Asteroids

277475 2005WK4 help

Last update: 2026-07-30 09:40 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.771

Aphelion (Q)

1.250

Eccentricity (e)

0.237

Inclination (i)

9.8

deg

Orbit period (P)

371.0

Earth MOID

0.00327

U parameter

0.0

Next Earth close approach

Date

2067-01-17

Nominal distance (from Earth center)

0.11328

16946880

Maximum Brightness

18.9

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

20.1

mag

Diameter

260 - 600*

Taxonomic type

Rotation period (T)

2.595

Discovery Information

Discovery Date

2005-11-27

Observatory

Siding Spring 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

61200.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.010544

1-sigma variation

2.513E-9

Unit

Eccentricity (e)

Value

0.237300

1-sigma variation

4.927E-8

Unit

Inclination (i)

Value

9.8438

1-sigma variation

3.783E-6

Unit

Long. of Ascending Node (Ω)

Value

138.1080

1-sigma variation

4.069E-6

Unit

Arg. of Perihelion (ω)

Value

74.1264

1-sigma variation

6.605E-6

Unit

Mean Anomaly (M)

Value

305.45805

1-sigma variation

0.00002

Unit

Perihelion distance

Value

0.770742

1-sigma variation

Unit

Aphelion distance

Value

1.250346

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.090698

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.005865

1-sigma variation

Unit

MOID

Value

0.003273

1-sigma variation

Unit

Orbit Period

Value

371.0489

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	6.31500E-18	1.00735E-16	-6.81110E-15	1.94846E-15	-5.61879E-15	-5.64668E-14
e	1.00735E-16	2.42789E-15	-1.65306E-13	5.25148E-16	-7.45184E-14	-9.95685E-13
i	-6.81110E-15	-1.65306E-13	1.43117E-11	-5.30688E-13	4.92306E-12	6.81453E-11
Ω	1.94846E-15	5.25148E-16	-5.30688E-13	1.65568E-11	-2.60330E-11	-5.36425E-12
ω	-5.61879E-15	-7.45184E-14	4.92306E-12	-2.60330E-11	4.36293E-11	3.44946E-11
M	-5.64668E-14	-9.95685E-13	6.81453E-11	-5.36425E-12	3.44946E-11	5.21154E-10

Date of computation: 2026-07-30 09:40 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

2.595

Unit

Source

[4]

Quality

Value

Unit

Source

[4]

Amplitude

Value

0.36

Unit

mag

Source

[4]

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

[1]

[2]

Taxonomy (all)

Value

Unit

Source

[1]

[3]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

20.09

20.07

Unit

mag

Source

[1]

[5]

Slope Parameter (G)

Value

0.15**

0.15

Unit

Source

[5]

[1]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[6]

Diameter

Value

260 - 600*

Unit

Source

[6]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

0.45

0.67

0.3

Unit

V-R

B-V

R-I

Source

[1]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Visual S

Radar R

Unit

Source

[7]

[8]

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Sources

No.	Name	Additional
[1]	EARN	1.) Hicks, M. et al. (2013) href="http://www.astronomerstelegram.org/?read=5311"> ATel#5311 (Broadband Photometry Of The Potentially Asteroid 277475 (2005 WK4) and Corrected 52762 (1998 MT24) Colors.)
[2]	EARN	1.) Alexey V. Sergeyev and Benoit Carry A&A, 652 (2021) A59
[3]	EARN	Earth Asteroids Research Node: https://earn.dlr.de
[4]	EARN	1.) Stephens, R.D. (2014) MPB 41, 13-15. (ASTEROIDS OBSERVED FROM CS3:2013 JULY-SEPTEMBER) (..,277475)
[5]	ESA Aegis	ESA orbit determination and impact monitoring system
[6]	Estimation	Estimated from absolute magnitude
[7]	EARN	1.) Lim, L.F. et al. (2014) LPSC 45, 1695. (Thermal Emission Photometry of Three Near-Earth Asteroids in L' and M')(163249,277475,137126)
[8]	EARN	1.) href="http://echo.jpl.nasa.gov/asteroids/index.html">JPL's NEO Radar Detection Program Webpage

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

3563

Unit

Source

[1]

Unobserved

Value

4039

Unit

Source

[1]

Normalized RMS of residuals

Value

0.623022

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2005-11-27.63813

Unit

Source

[2]

Last Observation

Value

2015-08-30.161109

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

325 (7)

Unit

Source

[1]

Radar Summary

First Observation
Last Observation
Delay (Discarded)
Doppler (Discarded)
Total Optical Observations (Discarded)

Radar

Value

Unit

Source

First Observation

Value

2012-07-23

Unit

Source

[3]

Last Observation

Value

2013-08-09

Unit

Source

[3]

Delay (Discarded)

Value

9 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

3 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

12 (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

Filters

Initial Date: *

Final Date: *

Normalised Only accepted

Max residual (arcsec):

* - these fields are required

Plot

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

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Note: Ephemerides requests are limited to a maximum of 1000 points and a final date not exceeding 2040/12/31 00:00.

Close Approaches for 277475 2005WK4 from 1950 to 2126

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au	Distance uncert. in au
EARTH	1954-08-13 17:56	< 1 min	0.1565556	0.1565502	0.0000018
EARTH	1955-08-08 18:43	< 1 s	0.0678695	0.0678694	0.0000000
EARTH	1956-08-09 23:29	< 1 min	0.0186666	0.0186612	0.0000018
EARTH	1957-08-14 04:41	< 1 min	0.1269653	0.1269597	0.0000019
EARTH	2003-01-12 19:05	< 1 min	0.1949606	0.1949600	0.0000002
EARTH	2004-01-18 23:25	< 1 min	0.0945194	0.0945190	0.0000001
EARTH	2005-01-25 14:17	< 1 min	0.0602349	0.0602347	0.0000001
EARTH	2006-02-10 17:34	< 1 min	0.1412550	0.1412547	0.0000001
EARTH	2012-08-09 00:35	< 1 s	0.1282872	0.1282871	0.0000000
EARTH	2013-08-09 05:01	< 1 s	0.0207131	0.0207130	0.0000000
EARTH	2014-08-12 11:26	< 1 s	0.0720403	0.0720402	0.0000000
EARTH	2015-08-16 12:00	< 1 s	0.1687526	0.1687524	0.0000001
EARTH	2067-01-17 06:20	< 1 min	0.1132829	0.1132779	0.0000017
EARTH	2068-01-23 10:44	< 1 min	0.0540370	0.0540365	0.0000002
EARTH	2069-01-31 21:28	< 1 min	0.1010041	0.1009993	0.0000016
EARTH	2070-02-22 11:36	< 1 min	0.1767527	0.1767484	0.0000015
EARTH	2076-08-15 12:41	< 1 min	0.1696055	0.1695994	0.0000020
EARTH	2077-08-08 04:38	< 1 min	0.0778291	0.0778226	0.0000022
EARTH	2078-08-10 13:56	< 1 min	0.0127854	0.0127794	0.0000020
EARTH	2079-08-15 09:21	< 1 min	0.1328391	0.1328310	0.0000027
EARTH	2121-01-15 10:17	11.9	0.1729039	0.1723678	0.0001787
EARTH	2122-01-22 08:37	16.9	0.0668179	0.0664382	0.0001271
EARTH	2123-02-01 02:51	31.1	0.0869904	0.0865336	0.0001525
EARTH	2124-02-27 13:23	95.3	0.1836665	0.1832710	0.0001319

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
91.28741510	213.33767149	0.00327335	MINIMUM
283.99167188	18.01270653	0.05468120	MINIMUM
8.19025762	117.04770283	0.27885215	SADDLE
187.07536687	293.94423382	0.31686890	SADDLE
5.31968345	293.32612096	1.75884303	SADDLE
182.25212226	110.13009481	2.24812874	MAXIMUM

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MOID Plots

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