Asteroids

484976 2009UN3 help

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

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.988

Aphelion (Q)

3.668

Eccentricity (e)

0.576

Inclination (i)

37.4

deg

Orbit period (P)

1297.3

Earth MOID

0.02487

U parameter

0.0

Next Earth close approach

Date

2042-01-31

Nominal distance (from Earth center)

0.19641

29382409

Maximum Brightness

17.5

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

18.4

mag

Diameter

500 - 1200*

Taxonomic type

Rotation period (T)

4.123

Discovery Information

Discovery Date

2009-10-19

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

2.327838

1-sigma variation

1.062E-8

Unit

Eccentricity (e)

Value

0.575611

1-sigma variation

1.599E-8

Unit

Inclination (i)

Value

37.4343

1-sigma variation

1.278E-5

Unit

Long. of Ascending Node (Ω)

Value

141.9464

1-sigma variation

1.593E-6

Unit

Arg. of Perihelion (ω)

Value

338.7768

1-sigma variation

1.331E-5

Unit

Mean Anomaly (M)

Value

165.91214

1-sigma variation

0.00001

Unit

Perihelion distance

Value

0.987909

1-sigma variation

Unit

Aphelion distance

Value

3.667767

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.025411

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

2.345000

1-sigma variation

Unit

MOID

Value

0.024869

1-sigma variation

Unit

Orbit Period

Value

1297.2617

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	1.12776E-16	-3.68100E-17	-3.91517E-15	-1.59693E-15	5.12726E-14	-1.26810E-13
e	-3.68100E-17	2.55622E-16	1.30281E-14	7.83147E-15	-1.87905E-13	6.36689E-14
i	-3.91517E-15	1.30281E-14	1.63237E-10	-1.82819E-12	2.54591E-13	3.80506E-12
Ω	-1.59693E-15	7.83147E-15	-1.82819E-12	2.53758E-12	-2.19212E-12	1.46294E-12
ω	5.12726E-14	-1.87905E-13	2.54591E-13	-2.19212E-12	1.77148E-10	-7.79457E-11
M	-1.26810E-13	6.36689E-14	3.80506E-12	1.46294E-12	-7.79457E-11	1.45407E-10

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

4.123

Unit

Source

[5]

[6]

Quality

Value

Unit

Source

[6]

[5]

Amplitude

Value

0.5

Unit

mag

Source

[6]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

Unit

Source

[-]

Spinvector B

Value

Unit

Source

[-]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Scomp

Unit

Source

[1]

[2]

Taxonomy (all)

Value

Unit

Source

[3]

[4]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

18.422

18.63

Unit

mag

Source

[7]

[8]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[7]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[9]

Diameter

Value

500 - 1200*

Unit

Source

[9]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

0.77

0.46

Unit

B-V

V-R

Source

[10]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Radar R

Unit

Source

[11]

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Sources

No.	Name	Additional
[1]	EARN	1.) DeMeo, F.E. et al. (2014) Icarus 227, 112-122. (Mars encounters cause fresh surfaces on some near-Earth asteroids) (contains taxonomic classification of 249 NEAs)
[2]	EARN	1.) Alexey V. Sergeyev and Benoit Carry A&A, 652 (2021) A59
[3]	EARN	1.) Hicks, M. et al. (2010) href="http://www.astronomerstelegram.org/?read=2449"> ATel#2449 (Broadband Colors and Rotation Lightcurves of the Potentially Hazardous Asteroid 2009 UN3) 2.) Somers, J.M. et al. (2010) DPS 42, 1316. (abstract) (Optical Characterization Of Planetary Radar Targets, Low-deltaV, And Potentially Hazardous Asteroids: Results From 2009-2010) 3.) DeMeo, F.E. et al. (2014) Icarus 227, 112-122. (Mars encounters cause fresh surfaces on some near-Earth asteroids) (contains taxonomic classification of 249 NEAs)
[4]	EARN	Earth Asteroids Research Node: https://earn.dlr.de
[5]	EARN	1.) Hicks, M.; Barajas, T.; Shitanishi, J. (2010) Astronomer's Telegram 2449. http://www.astronomerstelegram.org.
[6]	EARN	1.) Hicks, M. et al. (2010) href="http://www.astronomerstelegram.org/?read=2449"> ATel#2449 (Broadband Colors and Rotation Lightcurves of the Potentially Hazardous Asteroid 2009 UN3) 2.) Polishook, D. (2012) MPB 39, 187-192. (LIGHTCURVES AND SPIN PERIODS OF NEAR-EARTH ASTEROIDS, THE WISE OBSERVATORY, 2005 - 2010) (1862,3361,5143,10115,40267,66251,68216,86829, 105140,138893,141432,141495,152931,185851,2009UN3)
[7]	ESA Aegis	ESA orbit determination and impact monitoring system
[8]	EARN	1.) Hicks, M. et al. (2010) href="http://www.astronomerstelegram.org/?read=2449"> ATel#2449 (Broadband Colors and Rotation Lightcurves of the Potentially Hazardous Asteroid 2009 UN3)
[9]	Estimation	Estimated from absolute magnitude
[10]	EARN	1.) Betzler, A. et al. (2010) MPB 37, 95-97. (Photometric Observations of the Near-Earth Asteroids 1999 AP10 2000 TO64, 2000 UJ1, 2000 XK44, 2001 MZ7, 2003 QO104, 2005 RQ6, 2005 WJ56, and 2009 UN3)
[11]	EARN	1.) href="http://echo.jpl.nasa.gov/asteroids/index.html">JPL's NEO Radar Detection Program Webpage 2.) Slade, M.A. et al. (2010) DPS 42, 5701. (abstract) (First Results Of The New Goldstone Delay-Doppler Radar Chirp Imaging System) (2009UN3,2010AL30)

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

5159

Unit

Source

[1]

Unobserved

Value

3123

Unit

Source

[1]

Normalized RMS of residuals

Value

0.409735

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

2003-03-07.483408

Unit

Source

[2]

Last Observation

Value

2017-04-21.15269

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

365 (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

2010-02-08

Unit

Source

[3]

Last Observation

Value

2010-02-09

Unit

Source

[3]

Delay (Discarded)

Value

4 (1)

Unit

Source

[1]

Doppler (Discarded)

Value

3 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

7 (1)

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 484976 2009UN3 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	1978-02-10 05:42	< 1 min	0.0199504	0.0199480	0.0000008
EARTH	2010-02-09 06:09	< 1 s	0.0366718	0.0366718	0.0000000
EARTH	2042-01-31 21:25	< 1 min	0.1964093	0.1964051	0.0000014

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
10.85332422	38.75356490	0.02522844	MINIMUM
352.16247703	189.32072915	1.98258488	SADDLE
175.82196988	200.84216589	2.69003815	SADDLE
182.22621758	23.63129611	4.63450067	MAXIMUM

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MOID Plots

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