2023 BU explained

Minorplanet:	yes
2023 BU
Background:	FFC2E0
Discovered:	21 January 2023
Mpc Name:	2023 BU
Alt Names:	gb00553
Epoch:	25 February 2023 (JD 2460000.5) (Post-flyby orbit)
Uncertainty:	1
Observation Arc:	10 days (231 obs)
Perihelion:	0.9840 AU
Time Periastron:	27 January 2023 04:30
Semimajor:	1.107 AU
Eccentricity:	0.1111
Period:	1.16 yr
Inclination:	3.75°
Asc Node:	125.5°
Arg Peri:	355.8°
Moid:	0.00046AU
Mean Diameter:	3–8 meters (CNEOS)
Rotation:	~77 seconds^[1]
Abs Magnitude:	(JPL) 29.4 (MPC)

2023 BU is a near-Earth object that passed from the centerpoint of Earth around 27 January 2023 00:29 UT. Since Earth's radius is about, it was expected to pass approximately from the surface of Earth over the southern tip of South America. It passed at an altitude above low Earth orbit which is and below geostationary orbit which is . The asteroid is about 3–8 meters in diameter and approached Earth from the night sky. It is the fourth closest non-impacting approach known to Earth (excluding Earthgrazers) after,, and .

Orbital details

The asteroid came to perihelion (closest approach to the Sun) on 27 January 2023, four hours after closest approach with Earth. 2023 BU was first imaged by Gennadiy Borisov at Nauchnyi, Crimea, on 21 January 2023 23:53 UT, about five days before closest approach. It was last observed on 31 January 2023.

2023 BU closest Earth approach on 2023-Jan-27 00:29 UT! 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	6.7E-05AU	0.985AU	9.3	35.2	± <1 km	Horizons

The gravitational effect of the 2023 Earth approach will increase the orbital period from 359 days to an estimated 425 days. It will lift the perihelion and aphelion distances. The relatively low Earth encounter speed of 9.3km/s is a result of a low eccentricity and Earth-like orbit.

Orbital elements
Parameter	Epoch	Period (p)	Aphelion (Q)	Perihelion (q)	Semi-major axis (a)	Eccentricity (e)	Inclination (i)
Units		(days)	AU				(°)
Pre-flyby	2022-Oct-25	358.9	1.05	0.926	0.988	0.063	2.35°
Post-flyby	2023-Feb-25	425.4	1.23	0.984	1.11	0.111	3.75°

Impact assessment

There was no risk of an Earth 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.

Impacts by objects 8m (26feet) in diameter occur, on average, every 5 years; impacts by objects 4m (13feet) in diameter happen, on average, once every year. 2023 BU has a 1 in 17 million chance of impacting Earth on 20 January 2110.

History of 2023 BU closest approach uncertainties for the 3500–3600 km pass of Earth's surface! JPL SBDB
solution! Observation arc! Date and time of closest approach! Uncertainty region
(3-sigma)
JPL 1	1 day (25 obs)	2023-01-26 21:17 ± 02:22^[2]	± 2,600 km^[3]
JPL 2	2 days (30 obs)	2023-01-27 00:17 ± 01:05^[4]	± 1,700 km^[5]
JPL 3	3 days (42 obs)	2023-01-27 00:28 ± 00:10^[6]	± 262 km^[7]
JPL 4	3 days (39 obs)	2023-01-27 00:26 ± 00:10^[8]	± 260 km^[9]
JPL 5	4 days (65 obs)	2023-01-27 00:28 ± 00:02^[10]	± 29 km^[11]
JPL 6	4 days (61 obs)	2023-01-27 00:28 ± 00:02^[12]	± 27 km^[13]
JPL 9	5 days (121 obs)	2023-01-27 00:29 ± <00:01	± 5 km^[14]
JPL 11	5 days (143 obs)	2023-01-27 00:29 ± <00:01^[15]	± 2 km^[16]
JPL 12	6 days (166 obs)	2023-01-27 00:29 ± <00:01^[17]	± 0.3 km^[18]
JPL 13	6 days (191 obs)	2023-01-27 00:29 ± <00:01	± 0.2 km^[19]
JPL 14	6 days (194 obs)	2023-01-27 00:29 ± <00:01	± 0.19 km^[20]
JPL 15	6 days (199 obs)	2023-01-27 00:29 ± <00:01	± 0.18 km^[21]
JPL 19	10 days (231 obs)	2023-01-27 00:29 ± <00:01	± 0.15 km^[22]
JPL 21	10 days (238 obs)	2023-01-27 00:29 ± <00:01	± 0.13 km^[23]

External links

- - - Archived Scout entry

2023 BU explained

Orbital details

Impact assessment

See also

External links

Notes and References