Asteroids

2021KH help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.876

Aphelion (Q)

1.542

Eccentricity (e)

0.276

Inclination (i)

8.5

deg

Orbit period (P)

485.4

Earth MOID

0.00761

U parameter

6.5

Next Earth close approach

Date

2029-04-22

Nominal distance (from Earth center)

0.12007

17962624

Maximum Brightness

25.8

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

26.3

mag

Diameter

15 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-05-17

Observatory

ATLAS-MLO, Mauna Loa

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

1.208751

1-sigma variation

0.000066

Unit

Eccentricity (e)

Value

0.275617

1-sigma variation

0.000142

Unit

Inclination (i)

Value

8.4612

1-sigma variation

0.0085

Unit

Long. of Ascending Node (Ω)

Value

236.6855

1-sigma variation

0.0024

Unit

Arg. of Perihelion (ω)

Value

288.5420

1-sigma variation

0.0195

Unit

Mean Anomaly (M)

Value

184.61358

1-sigma variation

0.38108

Unit

Perihelion distance

Value

0.875599

1-sigma variation

Unit

Aphelion distance

Value

1.541904

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.013980

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.235724

1-sigma variation

Unit

MOID

Value

0.007607

1-sigma variation

Unit

Orbit Period

Value

485.4046

1-sigma variation

Unit

U parameter

Value

6.5

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.35781E-9	9.37618E-9	5.62692E-7	-1.55309E-7	-1.28969E-6	-2.51564E-5
e	9.37618E-9	2.01741E-8	1.21069E-6	-3.34160E-7	-2.77495E-6	-5.41261E-5
i	5.62692E-7	1.21069E-6	7.26566E-5	-2.00540E-5	-1.66530E-4	-3.24827E-3
Ω	-1.55309E-7	-3.34160E-7	-2.00540E-5	5.53513E-6	4.59635E-5	8.96558E-4
ω	-1.28969E-6	-2.77495E-6	-1.66530E-4	4.59635E-5	3.81697E-4	7.44501E-3
M	-2.51564E-5	-5.41261E-5	-3.24827E-3	8.96558E-4	7.44501E-3	1.45221E-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

26.309

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

15 - 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

Unit

Source

[1]

Unobserved

Value

1621

Unit

Source

[1]

Normalized RMS of residuals

Value

0.517739

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-05-17.373273

Unit

Source

[2]

Last Observation

Value

2021-06-03.529861

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

45 (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 2021KH 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	1972-05-20 20:36	> 1 d	0.0878044	0.0133910	0.0252909
EARTH	1976-05-09 16:11	> 1 w	0.0477637	0.0075146	0.0684732
EARTH	1980-03-19 19:12	> 1 mo	0.1683221	0.1228770	0.0212597
EARTH	1983-12-27 15:05	> 1 d	0.1172280	0.0949290	0.0373054
EARTH	1987-12-21 15:08	> 1 d	0.1422157	0.0945714	0.0464975
EARTH	2017-05-26 13:22	582.5	0.1765250	0.1506107	0.0086382
EARTH	2021-05-15 11:00	< 1 min	0.0101935	0.0101705	0.0000077
EARTH	2025-05-10 06:20	> 1 d	0.0453989	0.0211517	0.0081967
EARTH	2029-04-22 15:39	> 1 d	0.1200727	0.0946845	0.0085141
EARTH	2033-03-18 04:54	> 1 d	0.1693547	0.1605646	0.0030629
EARTH	2036-12-25 04:24	> 1 d	0.1667857	0.1383150	0.0101511
EARTH	2037-02-01 11:51	> 1 d	0.1676960	0.1513576	0.0055643
EARTH	2040-12-27 02:35	383.3	0.1068320	0.0988553	0.0049571
EARTH	2044-12-23 15:34	679.8	0.1149920	0.0996000	0.0077487
EARTH	2048-12-19 04:45	747.1	0.1972491	0.1547910	0.0148430
EARTH	2090-05-28 03:54	1287.3	0.1936411	0.1336930	0.0199828
EARTH	2094-05-21 18:45	> 1 d	0.0843951	0.0302860	0.0180837
EARTH	2098-05-15 09:17	1351.4	0.0071276	0.0070614	0.0014012
EARTH	2102-05-01 23:42	> 1 mo	0.0973377	0.0085102	0.3450478
EARTH	2106-03-22 00:38	> 1 mo	0.1680155	0.1220322	0.2221994
EARTH	2109-12-28 00:32	> 1 mo	0.1523073	0.1012962	0.7336424
EARTH	2113-12-27 09:29	> 1 mo	0.1024825	0.1023622	0.0610155
EARTH	2117-12-22 16:14	> 1 mo	0.1675476	0.1012740	1.3739743

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
54.38346411	131.05606535	0.00859455	MINIMUM
303.92051951	352.41553293	0.09945916	MINIMUM
355.07839062	55.83951441	0.17601069	SADDLE
179.44614493	243.44741538	0.56444742	SADDLE
2.62939031	245.84605714	1.87831046	SADDLE
182.48563505	65.75939556	2.53102702	MAXIMUM

Download:

MOID Plots

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