Asteroids

2021WA1 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Aten

Perihelion (q)

0.560

Aphelion (Q)

1.426

Eccentricity (e)

0.436

Inclination (i)

3.3

deg

Orbit period (P)

361.4

Earth MOID

0.00090

U parameter

6.4

Next Earth close approach

Date

2046-04-04

Nominal distance (from Earth center)

0.16577

24798153

Maximum Brightness

26.1

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

27.6

mag

Diameter

8 - 18*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-11-27

Observatory

Catalina Sky 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

0.992954

1-sigma variation

0.000044

Unit

Eccentricity (e)

Value

0.436037

1-sigma variation

0.000097

Unit

Inclination (i)

Value

3.2582

1-sigma variation

0.0009

Unit

Long. of Ascending Node (Ω)

Value

65.2163

1-sigma variation

0.0001

Unit

Arg. of Perihelion (ω)

Value

243.8862

1-sigma variation

0.0011

Unit

Mean Anomaly (M)

Value

73.43408

1-sigma variation

0.11176

Unit

Perihelion distance

Value

0.559989

1-sigma variation

Unit

Aphelion distance

Value

1.425918

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.007938

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.339840

1-sigma variation

Unit

MOID

Value

0.000903

1-sigma variation

Unit

Orbit Period

Value

361.4031

1-sigma variation

Unit

U parameter

Value

6.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.90633E-9	4.25398E-9	3.88659E-8	-2.40670E-9	-4.88729E-8	-4.87971E-6
e	4.25398E-9	9.49369E-9	8.67403E-8	-5.37051E-9	-1.09124E-7	-1.08891E-5
i	3.88659E-8	8.67403E-8	7.92730E-7	-4.90552E-8	-9.97217E-7	-9.94871E-5
Ω	-2.40670E-9	-5.37051E-9	-4.90552E-8	3.05389E-9	6.16823E-8	6.16052E-6
ω	-4.88729E-8	-1.09124E-7	-9.97217E-7	6.16823E-8	1.25747E-6	1.25105E-4
M	-4.87971E-6	-1.08891E-5	-9.94871E-5	6.16052E-6	1.25105E-4	1.24908E-2

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

27.609

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

8 - 18*

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

[-]

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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

Unit

Source

[1]

Unobserved

Value

1425

Unit

Source

[1]

Normalized RMS of residuals

Value

0.454253

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-11-27.24502

Unit

Source

[2]

Last Observation

Value

2021-12-04.30837

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

74 (1)

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 2021WA1 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
VENUS	1971-03-10 13:58	> 1 mo	0.0366080	0.0087731	1.8977096
VENUS	1979-06-07 08:03	> 1 d	0.0079315	0.0079278	0.0016926
EARTH	1986-03-30 11:51	> 1 d	0.1794922	0.0419317	0.0694210
EARTH	1987-04-01 23:04	> 1 d	0.1268865	0.0416627	0.0681257
EARTH	1988-04-03 05:59	> 1 d	0.0784810	0.0414978	0.0607722
EARTH	1989-04-05 07:32	> 1 d	0.0443113	0.0414536	0.0244232
EARTH	1990-04-07 02:45	> 1 d	0.0530279	0.0414352	0.0447574
EARTH	1991-04-08 14:27	> 1 d	0.0940048	0.0413899	0.0678783
EARTH	1992-04-08 02:03	1219.6	0.1434918	0.0410342	0.0744582
EARTH	1993-04-05 20:12	> 1 d	0.1945535	0.0394040	0.0751178
VENUS	2010-07-21 11:24	339.3	0.0090493	0.0087454	0.0008517
EARTH	2017-11-27 00:21	130.6	0.1795906	0.1756201	0.0013235
EARTH	2018-11-24 23:41	21.2	0.1308376	0.1275077	0.0011100
EARTH	2019-11-25 05:54	13.2	0.0849760	0.0826245	0.0007838
EARTH	2020-11-25 06:51	14.9	0.0408927	0.0396266	0.0004220
EARTH	2021-11-26 13:44	< 1 s	0.0020615	0.0020599	0.0000005
EARTH	2022-11-25 11:14	9.5	0.0604899	0.0591341	0.0004519
EARTH	2023-11-25 11:17	20.6	0.1220798	0.1194860	0.0008646
EARTH	2024-11-27 23:39	163.5	0.1834870	0.1799078	0.0011931
EARTH	2046-04-04 06:41	189.8	0.1657654	0.1574785	0.0027674
EARTH	2047-04-05 13:29	4.1	0.1096879	0.1030397	0.0022298
EARTH	2048-04-03 18:43	50.4	0.0611791	0.0573968	0.0013110
EARTH	2049-04-02 08:23	47.3	0.0474119	0.0463133	0.0004230
EARTH	2050-03-31 13:24	32.8	0.0861874	0.0837778	0.0008080
EARTH	2051-03-29 12:18	11.2	0.1415828	0.1401467	0.0004791
VENUS	2084-12-24 17:18	135.3	0.0227858	0.0188052	0.0013534
VENUS	2104-12-07 17:42	1296.3	0.0080477	0.0072952	0.0059028
EARTH	2113-12-04 11:17	> 1 w	0.1786075	0.0009414	0.2399422
EARTH	2114-12-02 14:30	> 1 w	0.1233926	0.0008728	0.2533682
EARTH	2115-11-30 22:07	> 1 w	0.0696317	0.0007431	0.2616493
EARTH	2116-11-28 12:21	> 1 w	0.0193384	0.0005481	0.2552732
EARTH	2117-11-27 16:01	> 1 d	0.0182310	0.0002236	0.0808381
EARTH	2118-11-26 20:13	> 1 d	0.0682342	0.0011109	0.1477098
EARTH	2119-11-26 23:58	> 1 d	0.1207745	0.0015083	0.3639443
EARTH	2120-11-28 12:10	> 1 mo	0.1737019	0.0037238	0.5514436
VENUS	2122-10-09 21:42	> 1 mo	0.0151264	0.0073328	1.0410792

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
89.22036012	322.59420367	0.00088522	MINIMUM
269.62325425	89.78985409	0.04506443	MINIMUM
179.74875013	26.38909737	0.44475180	SADDLE
358.82887410	205.70039579	0.45617003	SADDLE
358.64372733	25.37489579	1.54485448	SADDLE
179.33076467	206.12114732	2.43975299	MAXIMUM

Download:

MOID Plots

Click on the images to zoom-in and zoom-out

Level lines of the squared distance function

2021WA1

Date in UTC	MJD	σ	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS
2116-11-27.906	94243.906	1.294	0.70 ± 0.000	7.13E2	5.20E-4	5.60E-2	-4.72
2117-11-28.141	94609.141	1.141	0.27 ± 0.000	6.91E3	7.56E-5	5.60E-2	-5.56
2119-11-28.605	95339.605	1.291	0.30 ± 0.000	5.52E7	7.84E-9	5.60E-2	-9.56
2120-11-27.865	95704.865	1.290	0.46 ± 0.000	3.95E7	1.06E-8	5.61E-2	-9.43


Based on 74 optical observations (of which 1 are rejected as outliers) from 2021/11/27.245 to 2021/12/04.308.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.28 and 1.28 Earth radii.
Coordinates for LOV = EQU scaled= 1 second= F.
AstOD software version= 4.0, Date of computation=20250805 130500.123 UTC.

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Download Impactor Table as: