Asteroids

2021PJ1 help

Last update: 2025-05-21 08:47 UTC

Orbital Properties

Epoch

60800.0

MJD

Orbit type

Apollo

Perihelion (q)

0.796

Aphelion (Q)

1.627

Eccentricity (e)

0.343

Inclination (i)

0.4

deg

Orbit period (P)

487.0

Earth MOID

0.00568

U parameter

4.7

Next Earth close approach

Date

2025-08-15

Nominal distance (from Earth center)

0.01123

1679992

Maximum Brightness

18.6

mag

Risk

Object is not in risk list

Object is not in priority list

Physical Properties

Absolute Magnitude (H)

25.8

mag

Diameter

19 - 40*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-08-04

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

1.211408

1-sigma variation

0.000006

Unit

Eccentricity (e)

Value

0.342989

1-sigma variation

0.000006

Unit

Inclination (i)

Value

0.3696

1-sigma variation

8.090E-6

Unit

Long. of Ascending Node (Ω)

Value

232.6386

1-sigma variation

0.0015

Unit

Arg. of Perihelion (ω)

Value

169.6396

1-sigma variation

0.0015

Unit

Mean Anomaly (M)

Value

240.40912

1-sigma variation

0.00745

Unit

Perihelion distance

Value

0.795908

1-sigma variation

Unit

Aphelion distance

Value

1.626909

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.601395

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.189581

1-sigma variation

Unit

MOID

Value

0.005684

1-sigma variation

Unit

Orbit Period

Value

487.0060

1-sigma variation

Unit

U parameter

Value

4.7

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.02579E-11	3.61701E-11	5.04771E-11	4.38173E-9	-4.37342E-9	-4.72541E-8
e	3.61701E-11	3.26233E-11	4.57471E-11	4.17476E-9	-4.14648E-9	-4.24594E-8
i	5.04771E-11	4.57471E-11	6.54416E-11	7.23194E-9	-7.15529E-9	-5.92612E-8
Ω	4.38173E-9	4.17476E-9	7.23194E-9	2.38586E-6	-2.34492E-6	-5.15054E-6
ω	-4.37342E-9	-4.14648E-9	-7.15529E-9	-2.34492E-6	2.30742E-6	5.14019E-6
M	-4.72541E-8	-4.24594E-8	-5.92612E-8	-5.15054E-6	5.14019E-6	5.54662E-5

Date of computation: 2025-05-21 08:47 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

25.762

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

19 - 40*

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

1400

Unit

Source

[1]

Normalized RMS of residuals

Value

0.584678

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2021-08-04.380677

Unit

Source

[2]

Last Observation

Value

2021-08-14.82551

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

79 (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

2021-08-14

Unit

Source

[3]

Last Observation

Value

2021-08-14

Unit

Source

[3]

Delay (Discarded)

Value

0 (0)

Unit

Source

[-]

Doppler (Discarded)

Value

1 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

1 (0)

Unit

Source

[1]

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
[3]	JPL Radar Observations	Jet Propulsion Laboratory: https://ssd.jpl.nasa.gov/dat/radar_data_ast.txt

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 2021PJ1 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	1953-08-20 22:36	> 1 d	0.0518927	0.0069394	0.0438490
EARTH	1957-08-16 17:03	> 1 d	0.0120653	0.0074581	0.0173756
EARTH	1961-08-22 06:04	> 1 d	0.0612757	0.0078359	0.0354900
EARTH	1965-09-07 07:45	> 1 w	0.1243651	0.0404262	0.0281525
EARTH	1969-09-28 11:02	> 1 w	0.1660775	0.1259104	0.0134138
EARTH	1973-10-15 14:51	> 1 w	0.1874369	0.1728017	0.0048905
EARTH	1977-11-02 03:05	> 1 w	0.1952726	0.1949388	0.0001180
EARTH	1981-11-20 05:09	> 1 d	0.1868760	0.1826673	0.0014063
EARTH	1985-12-10 22:40	1070.9	0.1579889	0.1553897	0.0008669
EARTH	1990-01-04 17:01	> 1 d	0.1009784	0.0720718	0.0096408
EARTH	1994-01-16 01:06	> 1 d	0.0342474	0.0053045	0.0177176
EARTH	1998-01-18 17:01	146.3	0.0065750	0.0052745	0.0007579
EARTH	2001-12-30 15:22	513.7	0.1168871	0.1139845	0.0009676
EARTH	2005-11-26 06:44	658.3	0.1820287	0.1812037	0.0002750
EARTH	2009-10-30 14:29	482.4	0.1976973	0.1976722	0.0000084
EARTH	2013-10-03 07:58	284.8	0.1770481	0.1766304	0.0001392
EARTH	2017-08-30 19:22	74.0	0.1093479	0.1088269	0.0001737
EARTH	2021-08-15 04:41	< 1 s	0.0111143	0.0111137	0.0000002
EARTH	2025-08-15 04:42	24.0	0.0112301	0.0107556	0.0001599
EARTH	2029-08-31 16:55	148.7	0.1108787	0.1099104	0.0003228
MARS	2033-05-30 21:57	108.3	0.0448870	0.0432498	0.0005545
EARTH	2033-10-04 22:47	715.0	0.1771663	0.1762087	0.0003192
EARTH	2037-10-31 08:16	1202.9	0.1947948	0.1947742	0.0000069
EARTH	2041-11-26 15:50	> 1 d	0.1775895	0.1753819	0.0007359
EARTH	2045-12-29 19:47	1223.8	0.1132430	0.1059651	0.0024263
EARTH	2050-01-16 04:50	362.3	0.0147624	0.0075824	0.0027164
EARTH	2054-01-16 21:19	1387.1	0.0088083	0.0061114	0.0085288
EARTH	2057-12-25 07:43	> 1 w	0.1263757	0.0625589	0.0213618
EARTH	2061-11-20 03:52	> 1 w	0.1871005	0.1583169	0.0096734
EARTH	2065-10-22 08:43	> 1 w	0.1965192	0.1829201	0.0046355
EARTH	2069-09-20 17:08	> 1 w	0.1599102	0.0686884	0.0307577
EARTH	2073-08-19 08:22	> 1 w	0.0644935	0.0070274	0.0640637
EARTH	2077-08-10 02:28	> 1 d	0.0349075	0.0050663	0.0457678
EARTH	2081-08-01 02:40	> 1 d	0.1898355	0.0659895	0.0414047
MARS	2087-11-29 20:29	> 1 mo	0.0282905	0.0272165	0.0268918
EARTH	2107-01-27 02:07	> 1 w	0.1297699	0.0061071	0.5053227
EARTH	2111-01-18 07:34	> 1 mo	0.0112696	0.0060871	0.3734708
EARTH	2114-11-23 02:40	> 1 mo	0.1870804	0.0057532	0.4767892
EARTH	2118-09-29 17:14	> 1 mo	0.1744907	0.0101522	1.4625758
EARTH	2122-08-11 04:51	> 1 mo	0.0299152	0.0054664	5.8968508

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
56.84179019	15.25428373	0.00568369	MINIMUM
298.60656999	219.99234298	0.00646889	MINIMUM
357.14433417	297.00404040	0.19616664	SADDLE
178.60318030	118.56055062	0.61904296	SADDLE
357.10810190	116.96811163	1.80357734	SADDLE
178.62771330	298.58572850	2.61878537	MAXIMUM

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MOID Plots

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