Asteroids

2021AD help

Last update: 2024-04-19 00:31 UTC

Orbital Properties

Epoch

60400.0

MJD

Orbit type

Apollo

Perihelion (q)

0.927

Aphelion (Q)

2.252

Eccentricity (e)

0.417

Inclination (i)

8.6

deg

Orbit period (P)

732.0

Earth MOID

0.01908

U parameter

8.6

Next Earth close approach

Date

2025-01-25

Nominal distance (from Earth center)

0.0577

8631290

Maximum Brightness

24.4

mag

Risk

Object is not in risk list

Object is not in priority list

Physical Properties

Absolute Magnitude (H)

24.5

mag

Diameter

30 - 80*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-01-02

Observatory

Mt. Lemmon Survey

Orbit Visualiser

Click the button to start Orbit Visualiser

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

60400.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.589600

1-sigma variation

0.004045

Unit

Eccentricity (e)

Value

0.416612

1-sigma variation

0.001779

Unit

Inclination (i)

Value

8.5736

1-sigma variation

0.0230

Unit

Long. of Ascending Node (Ω)

Value

296.4853

1-sigma variation

0.0040

Unit

Arg. of Perihelion (ω)

Value

206.2042

1-sigma variation

0.1235

Unit

Mean Anomaly (M)

Value

204.88621

1-sigma variation

2.60872

Unit

Perihelion distance

Value

0.927354

1-sigma variation

Unit

Aphelion distance

Value

2.251845

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

1.082036

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.026986

1-sigma variation

Unit

MOID

Value

0.019080

1-sigma variation

Unit

Orbit Period

Value

732.0321

1-sigma variation

Unit

U parameter

Value

8.6

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.63594E-5	7.19465E-6	9.28756E-5	-1.62702E-5	4.99669E-4	-1.05514E-2
e	7.19465E-6	3.16412E-6	4.08457E-5	-7.15502E-6	2.19750E-4	-4.64038E-3
i	9.28756E-5	4.08457E-5	5.27283E-4	-9.23542E-5	2.83680E-3	-5.99027E-2
Ω	-1.62702E-5	-7.15502E-6	-9.23542E-5	1.62160E-5	-4.96802E-4	1.04938E-2
ω	4.99669E-4	2.19750E-4	2.83680E-3	-4.96802E-4	1.52622E-2	-3.22275E-1
M	-1.05514E-2	-4.64038E-3	-5.99027E-2	1.04938E-2	-3.22275E-1	6.80543E0

Date of computation: 2024-02-21 14:29 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

24.466

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

30 - 80*

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 ODIM	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

1194

Unit

Source

[1]

Normalized RMS of residuals

Value

0.756071

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-01-02.126937

Unit

Source

[2]

Last Observation

Value

2021-01-11.08698

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

28 (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

[3]

Last Observation

Value

Unit

Source

[3]

Delay (Discarded)

Value

0 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

0 (0)

Unit

Source

[1]

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

Sources

No.	Name	Additional
[1]	ESA ODIM	ESA orbit determination and impact monitoring system
[2]	MPC	Minor Planet Center: https://www.minorplanetcenter.net
[3]	JPL Radar Observations	Jet Propulsion Laboratory: https://ssd.jpl.nasa.gov/dat/radar_data_ast.txt

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 2021AD from 1950 to 2124

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possibile distance in au	Distance uncert. in au
EARTH	2005-04-03 17:51	> 1 w	0.1838189	0.1394750	0.1402365
EARTH	2007-03-25 18:49	> 1 w	0.1487120	0.1312381	0.0871362
EARTH	2009-03-12 05:17	> 1 mo	0.1279300	0.1189246	0.0533221
EARTH	2011-02-26 22:27	> 1 mo	0.1129851	0.0992482	0.0544211
EARTH	2013-02-12 04:03	> 1 mo	0.0938896	0.0684078	0.0685754
EARTH	2015-02-01 07:17	> 1 mo	0.0726686	0.0422568	0.0777261
EARTH	2017-01-23 08:07	> 1 w	0.0515096	0.0275001	0.0709869
EARTH	2019-01-18 11:14	> 1 w	0.0350533	0.0218633	0.0394742
EARTH	2021-01-16 15:59	< 1 min	0.0320224	0.0315796	0.0001476
EARTH	2023-01-20 06:35	> 1 w	0.0407435	0.0231063	0.0409079
EARTH	2025-01-25 15:54	> 1 w	0.0576966	0.0305055	0.0688583
EARTH	2027-02-04 21:56	> 1 mo	0.0799902	0.0494994	0.0738903
EARTH	2029-02-16 19:37	> 1 mo	0.1003647	0.0784728	0.0651121
EARTH	2031-03-03 01:24	> 1 mo	0.1168304	0.1047874	0.0567887
EARTH	2033-03-17 00:23	> 1 mo	0.1336183	0.1225186	0.0683744
EARTH	2035-03-29 07:16	> 1 w	0.1604455	0.1329117	0.1220358

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