Asteroids

2021BW1 help

Last update: 2026-03-12 13:01 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Aten

Perihelion (q)

0.719

Aphelion (Q)

1.050

Eccentricity (e)

0.187

Inclination (i)

0.9

deg

Orbit period (P)

303.7

Earth MOID

0.00154

U parameter

0.9

Next Earth close approach

Date

2031-03-20

Nominal distance (from Earth center)

0.02172

3249326

Maximum Brightness

21.9

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

26.4

mag

Diameter

14 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-01-16

Observatory

Pan-STARRS 1, Haleakala

ORBIT VISUALISATION TOOLS

External links

Proper elements

Epoch

Near present day

Near middle of observation arc

Orbit properties

Epoch
Semimajor Axis
Eccentricity (e)
Inclination (i)
Long. of Ascending Node (Ω)
Arg. of Perihelion (ω)
Mean Anomaly (M)
Perihelion distance
Aphelion distance
Asc. Node-Earth Sep.
Desc. Node-Earth Sep.
MOID
Orbit Period
U parameter

Value

1-sigma variation

Unit

Epoch

Value

61200.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

0.884307

1-sigma variation

8.785E-9

Unit

Eccentricity (e)

Value

0.187221

1-sigma variation

8.455E-8

Unit

Inclination (i)

Value

0.9100

1-sigma variation

2.231E-6

Unit

Long. of Ascending Node (Ω)

Value

98.7129

1-sigma variation

0.0001

Unit

Arg. of Perihelion (ω)

Value

219.0271

1-sigma variation

0.0001

Unit

Mean Anomaly (M)

Value

330.04277

1-sigma variation

0.00006

Unit

Perihelion distance

Value

0.718747

1-sigma variation

Unit

Aphelion distance

Value

1.049868

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.014558

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.271574

1-sigma variation

Unit

MOID

Value

0.001536

1-sigma variation

Unit

Orbit Period

Value

303.7408

1-sigma variation

Unit

U parameter

Value

0.9

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	7.71830E-17	-7.07009E-16	1.68335E-16	3.95068E-13	-1.31884E-13	-4.28113E-13
e	-7.07009E-16	7.14861E-15	7.44272E-15	-3.29180E-12	1.41530E-12	3.21120E-12
i	1.68335E-16	7.44272E-15	4.97689E-12	1.78926E-10	-1.48008E-10	-4.27295E-11
Ω	3.95068E-13	-3.29180E-12	1.78926E-10	1.07871E-8	-8.32339E-9	-3.72863E-9
ω	-1.31884E-13	1.41530E-12	-1.48008E-10	-8.32339E-9	7.32891E-9	1.51038E-9
M	-4.28113E-13	3.21120E-12	-4.27295E-11	-3.72863E-9	1.51038E-9	3.38420E-9

Date of computation: 2026-03-12 13:01 UTC

Note: The ASCII file is in a format suitable for Orbfit input.

Download ASCII file:

Physical properties

Rotation Period
Quality
Amplitude
Rotation Direction
Spinvector L
Spinvector B

Rotational properties

Value

Unit

Source

Rotation Period

Value

Unit

Source

[-]

Quality

Value

Unit

Source

[-]

Amplitude

Value

Unit

mag

Source

[-]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

Unit

Source

[-]

Spinvector B

Value

Unit

Source

[-]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Unit

Source

[-]

Taxonomy (all)

Value

Unit

Source

[-]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

26.364

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[2]

Diameter

Value

14 - 30*

Unit

Source

[2]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

Unit

mag

Source

[-]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Unit

Source

[-]

Download this part as:

Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	Estimation	Estimated from absolute magnitude

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

1883

Unit

Source

[1]

Unobserved

Value

0.8

Unit

Source

[1]

Normalized RMS of residuals

Value

0.676711

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-01-14.642476

Unit

Source

[2]

Last Observation

Value

2026-03-12.293963

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

48 (3)

Unit

Source

[1]

Radar Summary

First Observation
Last Observation
Delay (Discarded)
Doppler (Discarded)
Total Optical Observations (Discarded)

Radar

Value

Unit

Source

First Observation

Value

Unit

Source

[-]

Last Observation

Value

Unit

Source

[-]

Delay (Discarded)

Value

0 (0)

Unit

Source

[-]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[-]

Total Radar Observations (Discarded)

Value

0 (0)

Unit

Source

[-]

Note: The ASCII file is in a format suitable for Orbfit input.

Sources

No.	Name	Additional
[1]	ESA Aegis	ESA orbit determination and impact monitoring system
[2]	MPC	Minor Planet Center: https://www.minorplanetcenter.net

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

* - these fields are required

Note: Ephemerides requests are limited to a maximum of 1000 points and a final date not exceeding 2040/12/31 00:00.

Close Approaches for 2021BW1 from 1950 to 2126

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1956-03-14 01:35	> 1 d	0.0169793	0.0103262	0.0089895
EARTH	1968-12-25 07:46	15.5	0.0061136	0.0058165	0.0000994
EARTH	1974-03-17 19:53	1.4	0.0133800	0.0133773	0.0000009
EARTH	1988-01-25 05:56	25.9	0.0569519	0.0569283	0.0000079
VENUS	1993-05-28 24:00	2.2	0.0185276	0.0185252	0.0000008
VENUS	1995-11-30 02:41	5.3	0.0324174	0.0324121	0.0000018
VENUS	1998-06-12 07:20	1.6	0.0326816	0.0326804	0.0000004
EARTH	2002-02-07 22:18	4.7	0.0602246	0.0602234	0.0000004
EARTH	2007-03-18 10:17	< 1 min	0.1964274	0.1964150	0.0000041
EARTH	2015-12-25 00:30	< 1 min	0.0143077	0.0143072	0.0000002
EARTH	2021-01-20 23:17	< 1 min	0.0576207	0.0576204	0.0000001
EARTH	2021-05-01 08:55	< 1 min	0.1769649	0.1769646	0.0000001
VENUS	2024-11-16 16:44	< 1 min	0.0327375	0.0327374	0.0000000
EARTH	2026-03-10 06:56	< 1 min	0.0372741	0.0372739	0.0000001
EARTH	2031-03-20 16:35	< 1 min	0.0217204	0.0217195	0.0000003
EARTH	2036-03-19 18:33	< 1 min	0.1736370	0.1736357	0.0000005
VENUS	2041-05-18 02:56	< 1 min	0.0447045	0.0447025	0.0000007
VENUS	2043-12-24 07:56	< 1 min	0.0381703	0.0381699	0.0000001
EARTH	2049-12-23 05:14	< 1 min	0.0629839	0.0629803	0.0000012
EARTH	2055-01-09 14:12	< 1 min	0.0447284	0.0447264	0.0000007
EARTH	2055-05-15 12:55	2.0	0.1971339	0.1971313	0.0000009
EARTH	2060-03-11 17:04	< 1 min	0.0328871	0.0328860	0.0000003
VENUS	2063-01-19 19:08	< 1 min	0.0460026	0.0460005	0.0000007
EARTH	2065-03-22 00:04	< 1 min	0.0796932	0.0796913	0.0000006
EARTH	2070-03-20 04:36	< 1 min	0.1885958	0.1885925	0.0000011
VENUS	2079-08-16 08:01	1.7	0.0326685	0.0326680	0.0000002
EARTH	2088-12-23 02:21	< 1 min	0.1340605	0.1340444	0.0000054
EARTH	2093-12-22 16:13	< 1 min	0.0500079	0.0499903	0.0000059
EARTH	2098-12-22 22:26	< 1 min	0.0326420	0.0326335	0.0000028
EARTH	2103-12-24 14:16	< 1 min	0.1323452	0.1323321	0.0000044
VENUS	2117-01-31 08:13	1.3	0.0244701	0.0244681	0.0000007
EARTH	2125-03-24 20:24	< 1 min	0.1154039	0.1153716	0.0000108

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
127.01736324	348.70442564	0.00153590	MINIMUM
227.84687114	72.73233691	0.01550072	MINIMUM
178.12052598	31.30693021	0.06459993	SADDLE
356.59552198	209.88584900	0.29570806	SADDLE
356.59731778	29.86854252	1.70466239	SADDLE
177.50240997	210.78909881	2.06411177	MAXIMUM

Download:

MOID Plots

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