Asteroids

2021GW2 help

Last update: 2025-11-24 16:53 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.864

Aphelion (Q)

3.414

Eccentricity (e)

0.596

Inclination (i)

23.4

deg

Orbit period (P)

1142.6

Earth MOID

0.04492

U parameter

8.5

Next Earth close approach

Date

2046-04-26

Nominal distance (from Earth center)

0.17838

26685419

Maximum Brightness

23.7

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

24.6

mag

Diameter

30 - 70*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-04-05

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

2.138933

1-sigma variation

0.006496

Unit

Eccentricity (e)

Value

0.595970

1-sigma variation

0.001302

Unit

Inclination (i)

Value

23.4416

1-sigma variation

0.0340

Unit

Long. of Ascending Node (Ω)

Value

20.0838

1-sigma variation

0.0007

Unit

Arg. of Perihelion (ω)

Value

240.7407

1-sigma variation

0.0205

Unit

Mean Anomaly (M)

Value

156.84315

1-sigma variation

2.35701

Unit

Perihelion distance

Value

0.864194

1-sigma variation

Unit

Aphelion distance

Value

3.413672

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.948085

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.064932

1-sigma variation

Unit

MOID

Value

0.044919

1-sigma variation

Unit

Orbit Period

Value

1142.6000

1-sigma variation

Unit

U parameter

Value

8.5

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.22025E-5	8.46091E-6	2.21149E-4	4.79232E-6	-1.33118E-4	-1.53120E-2
e	8.46091E-6	1.69628E-6	4.43369E-5	9.60784E-7	-2.66880E-5	-3.06980E-3
i	2.21149E-4	4.43369E-5	1.15887E-3	2.51121E-5	-6.97563E-4	-8.02377E-2
Ω	4.79232E-6	9.60784E-7	2.51121E-5	5.44289E-7	-1.51163E-5	-1.73876E-3
ω	-1.33118E-4	-2.66880E-5	-6.97563E-4	-1.51163E-5	4.19895E-4	4.82980E-2
M	-1.53120E-2	-3.06980E-3	-8.02377E-2	-1.73876E-3	4.82980E-2	5.55551E0

Date of computation: 2025-11-24 16:53 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

24.606

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

30 - 70*

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

1693

Unit

Source

[1]

Normalized RMS of residuals

Value

0.408502

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-04-05.305947

Unit

Source

[2]

Last Observation

Value

2021-04-16.374289

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

47 (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 2021GW2 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	1971-04-24 07:50	> 1 mo	0.1420240	0.0331774	0.9379051
EARTH	1996-04-19 07:42	> 1 mo	0.0903876	0.0373204	0.6578094
EARTH	2021-04-16 00:11	< 1 s	0.0533440	0.0530897	0.0000848
EARTH	2046-04-26 09:06	> 1 mo	0.1783810	0.0289088	0.6870782

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
329.93604026	101.11277850	0.04488490	MINIMUM
38.45340358	231.18832124	0.35482811	MINIMUM
13.94304870	185.85071009	0.40554733	SADDLE
3.08548051	342.52649766	1.81725789	SADDLE
182.27645837	337.73008053	2.51427492	SADDLE
178.84571447	155.94077847	4.37985204	MAXIMUM

Download:

MOID Plots

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