Asteroids

2021AF8 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.973

Aphelion (Q)

3.058

Eccentricity (e)

0.517

Inclination (i)

9.7

deg

Orbit period (P)

1045.1

Earth MOID

0.02825

U parameter

0.4

Next Earth close approach

Date

2041-06-04

Nominal distance (from Earth center)

0.15693

23475847

Maximum Brightness

18.9

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

20.1

mag

Diameter

250 - 600*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-01-14

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

2.015486

1-sigma variation

3.787E-8

Unit

Eccentricity (e)

Value

0.517024

1-sigma variation

1.006E-8

Unit

Inclination (i)

Value

9.7104

1-sigma variation

2.575E-6

Unit

Long. of Ascending Node (Ω)

Value

42.4548

1-sigma variation

8.053E-6

Unit

Arg. of Perihelion (ω)

Value

168.9625

1-sigma variation

8.938E-6

Unit

Mean Anomaly (M)

Value

215.35629

1-sigma variation

0.00002

Unit

Perihelion distance

Value

0.973432

1-sigma variation

Unit

Aphelion distance

Value

3.057540

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

2.006636

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.029989

1-sigma variation

Unit

MOID

Value

0.028246

1-sigma variation

Unit

Orbit Period

Value

1045.1247

1-sigma variation

Unit

U parameter

Value

0.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.43384E-15	3.61236E-16	4.39779E-15	-1.55936E-14	1.43908E-14	-6.22537E-13
e	3.61236E-16	1.01157E-16	-1.11155E-15	6.82444E-15	-1.79445E-14	-1.53691E-13
i	4.39779E-15	-1.11155E-15	6.62973E-12	-8.07093E-12	8.48868E-12	-2.30319E-12
Ω	-1.55936E-14	6.82444E-15	-8.07093E-12	6.48505E-11	-6.44563E-11	7.88370E-12
ω	1.43908E-14	-1.79445E-14	8.48868E-12	-6.44563E-11	7.98942E-11	-1.13541E-11
M	-6.22537E-13	-1.53691E-13	-2.30319E-12	7.88370E-12	-1.13541E-11	2.71395E-10

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

20.127

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

250 - 600*

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

3533

Unit

Source

[1]

Unobserved

Value

416

Unit

Source

[1]

Normalized RMS of residuals

Value

0.54936

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2014-12-01.335249

Unit

Source

[2]

Last Observation

Value

2024-08-03.545428

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

397 (3)

Unit

Source

[1]

Radar Summary

First Observation
Last Observation
Delay (Discarded)
Doppler (Discarded)
Total Optical Observations (Discarded)

Radar

Value

Unit

Source

First Observation

Value

2021-05-03

Unit

Source

[3]

Last Observation

Value

2021-05-05

Unit

Source

[3]

Delay (Discarded)

Value

1 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

3 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

4 (0)

Unit

Source

[1]

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
[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 2021AF8 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	1955-06-05 11:25	< 1 min	0.1674586	0.1674444	0.0000047
EARTH	1978-03-18 17:06	< 1 min	0.1668917	0.1668770	0.0000049
EARTH	2021-05-04 12:12	< 1 s	0.0224624	0.0224624	0.0000000
EARTH	2041-06-04 20:00	< 1 min	0.1569263	0.1569172	0.0000031
EARTH	2107-05-15 14:48	< 1 min	0.0380273	0.0380236	0.0000012

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
8.27884015	122.95986226	0.02691542	MINIMUM
1.25435561	290.64854694	1.96732239	SADDLE
180.22594912	289.76247830	2.06389435	SADDLE
180.59407246	109.97023903	4.06249837	MAXIMUM

Download:

MOID Plots

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