Asteroids

2021RQ9 help

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

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.754

Aphelion (Q)

2.061

Eccentricity (e)

0.464

Inclination (i)

8.0

deg

Orbit period (P)

610.1

Earth MOID

0.00255

U parameter

6.8

Next Earth close approach

Date

2031-10-03

Nominal distance (from Earth center)

0.14029

20986514

Maximum Brightness

25.9

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

26.2

mag

Diameter

15 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-09-11

Observatory

Pan-STARRS 2, 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

61200.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.407780

1-sigma variation

0.000197

Unit

Eccentricity (e)

Value

0.464098

1-sigma variation

0.000100

Unit

Inclination (i)

Value

8.0452

1-sigma variation

0.0015

Unit

Long. of Ascending Node (Ω)

Value

174.9882

1-sigma variation

0.0001

Unit

Arg. of Perihelion (ω)

Value

256.6952

1-sigma variation

0.0001

Unit

Mean Anomaly (M)

Value

267.36199

1-sigma variation

0.20447

Unit

Perihelion distance

Value

0.754432

1-sigma variation

Unit

Aphelion distance

Value

2.061128

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.242399

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.007586

1-sigma variation

Unit

MOID

Value

0.002545

1-sigma variation

Unit

Orbit Period

Value

610.0993

1-sigma variation

Unit

U parameter

Value

6.8

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	3.89980E-8	1.98313E-8	2.97903E-7	-1.99033E-8	2.22366E-8	-4.03794E-5
e	1.98313E-8	1.00847E-8	1.51491E-7	-1.01205E-8	1.13227E-8	-2.05338E-5
i	2.97903E-7	1.51491E-7	2.27576E-6	-1.52067E-7	1.70006E-7	-3.08455E-4
Ω	-1.99033E-8	-1.01205E-8	-1.52067E-7	1.01808E-8	-1.12210E-8	2.06083E-5
ω	2.22366E-8	1.13227E-8	1.70006E-7	-1.12210E-8	1.54018E-8	-2.30246E-5
M	-4.03794E-5	-2.05338E-5	-3.08455E-4	2.06083E-5	-2.30246E-5	4.18098E-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

26.199

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

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

1881

Unit

Source

[1]

Normalized RMS of residuals

Value

0.470489

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-09-07.25391

Unit

Source

[2]

Last Observation

Value

2021-09-16.959552

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

67 (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:*

* - these fields are required

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 2021RQ9 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	1950-09-06 22:01	> 1 mo	0.1604921	0.0080162	0.9945014
EARTH	1969-02-26 00:14	> 1 w	0.1374180	0.0592810	0.4451396
EARTH	1974-02-08 05:47	> 1 mo	0.1420322	0.0535511	0.2414383
EARTH	1983-10-20 06:42	> 1 w	0.1963125	0.1012648	0.0331551
EARTH	1988-09-14 09:18	> 1 d	0.0307612	0.0038525	0.0662304
EARTH	2007-02-22 03:39	> 1 d	0.0667797	0.0586420	0.0089703
EARTH	2021-09-17 06:49	< 1 s	0.0034243	0.0034221	0.0000007
EARTH	2026-09-23 10:44	932.4	0.0706858	0.0515745	0.0063748
EARTH	2031-10-03 23:23	> 1 d	0.1402862	0.1123440	0.0093317
EARTH	2067-01-31 19:28	> 1 w	0.1723017	0.0471940	0.0725043
EARTH	2072-02-12 22:40	> 1 w	0.1066053	0.0594853	0.0863907
EARTH	2077-02-17 21:54	> 1 w	0.0623683	0.0613308	0.0218789
EARTH	2082-02-23 01:30	> 1 w	0.0951583	0.0605717	0.1450203
EARTH	2087-02-28 15:27	> 1 w	0.1859972	0.0584478	0.2194944

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
308.07275704	250.52783202	0.00254505	MINIMUM
51.96337633	44.53846363	0.06263787	MINIMUM
0.65327345	328.89475951	0.25987545	SADDLE
179.98429137	146.88588425	1.06543221	SADDLE
358.93270853	146.09776238	1.76448536	SADDLE
179.35453145	326.50609809	3.04110386	MAXIMUM

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MOID Plots

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