Asteroids

2021OK1 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.909

Aphelion (Q)

3.446

Eccentricity (e)

0.583

Inclination (i)

8.8

deg

Orbit period (P)

1173.6

Earth MOID

0.00521

U parameter

7.4

Next Earth close approach

Date

2050-04-26

Nominal distance (from Earth center)

0.15844

23702324

Maximum Brightness

26.1

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

27.1

mag

Diameter

10 - 23*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-07-30

Observatory

Pan-STARRS 1, Haleakala

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

2.177470

1-sigma variation

0.001396

Unit

Eccentricity (e)

Value

0.582544

1-sigma variation

0.000291

Unit

Inclination (i)

Value

8.8053

1-sigma variation

0.0031

Unit

Long. of Ascending Node (Ω)

Value

306.1307

1-sigma variation

0.0002

Unit

Arg. of Perihelion (ω)

Value

313.2584

1-sigma variation

0.0004

Unit

Mean Anomaly (M)

Value

134.56054

1-sigma variation

0.48248

Unit

Perihelion distance

Value

0.908997

1-sigma variation

Unit

Aphelion distance

Value

3.445942

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.011671

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

1.408873

1-sigma variation

Unit

MOID

Value

0.005215

1-sigma variation

Unit

Orbit Period

Value

1173.6177

1-sigma variation

Unit

U parameter

Value

7.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.94939E-6	4.06186E-7	4.27360E-6	3.05651E-7	-5.17868E-7	-6.73638E-4
e	4.06186E-7	8.46352E-8	8.90467E-7	6.36900E-8	-1.07918E-7	-1.40363E-4
i	4.27360E-6	8.90467E-7	9.36923E-6	6.69899E-7	-1.13476E-6	-1.47680E-3
Ω	3.05651E-7	6.36900E-8	6.69899E-7	4.81467E-8	-8.18898E-8	-1.05622E-4
ω	-5.17868E-7	-1.07918E-7	-1.13476E-6	-8.18898E-8	1.41004E-7	1.78956E-4
M	-6.73638E-4	-1.40363E-4	-1.47680E-3	-1.05622E-4	1.78956E-4	2.32784E-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

27.065

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

10 - 23*

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

1535

Unit

Source

[1]

Normalized RMS of residuals

Value

0.572941

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-07-30.492404

Unit

Source

[2]

Last Observation

Value

2021-08-13.455424

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

26 (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 2021OK1 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	1960-04-11 22:28	> 1 w	0.1988469	0.1506244	0.1883260
EARTH	1976-07-03 12:40	> 1 mo	0.1179387	0.0275481	0.1804830
EARTH	2005-04-24 02:35	> 1 w	0.1523777	0.1513054	0.0111999
EARTH	2021-07-27 09:26	< 1 min	0.0056857	0.0056788	0.0000023
EARTH	2050-04-26 03:39	> 1 w	0.1584403	0.1560341	0.0255216
EARTH	2066-07-17 20:30	> 1 mo	0.0598744	0.0014017	0.2188365
EARTH	2111-04-28 12:05	> 1 mo	0.1613134	0.1578543	0.1454169

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
23.97491659	202.45143748	0.00567218	MINIMUM
339.19190304	116.96856457	0.15395380	MINIMUM
351.59090660	140.45616945	0.16036832	SADDLE
0.05813073	337.19599490	1.89011579	SADDLE
179.76620446	337.46160786	2.46962353	SADDLE
180.35935975	157.76807887	4.45604931	MAXIMUM

Download:

MOID Plots

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

Level lines of the squared distance function

2021OK1

Date in UTC	MJD	σ	σ_imp	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS	TS
2111-07-28.870	92294.870	1.383	0.000	0.90 ± 0.003	2.68E5	1.13E-6	8.24E-2	-7.23	0


Based on 26 optical observations (of which 0 are rejected as outliers) from 2021/07/30.492 to 2021/08/13.455.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.33 and 1.33 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: