Asteroids

88710 2001SL9 help

Last update: 2026-08-22 13:15 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.775

Aphelion (Q)

1.348

Eccentricity (e)

0.270

Inclination (i)

21.9

deg

Orbit period (P)

399.5

Earth MOID

0.19721

U parameter

0.0

Next Earth close approach

Date

2084-04-17

Nominal distance (from Earth center)

0.19929

29812709

Maximum Brightness

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

17.6

mag

Diameter

700

Taxonomic type

Rotation period (T)

2.400

Discovery Information

Discovery Date

2001-09-18

Observatory

Palomar Mountain/NEAT

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

1.061474

1-sigma variation

5.801E-10

Unit

Eccentricity (e)

Value

0.270109

1-sigma variation

2.587E-8

Unit

Inclination (i)

Value

21.9001

1-sigma variation

4.162E-6

Unit

Long. of Ascending Node (Ω)

Value

202.8158

1-sigma variation

4.291E-6

Unit

Arg. of Perihelion (ω)

Value

329.3446

1-sigma variation

7.611E-6

Unit

Mean Anomaly (M)

Value

64.10525

1-sigma variation

0.00001

Unit

Perihelion distance

Value

0.774760

1-sigma variation

Unit

Aphelion distance

Value

1.348188

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.203839

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.284398

1-sigma variation

Unit

MOID

Value

0.197207

1-sigma variation

Unit

Orbit Period

Value

399.4502

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	3.36497E-19	3.17152E-18	3.42944E-17	2.14538E-17	-6.42943E-16	2.54872E-16
e	3.17152E-18	6.69099E-16	3.03033E-14	-8.50531E-16	-2.27177E-14	5.68529E-14
i	3.42944E-17	3.03033E-14	1.73209E-11	-4.47050E-12	1.29164E-12	5.57197E-12
Ω	2.14538E-17	-8.50531E-16	-4.47050E-12	1.84162E-11	-1.76308E-11	7.99843E-13
ω	-6.42943E-16	-2.27177E-14	1.29164E-12	-1.76308E-11	5.79284E-11	-5.71430E-11
M	2.54872E-16	5.68529E-14	5.57197E-12	7.99843E-13	-5.71430E-11	8.41215E-11

Date of computation: 2026-08-22 13:15 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

2.400

Unit

Source

[3]

Quality

Value

3,B

Unit

Source

[3]

Amplitude

Value

0.08

Unit

mag

Source

[3]

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]

Taxonomy (all)

Value

Sr;Q

Unit

Source

[2]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

17.636

18.07

Unit

mag

Source

[4]

[5]

Slope Parameter (G)

Value

0.46

0.15**

Unit

Source

[5]

[4]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.18

Unit

Source

[6]

Diameter

Value

700

Unit

Source

[6]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

Unit

mag

Source

[-]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Visual S

Unit

Source

[7]

Satellites

Satellites

Value

Unit

Source

Satellites

Value

Binary Child 1

Unit

Source

[8]

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Sources

No.	Name	Additional
[1]	EARN	1.) Lazzarin, M. et al. (2004) Icarus 169, 373-384. (Visible and near-infrared spectroscopic investigation of near-Earth objects at ESO: first results)
[2]	EARN	1.) Lazzarin, M. et al. (2004) Icarus 169, 373-384. (Visible and near-infrared spectroscopic investigation of near-Earth objects at ESO: first results) 2.) Lazzarin, M., Marchi,S. & Magrin, S. (2010) href="http://www.astro.unipd.it/planets/sineo/data.html"> SINEO Database (Spectroscopic Investiation of Near-Earth Objects)
[3]	EARN	1.) Pravec, P. et al. (2006) Icarus 181, 63-93. (Photometric survey of binary near-Earth asteroids) 2.) Petr Pravec's Ondrejov NEO Photometric Program Webpage "Prepublished Periods" 3.) Pravec, P. et al. (2001) I.A.U. Circ. HREF="http://www.cbat.eps.harvard.edu/iauc/07700/07742.html"> 7742. (2001 SL9) (binary asteroid, complex lightcurve) 4.) Warner, B.D. (2014) MPB 41,113-124. (NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT CS3-PALMER DIVIDE STATION: 2013 SEPTEMBER-DECEMBER)(LCs of 36 NEAs)
[4]	ESA Aegis	ESA orbit determination and impact monitoring system
[5]	EARN	1.) Pravec, P. et al. (2012) Icarus 221, 365-387 (Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations)
[6]	EARN	1.) Nugent, C.R. et al. (2016) Astron. J. 152_63 (12pp) (NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos) (207 NEOs)
[7]	EARN	1.) Lazzarin, M. et al. (2004) Icarus 169, 373-384. (Visible and near-infrared spectroscopic investigation of near-Earth objects at ESO: first results) 2.) Lazzarin, M., Marchi,S. & Magrin, S. (2010) href="http://www.astro.unipd.it/planets/sineo/data.html"> SINEO Database (Spectroscopic Investiation of Near-Earth Objects) 3.) deLeon, J. et al. (2010) Astron. Astrophys 517, A23. (Observations, compositional, and physical characterization of near-Earth and Mars-crosser asteroids from a spectroscopic survey)
[8]	EARN	Earth Asteroids Research Node: https://earn.dlr.de

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

26201

Unit

Source

[1]

Unobserved

Value

Unit

Source

[1]

Normalized RMS of residuals

Value

0.406527

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1954-11-27.18819

Unit

Source

[2]

Last Observation

Value

2026-08-21.938032

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

2357 (12)

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

Filters

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Final Date: *

Normalised Only accepted

Max residual (arcsec):

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Plot

Computation parameters

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Initial Date: *

Final Date: *

Output option:

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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 88710 2001SL9 from 1950 to 2126

Body	Date in UTC	Time uncert. in min	Nominal distance in au	Min. possible distance in au
EARTH	1979-04-20 09:11	< 1 min	0.1976669	0.1976668
EARTH	2026-04-26 23:19	< 1 min	0.1994931	0.1994930
EARTH	2084-04-17 13:46	< 1 min	0.1992857	0.1992856

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
31.28028579	106.46678969	0.19720677	MINIMUM
246.07550918	299.51165064	0.23892701	MINIMUM
317.54839920	13.60944946	0.37103860	SADDLE
138.65100461	218.10964713	0.46403019	SADDLE
355.92491635	243.25813591	1.77219270	SADDLE
187.08624661	75.43824446	2.33443526	MAXIMUM

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MOID Plots

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