Asteroids

2021GL4 help

Last update: 2025-04-09 07:59 UTC

Orbital Properties

Epoch

60800.0

MJD

Orbit type

Apollo

Perihelion (q)

0.968

Aphelion (Q)

3.934

Eccentricity (e)

0.605

Inclination (i)

0.6

deg

Orbit period (P)

1401.4

Earth MOID

0.00801

U parameter

8.4

Next Earth close approach

Date

2044-04-07

Nominal distance (from Earth center)

0.01006

1505297

Maximum Brightness

mag

Risk

Object is not in risk list

Object is not in priority list

Physical Properties

Absolute Magnitude (H)

27.5

mag

Diameter

8 - 19*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-04-07

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

60800.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

2.450795

1-sigma variation

0.007955

Unit

Eccentricity (e)

Value

0.605075

1-sigma variation

0.001509

Unit

Inclination (i)

Value

0.5953

1-sigma variation

0.0011

Unit

Long. of Ascending Node (Ω)

Value

124.4374

1-sigma variation

0.0514

Unit

Arg. of Perihelion (ω)

Value

101.3379

1-sigma variation

0.0403

Unit

Mean Anomaly (M)

Value

15.08277

1-sigma variation

1.90046

Unit

Perihelion distance

Value

0.967879

1-sigma variation

Unit

Aphelion distance

Value

3.933710

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.786962

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.368063

1-sigma variation

Unit

MOID

Value

0.008011

1-sigma variation

Unit

Orbit Period

Value

1401.3893

1-sigma variation

Unit

U parameter

Value

8.4

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	6.32753E-5	1.20000E-5	8.57077E-6	3.67267E-4	-2.58393E-4	-1.51174E-2
e	1.20000E-5	2.27578E-6	1.62531E-6	6.96181E-5	-4.89683E-5	-2.86697E-3
i	8.57077E-6	1.62531E-6	1.16695E-6	5.14999E-5	-3.68553E-5	-2.04767E-3
Ω	3.67267E-4	6.96181E-5	5.14999E-5	2.64265E-3	-2.04051E-3	-8.77427E-2
ω	-2.58393E-4	-4.89683E-5	-3.68553E-5	-2.04051E-3	1.62762E-3	6.17310E-2
M	-1.51174E-2	-2.86697E-3	-2.04767E-3	-8.77427E-2	6.17310E-2	3.61175E0

Date of computation: 2025-04-09 07:59 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

27.507

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

8 - 19*

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

1550

Unit

Source

[1]

Normalized RMS of residuals

Value

0.75268

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-04-06.29058

Unit

Source

[2]

Last Observation

Value

2021-04-08.84933

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

17 (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 2021GL4 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	2021-04-11 16:01	< 1 min	0.0208029	0.0206817	0.0000404
EARTH	2044-04-07 06:43	> 1 mo	0.0100623	0.0098811	0.0935881
EARTH	2063-05-13 09:45	> 1 mo	0.0545155	0.0001064	5.0820583
EARTH	2082-06-28 13:44	> 1 mo	0.1592434	0.0059992	21.3892995
EARTH	2109-05-16 13:01	> 1 mo	0.0127454	0.0099263	5.3184434

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
14.29897782	151.76841835	0.00805009	MINIMUM
347.82846725	98.63521890	0.01012060	MINIMUM
1.04947018	125.14070564	0.04145584	SADDLE
1.07056380	305.19993412	1.95886870	SADDLE
180.26659443	304.19143534	2.94541053	SADDLE
180.27261611	124.19832565	4.94443620	MAXIMUM

Download:

MOID Plots

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