Asteroids

2021LK help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Aten

Perihelion (q)

0.743

Aphelion (Q)

1.147

Eccentricity (e)

0.214

Inclination (i)

7.2

deg

Orbit period (P)

335.6

Earth MOID

0.00295

U parameter

4.8

Next Earth close approach

Date

2031-01-26

Nominal distance (from Earth center)

0.13522

20228616

Maximum Brightness

25.9

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

26.7

mag

Diameter

12 - 28*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-06-03

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

0.945024

1-sigma variation

0.000004

Unit

Eccentricity (e)

Value

0.214161

1-sigma variation

0.000044

Unit

Inclination (i)

Value

7.1958

1-sigma variation

0.0016

Unit

Long. of Ascending Node (Ω)

Value

76.6721

1-sigma variation

0.0001

Unit

Arg. of Perihelion (ω)

Value

300.2190

1-sigma variation

0.0006

Unit

Mean Anomaly (M)

Value

208.33711

1-sigma variation

0.01609

Unit

Perihelion distance

Value

0.742636

1-sigma variation

Unit

Aphelion distance

Value

1.147411

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.171186

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.005826

1-sigma variation

Unit

MOID

Value

0.002951

1-sigma variation

Unit

Orbit Period

Value

335.5540

1-sigma variation

Unit

U parameter

Value

4.8

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.38561E-11	-1.65059E-10	-5.97325E-9	3.29849E-10	2.07086E-9	-5.98658E-8
e	-1.65059E-10	1.97810E-9	7.16074E-8	-3.95904E-9	-2.51061E-8	7.15030E-7
i	-5.97325E-9	7.16074E-8	2.59231E-6	-1.43360E-7	-9.09353E-7	2.58795E-5
Ω	3.29849E-10	-3.95904E-9	-1.43360E-7	7.94999E-9	5.03727E-8	-1.42986E-6
ω	2.07086E-9	-2.51061E-8	-9.09353E-7	5.03727E-8	3.25646E-7	-9.01677E-6
M	-5.98658E-8	7.15030E-7	2.58795E-5	-1.42986E-6	-9.01677E-6	2.58953E-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

26.652

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

12 - 28*

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

1600

Unit

Source

[1]

Normalized RMS of residuals

Value

0.555534

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-05-20.557422

Unit

Source

[2]

Last Observation

Value

2021-06-07.161245

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

26 (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 2021LK 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	1956-12-30 18:32	1012.3	0.1410651	0.1373005	0.0012794
EARTH	1958-06-05 05:28	58.1	0.0876769	0.0820621	0.0018718
EARTH	1968-04-21 23:53	280.7	0.1753911	0.1749717	0.0001399
VENUS	1975-02-28 15:50	347.8	0.0495884	0.0453726	0.0014882
EARTH	1978-01-26 03:24	175.7	0.1142445	0.1106271	0.0012467
EARTH	1979-05-31 17:49	470.5	0.0931368	0.0882644	0.0016245
EARTH	1989-01-14 20:32	51.6	0.1042123	0.1039589	0.0000849
EARTH	1990-06-06 20:19	3.9	0.0223481	0.0216924	0.0002186
EARTH	1999-02-02 00:35	2.3	0.1923343	0.1921478	0.0000622
EARTH	2000-05-10 13:52	87.5	0.1457390	0.1453408	0.0001328
EARTH	2009-12-24 04:40	20.7	0.1593273	0.1592227	0.0000349
EARTH	2010-02-27 05:05	26.5	0.1732300	0.1731041	0.0000419
EARTH	2011-06-04 03:45	4.4	0.1387956	0.1384358	0.0001199
EARTH	2020-01-23 18:35	16.9	0.0947957	0.0947875	0.0000030
EARTH	2021-06-06 14:55	< 1 s	0.0078114	0.0078063	0.0000017
EARTH	2031-01-26 16:13	36.9	0.1352199	0.1341164	0.0003694
EARTH	2032-05-14 00:54	218.8	0.1406478	0.1399392	0.0002363
EARTH	2042-12-09 09:24	502.4	0.1834000	0.1822353	0.0003898
EARTH	2043-03-14 21:13	497.5	0.1889314	0.1884273	0.0001683
EARTH	2044-06-04 01:56	21.9	0.1159946	0.1143487	0.0005486
EARTH	2054-01-25 19:01	14.7	0.1308886	0.1305753	0.0001046
EARTH	2055-05-05 02:43	58.6	0.1627279	0.1624081	0.0001066
EARTH	2066-12-02 11:55	563.3	0.1975273	0.1965706	0.0003204
EARTH	2067-03-20 15:00	555.9	0.1972986	0.1972009	0.0000329
EARTH	2068-06-06 14:01	32.1	0.0739379	0.0712412	0.0008989
EARTH	2079-01-19 18:14	7.5	0.0903654	0.0902828	0.0000275
EARTH	2080-05-19 15:05	26.2	0.1342290	0.1340157	0.0000711
EARTH	2091-12-15 09:42	578.7	0.1709792	0.1694209	0.0005222
EARTH	2092-03-02 04:49	665.4	0.1861795	0.1851578	0.0003409
EARTH	2093-06-08 00:01	10.8	0.0184876	0.0161110	0.0007934
EARTH	2103-12-25 05:43	> 1 d	0.1553286	0.1399942	0.0055475
EARTH	2104-02-16 01:46	> 1 d	0.1730091	0.1569156	0.0054135
EARTH	2105-06-08 22:05	141.0	0.0212293	0.0026471	0.0101358
EARTH	2115-01-31 01:58	> 1 d	0.1600721	0.0959821	0.0634115
EARTH	2116-05-01 09:39	> 1 mo	0.1702076	0.0954125	0.0361339

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
250.20038696	153.22011190	0.00198558	MINIMUM
89.88224600	16.40735110	0.09084708	MINIMUM
167.66277292	84.05135082	0.19147052	SADDLE
349.27651386	262.73604622	0.27616166	SADDLE
353.38849057	87.87198244	1.74016586	SADDLE
177.06219216	271.66634430	2.14305874	MAXIMUM

Download:

MOID Plots

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