Asteroids

2021PW4

Last update: 2023-06-03 23:50 UTC

Orbital Properties

Epoch

60000.0

MJD

Orbit type

Apollo

Perihelion (q)

1.010

Aphelion (Q)

2.275

Eccentricity (e)

0.385

Inclination (i)

1.2

deg

Orbit period (P)

768.7

Earth MOID

0.01950

U parameter

6.8

Next Earth close approach

Date

2061-06-26

Nominal distance (from Earth center)

0.0211

3156782

Maximum Brightness

119.7

mag

Risk

Object is not in risk list

Object is not in priority list

Physical Properties

Absolute Magnitude (H)

24.9

mag

Diameter

40*

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

2021-08-07

Observatory

ATLAS-MLO, Mauna Loa

Orbit Visualiser

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External links

Proper elements

Epoch

Near present day

Near middle of observation arc

Orbit properties

Epoch
Semimajor Axis
Eccentricity (e)
Inclination (i)
Ascending Node (Ω)
Arg. of Perihelion (ω)
Mean Anomaly (M)
Perihelion
Aphelion
Asc. Node-Earth Sep.
Desc. Node-Earth Sep.
MOID
Orbit Period
U parameter

Value

1-sigma variation

Unit

Epoch

Value

60000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.642209

1-sigma variation

0.000331

Unit

Eccentricity (e)

Value

0.385151

1-sigma variation

0.000125

Unit

Inclination (i)

Value

1.1975

1-sigma variation

0.0003

Unit

Ascending Node (Ω)

Value

188.3916

1-sigma variation

0.0010

Unit

Arg. of Perihelion (ω)

Value

99.8153

1-sigma variation

0.0004

Unit

Mean Anomaly (M)

Value

276.30669

1-sigma variation

0.08380

Unit

Perihelion

Value

1.009710

1-sigma variation

Unit

Aphelion

Value

2.274709

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.498854

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.310131

1-sigma variation

Unit

MOID

Value

0.019500

1-sigma variation

Unit

Orbit Period

Value

768.6723

1-sigma variation

Unit

U parameter

Value

6.8

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.09716E-7	4.13094E-8	1.12094E-7	-3.18490E-7	1.03915E-7	-2.77558E-5
e	4.13094E-8	1.55536E-8	4.22042E-8	-1.19894E-7	3.90955E-8	-1.04504E-5
i	1.12094E-7	4.22042E-8	1.14572E-7	-3.27048E-7	1.08101E-7	-2.83577E-5
Ω	-3.18490E-7	-1.19894E-7	-3.27048E-7	9.91410E-7	-3.76421E-7	8.05742E-5
ω	1.03915E-7	3.90955E-8	1.08101E-7	-3.76421E-7	1.84564E-7	-2.62924E-5
M	-2.77558E-5	-1.04504E-5	-2.83577E-5	8.05742E-5	-2.62924E-5	7.02167E-3

Date of computation: 2023-05-08 23:51 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

24.926

Unit

mag

Source

[1]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

Unit

Source

[-]

Diameter

Value

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

[-]

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Sources

No.	Name	Additional
[1]	ESA ODIM	ESA orbit determination and impact monitoring system
[2]	Estimation	Estimated from absolute magnitude

Observational Information

Arc Length
Unobserved

Arc Information

Value

Unit

Source

Arc Length

Value

Unit

Source

[1]

Unobserved

Value

632

Unit

Source

[1]

Astrometry Summary

RMS of Residuals
First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

RMS of Residuals

Value

0.496522

Unit

arcsec

Source

[1]

First Observation

Value

2021-08-07.460024

Unit

Source

[2]

Last Observation

Value

2021-09-10.37684

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

85 (1)

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

[3]

Last Observation

Value

Unit

Source

[3]

Delay (Discarded)

Value

0 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

0 (0)

Unit

Source

[1]

Note: The ASCII file is in a format suitable for Orbfit input.

Sources

No.	Name	Additional
[1]	ESA ODIM	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 2021PW4 from 1950 to 2123

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possibile distance in au	Distance uncert. in au
EARTH	1956-06-09 20:46	> 1 w	0.0428287	0.0207366	0.0291744
EARTH	1977-06-01 15:11	> 1 d	0.0897289	0.0205725	0.0410290
EARTH	2000-08-23 08:09	> 1 d	0.1575293	0.0464413	0.0376059
EARTH	2021-08-04 15:10	< 1 min	0.0294722	0.0294475	0.0000082
EARTH	2061-06-26 14:30	> 1 w	0.0211018	0.0211004	0.0001996
EARTH	2082-08-11 02:35	> 1 mo	0.0481857	0.0179789	0.3877356
EARTH	2101-06-13 18:18	> 1 mo	0.0406375	0.0215752	0.7471318
EARTH	2122-07-22 11:51	> 1 mo	0.0196020	0.0183942	0.1035162

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