not been observed in 1979 12 11 years. It has been listed on the Sentry Risk Table since the list started in 2002. 2025 2 11, With a cumulative Palermo scale rating of −2.70, the poorly known orbit and assumed size place 1979 XB fourth on an unconstrained listing of the Sentry Risk Table. 1979 XB was first observed on 11 December 1979 by astronomers at the Siding Spring Observatory, Australia, when the asteroid was estimated to be 0.09 +/- 0.02 AU e6km unit in from Earth and had a solar elongation of 127°. The object has never been confirmed by a second observatory. The uncertainty region for this asteroid is now hundreds of millions of kilometers long. Orbit-fit With a short 4-day observation arc, the trajectory is poorly constrained and the uncertainties fit numerous different orbits. The perihelion point (closest approach to the Sun) is better known than the aphelion point (furthest distance from the Sun). Due to the uncertainty, the orbital period ranges from 2.4 to 4.2 years. +Epoch 2019 orbit fits for 1979 XB Source Aphelion Orbital period Earth MOIDMPC 3.8 AU e6km unit 3.31 years days 0.02 AU e6km unitNEODyS 4.5 AU e6km unit 1496 days years flip 0.001 AU e3km unit 2024 Around mid-December 2024 the asteroid had about a 0.05% chance of making an Earth approach within 0.1 AU. If it did make an Earth approach, it did not come any closer than 0.005 AU km mi on. The nominal JPL Horizons December 2024 Earth distance is 4 AU km mi on with an uncertainty of more than a billion km. 2056 virtual impactor JPL Horizons suggests that the closest approach the asteroid will make to Earth in 2056 is a distant 1.2 AU km mi on on 4 August 2056. NEODyS expects the closest Earth approach to be an even more distant 3.1 AU km mi on on 2 October 2056. With a short 4-day observation arc, 2025 2 y, the Sentry Risk Table shows an estimated 1 in 5.3 million chance of the asteroid impacting Earth on 12 December 2056. The nominal JPL Horizons 12 December 2056 Earth distance is 3 AU km mi on with a 3-sigma uncertainty of ±13 billion km. NEODyS lists the nominal 12 December 2056 Earth distance as 3.6 AU km mi on. The Sentry Risk Table also lists potential impacts in 2086, 2102 and 2113. +Virtual impactors Date Sentry impactprobability(1 in) JPL Horizonsnominal geocentricdistance & uncertainty region (AU) NEODySnominal geocentricdistance (AU)2056-12-12 5.3 million 3.0 AU e6km unit ±89.6 AU e6km unit 3.2 AU e6km unit2086-12-16 9.1 million 3.3 AU e6km unit ±64.9 AU e6km unit 3.3 AU e6km unit2102-12-16 8.3 billion 0.4 AU e6km unit ±76.8 AU e6km unit 0.6 AU e6km unit2113-12-14 1.8 million 3.9 AU e6km unit ±32.0 AU e6km unit 3.9 AU e6km unit See also 2007 FT 3 List of unnumbered minor planets 1970–1979 References 1979-12-15 last obs. JPL Small-Body Database Browser: (1979 XB) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3012393 Jet Propulsion Laboratory 31 August 2019 (Wayback Machine 2018-01-30) 1979 XB Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=1979+XB 31 August 2019 Sentry: Earth Impact Monitoring NASA/JPL Center for NEO Studies https://cneos.jpl.nasa.gov/sentry/ 2025-02-11 (Use Unconstrained Settings to reveal 1979 XB with impact probability below 1e-7) Earth Impact Risk Summary: 1979 XB NASA/JPL CNEOS https://cneos.jpl.nasa.gov/sentry/details.html#?des=1979%20XB 2025-02-11 live https://web.archive.org/web/20250210173009/https://cneos.jpl.nasa.gov/sentry/details.html#?des=1979%20XB 2025-02-10 1979XB Close Approaches NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com//neodys/index.php?pc=1.1.8&n=1979XB https://archive.today/20190830150644/https://newton.spacedys.com//neodys/index.php?pc=1.1.8&n=1979XB 30 August 2019 live 2019-08-30 1979XB Orbital Information NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com//neodys/index.php?pc=1.1.1&n=1979XB https://web.archive.org/web/20190831213944/https://newton.spacedys.com//neodys/index.php?pc=1.1.1&n=1979XB 2019-08-31 live 2019-08-31 NEODyS-2 Risk List NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=4.1 https://web.archive.org/web/20181120220955/https://newton.spacedys.com/neodys/index.php?pc=4.1 2018-11-20 live 2021-03-08 Go to JPL Horizons. Table Settings: only need "20. Observer range & range-rate" AND "39. Range & range-rate 3-sigmas".RNG_3sigma = uncertainty range in km. (Soln.date: 2017-Apr-06 generates RNG_3sigma = 1.211291E9 for 2024-Dec-08) Horizons Batch for 2056-12-12 Virtual Impactor JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271979+XB%27&START_TIME=%272056-12-12%27&STOP_TIME=%272056-12-13%27&STEP_SIZE=%272%20days%27&QUANTITIES=%2720,39%27 2025-02-11 Horizons Batch for 2086-12-16 Virtual Impactor JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271979+XB%27&START_TIME=%272086-12-16%27&STOP_TIME=%272086-12-17%27&STEP_SIZE=%272%20days%27&QUANTITIES=%2720,39%27 2025-02-11 Horizons Batch for 2102-12-16 Virtual Impactor JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271979+XB%27&START_TIME=%272102-12-16%27&STOP_TIME=%272102-12-17%27&STEP_SIZE=%272%20days%27&QUANTITIES=%2720,39%27 2025-02-11 Horizons Batch for 2113-12-14 Virtual Impactor JPL Horizons https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271979+XB%27&START_TIME=%272113-12-14%27&STOP_TIME=%272113-12-15%27&STEP_SIZE=%272%20days%27&QUANTITIES=%2720,39%27 2025-02-11 1979XB Ephemerides for 2056 NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1979XB&oc=500&y0=2056&m0=1&d0=1&h0=0&mi0=0&y1=2056&m1=12&d1=31&h1=0&mi1=0&ti=1.0&tiu=days 2025-02-11 1979XB Ephemerides for 2086 NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1979XB&oc=500&y0=2086&m0=1&d0=1&h0=0&mi0=0&y1=2086&m1=12&d1=31&h1=0&mi1=0&ti=1.0&tiu=days 2025-02-11 1979XB Ephemerides for 2102 NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1979XB&oc=500&y0=2102&m0=1&d0=1&h0=0&mi0=0&y1=2102&m1=12&d1=31&h1=0&mi1=0&ti=1.0&tiu=days 2025-02-11 1979XB Ephemerides for 2113-12-14 NEODyS (Near Earth Objects – Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1979XB&oc=500&y0=2113&m0=12&d0=13&h0=0&mi0=0&y1=2113&m1=12&d1=15&h1=0&mi1=0&ti=1.0&tiu=days 2025-02-11 External links 1979+XB 1979XB 3012393 # Category:Minor planet object articles (unnumbered) # Category:Lost minor planets # Category:Potential impact events caused by near-Earth objects 19791211