Asteroids

2021HM2 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.604

Aphelion (Q)

1.667

Eccentricity (e)

0.468

Inclination (i)

11.5

deg

Orbit period (P)

442.0

Earth MOID

0.00458

U parameter

7.4

Next Earth close approach

Date

2028-11-24

Nominal distance (from Earth center)

0.09839

14718838

Maximum Brightness

22.8

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

23.9

mag

Diameter

40 - 100*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-04-19

Observatory

MAPS, San Pedro de Atacama

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

1.135567

1-sigma variation

0.000273

Unit

Eccentricity (e)

Value

0.468402

1-sigma variation

0.000244

Unit

Inclination (i)

Value

11.4752

1-sigma variation

0.0065

Unit

Long. of Ascending Node (Ω)

Value

216.5684

1-sigma variation

0.0005

Unit

Arg. of Perihelion (ω)

Value

103.4906

1-sigma variation

0.0019

Unit

Mean Anomaly (M)

Value

229.87393

1-sigma variation

0.45766

Unit

Perihelion distance

Value

0.603664

1-sigma variation

Unit

Aphelion distance

Value

1.667469

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.012929

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.194054

1-sigma variation

Unit

MOID

Value

0.004582

1-sigma variation

Unit

Orbit Period

Value

441.9950

1-sigma variation

Unit

U parameter

Value

7.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	7.43853E-8	6.65868E-8	1.75977E-6	-1.24569E-7	-5.11666E-7	-1.24821E-4
e	6.65868E-8	5.96080E-8	1.57532E-6	-1.11507E-7	-4.57819E-7	-1.11734E-4
i	1.75977E-6	1.57532E-6	4.16334E-5	-2.94707E-6	-1.20999E-5	-2.95293E-3
Ω	-1.24569E-7	-1.11507E-7	-2.94707E-6	2.08659E-7	8.57109E-7	2.09031E-4
ω	-5.11666E-7	-4.57819E-7	-1.20999E-5	8.57109E-7	3.53975E-6	8.58595E-4
M	-1.24821E-4	-1.11734E-4	-2.95293E-3	2.09031E-4	8.58595E-4	2.09452E-1

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

23.944

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

40 - 100*

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

Unit

Source

[1]

Unobserved

Value

1604

Unit

Source

[1]

Normalized RMS of residuals

Value

0.609067

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-04-19.18129

Unit

Source

[2]

Last Observation

Value

2021-04-25.895787

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

61 (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 2021HM2 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	1963-04-27 23:32	> 1 mo	0.0463599	0.0059150	0.8087166
EARTH	1970-11-24 21:16	> 1 mo	0.1051544	0.0792220	0.4293212
EARTH	1986-04-25 08:40	> 1 d	0.0138249	0.0049493	0.0468195
EARTH	1992-05-03 09:21	> 1 d	0.1987507	0.0569323	0.0473976
EARTH	1993-11-15 10:53	> 1 d	0.1276081	0.0828314	0.0368494
EARTH	1999-11-27 15:27	> 1 d	0.1368341	0.0822135	0.0344684
EARTH	2021-04-26 08:38	< 1 s	0.0128543	0.0128335	0.0000069
EARTH	2028-11-24 00:23	1136.4	0.0983894	0.0811776	0.0091195
EARTH	2044-04-25 22:09	> 1 d	0.0058562	0.0033396	0.0462434
EARTH	2061-05-04 03:08	> 1 mo	0.1953659	0.0068695	1.9891295
EARTH	2062-11-19 13:22	> 1 mo	0.0832689	0.0792784	0.6773795
EARTH	2072-04-21 07:01	> 1 mo	0.1066207	0.0033445	3.6864153
EARTH	2079-11-30 00:37	> 1 mo	0.1886486	0.0827027	3.9225111
EARTH	2089-04-28 22:11	> 1 mo	0.0635018	0.0024929	4.5415821
EARTH	2090-11-10 08:16	> 1 mo	0.1740214	0.0884729	3.6503523
EARTH	2107-11-26 14:42	> 1 d	0.1130395	0.0425582	0.0412471
EARTH	2117-04-27 18:16	> 1 mo	0.0092191	0.0013411	2.2876209
EARTH	2118-11-09 00:21	> 1 mo	0.1900586	0.0752550	5.9186241

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
284.24165314	112.42996395	0.00404117	MINIMUM
70.48665996	317.23318431	0.08030475	MINIMUM
356.65632742	213.30225402	0.43732043	SADDLE
178.12627996	36.59715893	0.72488587	SADDLE
357.83063921	35.31165794	1.58344508	SADDLE
179.70853227	217.55031163	2.66829090	MAXIMUM

Download:

MOID Plots

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