Asteroids

2021WH2 help

Last update: 2025-09-10 00:30 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Aten

Perihelion (q)

0.783

Aphelion (Q)

1.110

Eccentricity (e)

0.172

Inclination (i)

10.9

deg

Orbit period (P)

336.4

Earth MOID

0.01665

U parameter

5.4

Next Earth close approach

Date

2032-06-19

Nominal distance (from Earth center)

0.14032

20991431

Maximum Brightness

30.7

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

27.9

mag

Diameter

7 - 15*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-11-28

Observatory

Mt. Lemmon Survey

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

0.946575

1-sigma variation

0.000009

Unit

Eccentricity (e)

Value

0.172295

1-sigma variation

0.000144

Unit

Inclination (i)

Value

10.8610

1-sigma variation

0.0112

Unit

Long. of Ascending Node (Ω)

Value

65.4644

1-sigma variation

0.0002

Unit

Arg. of Perihelion (ω)

Value

121.1388

1-sigma variation

0.0071

Unit

Mean Anomaly (M)

Value

13.95227

1-sigma variation

0.01651

Unit

Perihelion distance

Value

0.783485

1-sigma variation

Unit

Aphelion distance

Value

1.109665

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.021634

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.171471

1-sigma variation

Unit

MOID

Value

0.016649

1-sigma variation

Unit

Orbit Period

Value

336.3807

1-sigma variation

Unit

U parameter

Value

5.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	8.91476E-11	7.70755E-10	2.98701E-8	4.44473E-10	-6.42664E-8	-4.87416E-8
e	7.70755E-10	2.08332E-8	1.52555E-6	2.10595E-8	-7.93729E-7	1.44231E-6
i	2.98701E-8	1.52555E-6	1.25572E-4	1.77132E-6	-4.19199E-5	1.49100E-4
Ω	4.44473E-10	2.10595E-8	1.77132E-6	2.62647E-8	-5.76300E-7	1.97506E-6
ω	-6.42664E-8	-7.93729E-7	-4.19199E-5	-5.76300E-7	5.07052E-5	3.30298E-6
M	-4.87416E-8	1.44231E-6	1.49100E-4	1.97506E-6	3.30298E-6	2.72505E-4

Date of computation: 2025-09-10 00:30 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

27.948

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[2]

Diameter

Value

7 - 15*

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

0.9

Unit

Source

[1]

Unobserved

Value

1392

Unit

Source

[1]

Normalized RMS of residuals

Value

0.672309

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-11-28.288439

Unit

Source

[2]

Last Observation

Value

2021-11-29.221306

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

24 (0)

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

Close Approaches for 2021WH2 from 1950 to 2125

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1954-06-16 17:17	1414.9	0.1477026	0.1458291	0.0007292
EARTH	1965-05-18 06:49	753.3	0.1946082	0.1931402	0.0004971
EARTH	1965-11-19 18:15	208.1	0.1143294	0.1121044	0.0007430
EARTH	1976-11-29 23:03	98.5	0.0243767	0.0205484	0.0013617
EARTH	1987-11-30 19:54	76.0	0.0213377	0.0184008	0.0010708
EARTH	1998-05-19 17:32	946.2	0.1888249	0.1868906	0.0006582
EARTH	1998-11-15 06:57	417.9	0.1335795	0.1302382	0.0011170
EARTH	2009-06-18 21:52	461.6	0.1405049	0.1397785	0.0002549
EARTH	2010-11-28 14:29	30.1	0.1932940	0.1908825	0.0008039
EARTH	2020-07-16 23:27	102.0	0.1803797	0.1795617	0.0002749
EARTH	2021-11-30 19:31	< 1 min	0.0159468	0.0159006	0.0000154
EARTH	2032-06-19 19:33	365.0	0.1403191	0.1397610	0.0001931
EARTH	2033-11-29 23:04	46.3	0.1601527	0.1557676	0.0014622
EARTH	2044-11-23 13:50	691.1	0.0908258	0.0813641	0.0031759
EARTH	2055-06-20 18:01	1075.5	0.1410645	0.1400792	0.0003995
EARTH	2056-11-28 19:47	95.3	0.1823059	0.1737938	0.0028385
EARTH	2066-07-18 22:55	211.3	0.1856254	0.1828778	0.0009287
EARTH	2067-12-01 05:48	52.8	0.0173330	0.0170625	0.0002283
EARTH	2078-05-29 04:15	> 1 d	0.1726992	0.1593309	0.0066926
EARTH	2078-10-31 16:31	> 1 d	0.1710205	0.1374279	0.0121208
EARTH	2089-07-06 04:07	> 1 d	0.1432209	0.1391901	0.0075696
EARTH	2090-12-01 07:39	581.4	0.0866541	0.0194673	0.0344465
EARTH	2101-11-23 16:53	> 1 d	0.0963787	0.0405076	0.0210330
EARTH	2112-06-28 09:16	282.1	0.1374893	0.1366022	0.0002964
EARTH	2113-12-01 15:26	84.4	0.1244866	0.1152483	0.0030839
EARTH	2124-05-29 18:58	> 1 w	0.1729621	0.1582243	0.0088311
EARTH	2124-10-28 08:33	> 1 w	0.1796134	0.1406258	0.0148408

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
251.26819775	326.91767369	0.01636928	MINIMUM
79.77706570	173.45540562	0.13577421	MINIMUM
158.57085504	247.30079413	0.21452477	SADDLE
349.17699576	70.64831341	0.26194737	SADDLE
3.73782033	268.06911377	1.77884491	SADDLE
187.58451678	92.07111066	2.10241008	MAXIMUM

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MOID Plots

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