Asteroids

2021RD help

Last update: 2026-07-30 14:25 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Amor

Perihelion (q)

1.069

Aphelion (Q)

1.625

Eccentricity (e)

0.206

Inclination (i)

15.0

deg

Orbit period (P)

571.0

Earth MOID

0.08026

U parameter

6.6

Next Earth close approach

Date

2046-08-17

Nominal distance (from Earth center)

0.09382

14034735

Maximum Brightness

18.8

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

22.4

mag

Diameter

90 - 200*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-09-03

Observatory

University of Arizona 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

61200.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.346945

1-sigma variation

0.000126

Unit

Eccentricity (e)

Value

0.206406

1-sigma variation

0.000065

Unit

Inclination (i)

Value

14.9882

1-sigma variation

0.0031

Unit

Long. of Ascending Node (Ω)

Value

330.6329

1-sigma variation

0.0015

Unit

Arg. of Perihelion (ω)

Value

327.9404

1-sigma variation

0.0011

Unit

Mean Anomaly (M)

Value

49.29343

1-sigma variation

0.16022

Unit

Perihelion distance

Value

1.068929

1-sigma variation

Unit

Aphelion distance

Value

1.624962

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.086002

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.574477

1-sigma variation

Unit

MOID

Value

0.080258

1-sigma variation

Unit

Orbit Period

Value

570.9834

1-sigma variation

Unit

U parameter

Value

6.6

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.59923E-8	8.18386E-9	3.91117E-7	1.88725E-7	1.25199E-7	-2.02618E-5
e	8.18386E-9	4.19028E-9	1.99933E-7	9.65661E-8	6.43387E-8	-1.03692E-5
i	3.91117E-7	1.99933E-7	9.59840E-6	4.62219E-6	2.99095E-6	-4.95460E-4
Ω	1.88725E-7	9.65661E-8	4.62219E-6	2.23077E-6	1.46079E-6	-2.39098E-4
ω	1.25199E-7	6.43387E-8	2.99095E-6	1.46079E-6	1.20977E-6	-1.58829E-4
M	-2.02618E-5	-1.03692E-5	-4.95460E-4	-2.39098E-4	-1.58829E-4	2.56715E-2

Date of computation: 2026-07-30 14:25 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

22.369

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[2]

Diameter

Value

90 - 200*

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

1773

Unit

Source

[1]

Normalized RMS of residuals

Value

0.509054

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-08-29.593177

Unit

Source

[2]

Last Observation

Value

2021-09-28.167106

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

23 (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

Filters

Initial Date: *

Final Date: *

Normalised Only accepted

Max residual (arcsec):

* - these fields are required

Plot

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

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Note: Ephemerides requests are limited to a maximum of 1000 points and a final date not exceeding 2040/12/31 00:00.

Close Approaches for 2021RD from 1950 to 2126

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1960-08-18 12:51	1175.9	0.0891993	0.0809967	0.0128235
EARTH	1985-08-20 06:22	1038.6	0.1224674	0.0803254	0.0201195
EARTH	2021-08-15 16:34	< 1 min	0.1597559	0.1596533	0.0000342
EARTH	2046-08-17 10:10	664.7	0.0938164	0.0802136	0.0106130
EARTH	2071-08-18 16:54	> 1 d	0.0805843	0.0804840	0.0026078
EARTH	2096-08-18 16:57	> 1 d	0.0838254	0.0797736	0.0543773
EARTH	2121-08-21 21:55	> 1 w	0.1250350	0.0772288	0.3878911

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
21.55207300	221.35555224	0.08025782	MINIMUM
165.70484239	3.50714463	0.67200716	SADDLE
355.02653688	9.13857848	2.04708007	SADDLE
182.27972578	196.69763185	2.63554438	MAXIMUM

Download:

MOID Plots

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