Asteroids

2021HF1 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Amor

Perihelion (q)

1.039

Aphelion (Q)

1.565

Eccentricity (e)

0.202

Inclination (i)

1.4

deg

Orbit period (P)

542.5

Earth MOID

0.02675

U parameter

7.3

Next Earth close approach

Date

2070-06-02

Nominal distance (from Earth center)

0.05538

8284769

Maximum Brightness

23.3

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

27.6

mag

Diameter

8 - 18*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-04-16

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.301801

1-sigma variation

0.000378

Unit

Eccentricity (e)

Value

0.202159

1-sigma variation

0.000212

Unit

Inclination (i)

Value

1.3910

1-sigma variation

0.0013

Unit

Long. of Ascending Node (Ω)

Value

47.0647

1-sigma variation

0.0010

Unit

Arg. of Perihelion (ω)

Value

183.1661

1-sigma variation

0.0078

Unit

Mean Anomaly (M)

Value

18.23192

1-sigma variation

0.51960

Unit

Perihelion distance

Value

1.038630

1-sigma variation

Unit

Aphelion distance

Value

1.564972

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.573756

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.028174

1-sigma variation

Unit

MOID

Value

0.026746

1-sigma variation

Unit

Orbit Period

Value

542.5195

1-sigma variation

Unit

U parameter

Value

7.3

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.43011E-7	8.02558E-8	5.02072E-7	-3.74416E-7	2.92938E-6	-1.96495E-4
e	8.02558E-8	4.50386E-8	2.81758E-7	-2.10124E-7	1.64402E-6	-1.10270E-4
i	5.02072E-7	2.81758E-7	1.76277E-6	-1.31557E-6	1.02887E-5	-6.89843E-4
Ω	-3.74416E-7	-2.10124E-7	-1.31557E-6	9.93875E-7	-7.69521E-6	5.14451E-4
ω	2.92938E-6	1.64402E-6	1.02887E-5	-7.69521E-6	6.02071E-5	-4.02504E-3
M	-1.96495E-4	-1.10270E-4	-6.89843E-4	5.14451E-4	-4.02504E-3	2.69981E-1

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

27.629

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 - 18*

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

1643

Unit

Source

[1]

Normalized RMS of residuals

Value

0.527645

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-04-16.423972

Unit

Source

[2]

Last Observation

Value

2021-05-05.528466

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

22 (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 2021HF1 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
MARS	1954-10-23 23:07	> 1 d	0.0170381	0.0103373	0.0085005
EARTH	1957-06-15 18:36	> 1 d	0.1658049	0.0586725	0.0358123
EARTH	1960-05-27 23:34	> 1 w	0.0459448	0.0027623	0.0394746
EARTH	1963-05-04 05:32	> 1 w	0.0350494	0.0130045	0.0200672
EARTH	1966-04-13 06:45	> 1 d	0.1528448	0.0144423	0.0462533
EARTH	2018-06-08 01:25	> 1 d	0.0849268	0.0609599	0.0079944
EARTH	2021-05-07 09:16	< 1 min	0.0318473	0.0317505	0.0000323
EARTH	2024-04-11 20:42	596.3	0.1794456	0.1525704	0.0089588
MARS	2026-08-30 01:31	> 1 d	0.0476853	0.0187457	0.0096991
MARS	2054-11-16 11:52	> 1 w	0.0454015	0.0040721	0.0457108
EARTH	2070-06-02 09:37	> 1 w	0.0553803	0.0005457	0.0538659
EARTH	2073-04-28 10:45	> 1 d	0.0548905	0.0179398	0.0124122
EARTH	2122-06-05 00:43	> 1 mo	0.0588650	0.0018735	0.6198300
EARTH	2125-04-30 02:16	> 1 mo	0.0555209	0.0058046	0.1728950

Download as:

Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
2.68498955	130.58260170	0.02851196	MINIMUM
182.21337872	310.23391796	0.57543155	SADDLE
3.25363715	311.30225245	2.02815110	SADDLE
182.22884949	130.25600623	2.57521945	MAXIMUM

Download:

MOID Plots

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