 Radar image of 2023 BU by theGoldstone Solar System Radar on 29 January 2023 | |
| Discovery[1][2] | |
|---|---|
| Discovered by | Gennadiy Borisov |
| Discovery site | MARGO,Nauchnyi,Crimea |
| Discovery date | 21 January 2023 |
| Designations | |
| 2023 BU | |
| gb00553 | |
| NEO · Apollo | |
| Orbital characteristics[3] | |
| Epoch 25 February 2023 (JD 2460000.5) (Post-flyby orbit) | |
| Uncertainty parameter 1 | |
| Observation arc | 10 days (231 obs)[3] |
| Aphelion | 1.230AU |
| Perihelion | 0.9840 AU |
| 1.107 AU | |
| Eccentricity | 0.1111 |
| 1.16 yr | |
| 28.7° | |
| Inclination | 3.75° |
| 125.5° | |
| 27 January 2023 04:30[4] | |
| 355.8° | |
| Earth MOID | 0.00046 AU (69,000 km; 0.18 LD) |
| Physical characteristics | |
| 3–8 meters(CNEOS)[5] | |
| ~77 seconds[6] | |
| 29.4±0.5(JPL)[3] 29.4(MPC)[1] | |
2023 BU is anear-Earth object that passed 9,967 ± 1 km (6,193.21 ± 0.62 mi) from the centerpoint of Earth around 27 January 2023 00:29 UT.[3] SinceEarth's radius is about 6,378 km (3,963 mi), it was expected to pass approximately 3,589 ± 1 km (2,230.10 ± 0.62 mi) from the surface of Earth over the southern tip ofSouth America.[7] It passed at analtitude abovelow Earth orbit which is 2,000 km (1,200 mi) and belowgeostationary orbit which is 36,000 km (22,000 mi). The asteroid is about 3–8 meters in diameter[5] and approached Earth from the night sky. It is the fourth closest non-impacting approach known to Earth (excludingEarthgrazers) after2020 VT4,2020 QG, and2021 UA1.
The asteroid came toperihelion (closest approach to the Sun) on 27 January 2023,[4] four hours after closest approach with Earth. 2023 BU was first imaged byGennadiy Borisov atNauchnyi,Crimea, on 21 January 2023 23:53 UT,[2] about five days before closest approach. It was last observed on 31 January 2023.[1]
| Date and time of closest approach | Earth distance (AU) | Sun distance (AU) | Velocity wrt Earth (km/s) | Velocity wrt Sun (km/s) | Uncertainty region (3-sigma) | Reference |
|---|---|---|---|---|---|---|
| 2023-01-27 00:29 | 0.000067 AU (10,000 km; 0.0261 LD) | 0.985 AU (147.4 million km; 383 LD) | 9.3 | 35.2 | ± <1 km | Horizons |
The gravitational effect of the 2023 Earth approach will increase theorbital period from 359 days to an estimated 425 days.[8] It will lift the perihelion and aphelion distances. Therelatively low Earth encounter speed of 9.3 km/s (21,000 mph) is a result of a loweccentricity and Earth-like orbit.
| Parameter | Epoch | Period (p) | Aphelion (Q) | Perihelion (q) | Semi-major axis (a) | Eccentricity (e) | Inclination (i) |
|---|---|---|---|---|---|---|---|
| Units | (days) | AU | (°) | ||||
| Pre-flyby | 2022-Oct-25[8] | 358.9 | 1.05 | 0.926 | 0.988 | 0.063 | 2.35° |
| Post-flyby | 2023-Feb-25[3] | 425.4 | 1.23 | 0.984 | 1.11 | 0.111 | 3.75° |
There was no risk of anEarth impact during the 2023 Earth approach. Assuming the asteroid is at the larger size estimate of 8 meters in diameter, if it had entered the atmosphere it would not have reached the ground intact and would breakup around 30 km above the ground, thus representing only minimal threat to life.[9]
Impacts by objects 8 meters (26 ft) in diameter occur, on average, every 5 years; impacts by objects 4 meters (13 ft) in diameter happen, on average, once every year.[9] 2023 BU has a 1 in 17 million chance of impacting Earth on 20 January 2110.[10]
| JPL SBDB solution | Observation arc | Date and time of closest approach | Uncertainty region (3-sigma)[a] |
|---|---|---|---|
| JPL 1 | 1 day (25 obs) | 2023-01-26 21:17 ± 02:22[11] | ± 2,600 km[12] |
| JPL 2 | 2 days (30 obs) | 2023-01-27 00:17 ± 01:05[13] | ± 1,700 km[14] |
| JPL 3 | 3 days (42 obs) | 2023-01-27 00:28 ± 00:10[15] | ± 262 km[16] |
| JPL 4 | 3 days (39 obs) | 2023-01-27 00:26 ± 00:10[17] | ± 260 km[18] |
| JPL 5 | 4 days (65 obs) | 2023-01-27 00:28 ± 00:02[19] | ± 29 km[20] |
| JPL 6 | 4 days (61 obs) | 2023-01-27 00:28 ± 00:02[21] | ± 27 km[22] |
| JPL 9 | 5 days (121 obs) | 2023-01-27 00:29 ± <00:01 | ± 5 km[23] |
| JPL 11 | 5 days (143 obs) | 2023-01-27 00:29 ± <00:01[24] | ± 2 km[25][b] |
| JPL 12 | 6 days (166 obs) | 2023-01-27 00:29 ± <00:01[5] | ± 0.3 km[26] |
| JPL 13 | 6 days (191 obs) | 2023-01-27 00:29 ± <00:01 | ± 0.2 km[27] |
| JPL 14 | 6 days (194 obs) | 2023-01-27 00:29 ± <00:01 | ± 0.19 km[28] |
| JPL 15 | 6 days (199 obs) | 2023-01-27 00:29 ± <00:01 | ± 0.18 km[29] |
| JPL 19 | 10 days (231 obs) | 2023-01-27 00:29 ± <00:01 | ± 0.15 km[30] |
| JPL 21 | 10 days (238 obs) | 2023-01-27 00:29 ± <00:01 | ± 0.13 km[31] |
| 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 |
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