Asteroids

2021VR4 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.918

Aphelion (Q)

2.173

Eccentricity (e)

0.406

Inclination (i)

0.7

deg

Orbit period (P)

702.0

Earth MOID

0.00341

U parameter

6.9

Next Earth close approach

Date

2045-02-28

Nominal distance (from Earth center)

0.14512

21709104

Maximum Brightness

24.7

mag

Risk

Object is in risk list

Physical Properties

Absolute Magnitude (H)

26.3

mag

Diameter

15 - 30*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-11-07

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.545889

1-sigma variation

0.000296

Unit

Eccentricity (e)

Value

0.405916

1-sigma variation

0.000127

Unit

Inclination (i)

Value

0.6673

1-sigma variation

0.0001

Unit

Long. of Ascending Node (Ω)

Value

258.5743

1-sigma variation

0.0035

Unit

Arg. of Perihelion (ω)

Value

203.7221

1-sigma variation

0.0023

Unit

Mean Anomaly (M)

Value

10.96104

1-sigma variation

0.21092

Unit

Perihelion distance

Value

0.918388

1-sigma variation

Unit

Aphelion distance

Value

2.173390

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

1.040482

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.043990

1-sigma variation

Unit

MOID

Value

0.003408

1-sigma variation

Unit

Orbit Period

Value

702.0465

1-sigma variation

Unit

U parameter

Value

6.9

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	8.77717E-8	3.74955E-8	2.03248E-8	1.02003E-6	-6.68092E-7	-6.24887E-5
e	3.74955E-8	1.60179E-8	8.68226E-9	4.35770E-7	-2.85422E-7	-2.66948E-5
i	2.03248E-8	8.68226E-9	4.73835E-9	2.34639E-7	-1.53329E-7	-1.44701E-5
Ω	1.02003E-6	4.35770E-7	2.34639E-7	1.19343E-5	-7.83434E-6	-7.26208E-4
ω	-6.68092E-7	-2.85422E-7	-1.53329E-7	-7.83434E-6	5.14725E-6	4.75649E-4
M	-6.24887E-5	-2.66948E-5	-1.44701E-5	-7.26208E-4	4.75649E-4	4.44886E-2

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

26.277

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

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

[-]

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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

1390

Unit

Source

[1]

Normalized RMS of residuals

Value

0.544781

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-11-07.261113

Unit

Source

[2]

Last Observation

Value

2021-11-23.876622

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

31 (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 2021VR4 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	1950-02-23 12:58	> 1 mo	0.0745969	0.0082207	2.7795644
MARS	1956-02-01 10:38	> 1 mo	0.0368576	0.0184225	1.0219664
MARS	1957-12-20 16:47	> 1 mo	0.0187323	0.0183413	0.1622037
MARS	1959-11-09 00:16	> 1 w	0.0428629	0.0181859	0.4739825
EARTH	1967-02-21 12:16	> 1 mo	0.0524445	0.0083967	0.7785413
EARTH	1985-11-08 21:21	> 1 mo	0.1288555	0.0041009	0.7580035
EARTH	2002-11-28 03:09	> 1 w	0.0168930	0.0034520	0.0269858
EARTH	2021-11-25 03:58	< 1 s	0.0054996	0.0054944	0.0000017
EARTH	2045-02-28 09:37	> 1 d	0.1451164	0.0245869	0.0407808
EARTH	2046-11-15 23:30	> 1 d	0.0578018	0.0036853	0.0396464
EARTH	2070-01-17 01:38	> 1 mo	0.0591401	0.0166849	0.0431085
MARS	2091-07-02 12:07	> 1 d	0.0335901	0.0200664	0.0330847
EARTH	2093-02-23 06:53	> 1 d	0.0794965	0.0107628	0.0414668
EARTH	2094-11-09 06:46	> 1 d	0.1359216	0.0619929	0.0246550
EARTH	2117-12-25 22:08	> 1 mo	0.0614585	0.0144274	0.0476183

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
332.91036957	320.00160509	0.00341858	MINIMUM
27.06688356	40.08855981	0.01031290	MINIMUM
0.10468909	0.21797332	0.06536034	SADDLE
180.00669593	180.06562917	1.15695596	SADDLE
0.00613675	180.06896747	1.93473324	SADDLE
179.99903447	0.06059616	3.15687950	MAXIMUM

Download:

MOID Plots

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

Level lines of the squared distance function

2021VR4

Date in UTC	MJD	σ	σ_imp	Distance ± Width in RE	Stretching in RE	IP	Impact energy	PS	TS
2098-11-25.306	87667.306	-3.567	0.000	0.71 ± 0.000	3.25E6	6.84E-10	1.46E-1	-10.18	0


Based on 31 optical observations (of which 0 are rejected as outliers) from 2021/11/07.261 to 2021/11/23.877.
Coordinates are given on the Target Plane.
Unit is one Earth radius, but impact cross section has radius between 1.75 and 1.75 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: