![]() Orbit of 2021 UA1 | |
Discovery[1] | |
---|---|
Discovered by | Catalina Sky Survey |
Discovery date | 25 October 2021 |
Designations | |
2021 UA1 | |
| |
Orbital characteristics[3] | |
Epoch 2021-Jul-01 (JD 2459396.5) | |
Uncertainty parameter 6 | |
Observation arc | 0.9 days[2] |
Aphelion | 1.35 AU (Q) |
Perihelion | 0.6139 AU (q) |
0.98 AU (a) | |
Eccentricity | 0.3750 (e) |
0.97 years | |
312.8° (M) | |
Inclination | 10.19° (i) |
211.6° (Ω) | |
66.27° (ω) | |
Earth MOID | 0.000064 AU (9,600 km) |
Jupiter MOID | 3.7 AU (550,000,000 km) |
Physical characteristics | |
Dimensions |
|
31.8[3][4] | |
2021 UA1 is a small (~2 meter) near-Earth object that passed about 3047 km from the surface of Earth while passing over Antarctica on 25 October 2021 around 03:07 UT.[5][a] Given the small size of the asteroid it only reached the brightness of Pluto at around apparent magnitude 14.[5] Since it approached from the direction of the Sun, it was not discovered until 4 hours after closest approach.[1]
Asteroid | Date | Distance from surface of Earth |
Uncertainty in approach distance |
Observation arc | Reference |
---|---|---|---|---|---|
2020 VT4 | 2020-11-13 17:21 | 368 km | ±11 km | 5 days (34 obs) | data |
2020 QG | 2020-08-16 04:09 | 2939 km | ±11 km | 2 days (35 obs) | data |
2021 UA1 | 2021-10-25 03:07 | 3049 km | ±10 km | 1 day (22 obs) | data |
2023 BU | 2023-01-27 00:29 | 3589 km | ±<1 km | 10 days (231 obs) | data |
2011 CQ1 | 2011-02-04 19:39 | 5474 km | ±5 km | 1 day (35 obs) | data |
2019 UN13 | 2019-10-31 14:45 | 6235 km | ±189 km | 1 day (16 obs) | data |
2008 TS26 | 2008-10-09 03:30 | 6260 km | ±970 km | 1 day (19 obs) | data |
2004 FU162 | 2004-03-31 15:35 | 6535 km | ±13000 km | 1 day (4 obs) | data |
The 2021 Earth approach lifted the orbit and increased the orbital period from 356 days to 413 days.[6] This changed it from an Aten asteroid to an Apollo asteroid.
Parameter | Epoch | Period (p) |
Aphelion (Q) |
Perihelion (q) |
Semi-major axis (a) |
Eccentricity (e) |
Inclination (i) |
---|---|---|---|---|---|---|---|
Units | (days) | AU | (°) | ||||
Pre-flyby | 2021-Jul-01[3] | 355.6 | 1.351 | 0.614 | 0.982 | 0.3750 | 10.19° |
Post-flyby | 2022-Jan-01[6] | 413.1 | 1.525 | 0.646 | 1.086 | 0.4046 | 0.006° |
MPEC2021-U95
was invoked but never defined (see the help page).sentry
was invoked but never defined (see the help page).jpldata
was invoked but never defined (see the help page).MPC-object
was invoked but never defined (see the help page).Horizons2021
was invoked but never defined (see the help page).Horizons-epoch
was invoked but never defined (see the help page).
Cite error: There are <ref group=lower-alpha>
tags or {{efn}}
templates on this page, but the references will not show without a {{reflist|group=lower-alpha}}
template or {{notelist}}
template (see the help page).