Asteroids

2021GX9 help

Last update: 2025-07-29 02:36 UTC

Orbital Properties

Epoch

60800.0

MJD

Orbit type

Apollo

Perihelion (q)

0.746

Aphelion (Q)

3.185

Eccentricity (e)

0.620

Inclination (i)

4.1

deg

Orbit period (P)

1006.5

Earth MOID

0.00027

U parameter

7.1

Next Earth close approach

Date

2032-04-22

Nominal distance (from Earth center)

0.06832

10220251

Maximum Brightness

23.2

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

25.2

mag

Diameter

24 - 50*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-04-14

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

60800.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.965579

1-sigma variation

0.000713

Unit

Eccentricity (e)

Value

0.620246

1-sigma variation

0.000155

Unit

Inclination (i)

Value

4.1337

1-sigma variation

0.0010

Unit

Long. of Ascending Node (Ω)

Value

207.3881

1-sigma variation

0.0071

Unit

Arg. of Perihelion (ω)

Value

70.5310

1-sigma variation

0.0067

Unit

Mean Anomaly (M)

Value

153.26841

1-sigma variation

0.27533

Unit

Perihelion distance

Value

0.746437

1-sigma variation

Unit

Aphelion distance

Value

3.184722

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.001926

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.529483

1-sigma variation

Unit

MOID

Value

0.000274

1-sigma variation

Unit

Orbit Period

Value

1006.5476

1-sigma variation

Unit

U parameter

Value

7.1

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	5.08689E-7	1.10638E-7	7.17174E-7	5.03803E-6	-4.76300E-6	-1.96375E-4
e	1.10638E-7	2.40633E-8	1.55983E-7	1.09575E-6	-1.03591E-6	-4.27107E-5
i	7.17174E-7	1.55983E-7	1.01125E-6	7.10277E-6	-6.71472E-6	-2.76859E-4
Ω	5.03803E-6	1.09575E-6	7.10277E-6	4.98965E-5	-4.71726E-5	-1.94489E-3
ω	-4.76300E-6	-1.03591E-6	-6.71472E-6	-4.71726E-5	4.46026E-5	1.83871E-3
M	-1.96375E-4	-4.27107E-5	-2.76859E-4	-1.94489E-3	1.83871E-3	7.58087E-2

Date of computation: 2025-07-29 02:36 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

25.225

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

24 - 50*

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

1580

Unit

Source

[1]

Normalized RMS of residuals

Value

0.82387

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-04-03.362502

Unit

Source

[2]

Last Observation

Value

2021-04-17.891717

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

44 (2)

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 2021GX9 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	1958-04-22 00:59	> 1 d	0.0625463	0.0200920	0.0142040
EARTH	1969-04-05 00:44	> 1 d	0.1819623	0.0522675	0.0432758
EARTH	1977-09-20 16:23	> 1 d	0.1372097	0.0460892	0.0621617
EARTH	1988-08-30 10:50	> 1 w	0.1313397	0.0452199	0.0660278
EARTH	2021-04-18 06:36	< 1 s	0.0156897	0.0156787	0.0000037
EARTH	2032-04-22 19:23	> 1 d	0.0683182	0.0007236	0.0329552
EARTH	2043-04-24 06:57	> 1 d	0.0784398	0.0011502	0.0277960
EARTH	2054-04-27 18:49	698.7	0.1067903	0.0949935	0.0039323
EARTH	2109-09-01 00:52	> 1 w	0.1398759	0.0383004	0.0473863
EARTH	2120-09-07 17:09	> 1 d	0.0922502	0.0393889	0.0294629

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
322.07488406	104.05027197	0.00027420	MINIMUM
38.40022469	248.07507668	0.04491899	MINIMUM
0.52458121	176.64882506	0.27628590	SADDLE
0.17766438	355.91753352	1.72914138	SADDLE
180.08014341	355.69846679	2.20431516	SADDLE
179.99993921	175.66048166	4.19920516	MAXIMUM

Download:

MOID Plots

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

Level lines of the squared distance function

2021GX9

Date in UTC	MJD	σ	σ_imp	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS	TS
2032-04-16.911	63338.911	-1.982	0.000	1.14 ± 0.000	8.45E2	5.03E-5	1.52E0	-3.49	0


Based on 44 optical observations (of which 2 are rejected as outliers) from 2021/04/03.363 to 2021/04/17.892.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.20 and 1.20 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: