Asteroids

85713 1998SS49 help

Last update: 2026-09-16 13:00 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.695

Aphelion (Q)

3.153

Eccentricity (e)

0.639

Inclination (i)

10.8

deg

Orbit period (P)

974.5

Earth MOID

0.00449

U parameter

0.0

Next Earth close approach

Date

2030-11-22

Nominal distance (from Earth center)

0.12538

18756350

Maximum Brightness

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

15.8

mag

Diameter

3484

Taxonomic type

Rotation period (T)

5.370

Discovery Information

Discovery Date

1998-09-29

Observatory

Lincoln Laboratory ETS, New Mexico

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

1.923672

1-sigma variation

6.911E-10

Unit

Eccentricity (e)

Value

0.638845

1-sigma variation

1.835E-8

Unit

Inclination (i)

Value

10.7844

1-sigma variation

3.001E-6

Unit

Long. of Ascending Node (Ω)

Value

40.9416

1-sigma variation

1.080E-5

Unit

Arg. of Perihelion (ω)

Value

103.1481

1-sigma variation

1.094E-5

Unit

Mean Anomaly (M)

Value

101.26122

1-sigma variation

1.866E-6

Unit

Perihelion distance

Value

0.694743

1-sigma variation

Unit

Aphelion distance

Value

3.152600

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.339981

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.013462

1-sigma variation

Unit

MOID

Value

0.004487

1-sigma variation

Unit

Orbit Period

Value

974.5291

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.77614E-19	-9.62710E-18	1.96179E-17	-5.75189E-16	1.41050E-16	-1.10268E-15
e	-9.62710E-18	3.36702E-16	7.43445E-15	-4.10641E-14	7.00856E-14	2.20663E-14
i	1.96179E-17	7.43445E-15	9.00390E-12	3.12575E-12	-3.00320E-12	2.47464E-13
Ω	-5.75189E-16	-4.10641E-14	3.12575E-12	1.16641E-10	-1.13494E-10	-1.25228E-12
ω	1.41050E-16	7.00856E-14	-3.00320E-12	-1.13494E-10	1.19645E-10	-1.09964E-13
M	-1.10268E-15	2.20663E-14	2.47464E-13	-1.25228E-12	-1.09964E-13	3.48311E-12

Date of computation: 2026-09-16 13:00 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

5.370

Unit

Source

[5]

Quality

Value

Unit

Source

[5]

Amplitude

Value

0.18

Unit

mag

Source

[5]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

Unit

Source

[-]

Spinvector B

Value

Unit

Source

[-]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Sq/Sr

Unit

Source

[1]

[2]

Taxonomy (all)

Value

Sq/Sr

Unit

Source

[3]

[4]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

15.818

15.46

Unit

mag

Source

[6]

[2]

Slope Parameter (G)

Value

0.15**

Unit

Source

[6]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.08

0.076

Unit

Source

[8]

[7]

Diameter

Value

3484

Unit

Source

[7]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

0.3097

0.6121

0.318

Unit

g-r

g-i

r-i

Source

[1]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Visual S

Radar R

Unit

Source

[9]

[10]

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Sources

No.	Name	Additional
[1]	EARN	1.) A. V. Sergeyev, B. Carry et al A&A, 658 (2022) A109
[2]	EARN	1.) Tubiana, C. et al. (2015) Astron. Astrophys. 584, A97. (2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites) (10 NEOs)
[3]	EARN	Earth Asteroids Research Node: https://earn.dlr.de
[4]	EARN	1.) Tubiana, C. et al. (2015) Astron. Astrophys. 584, A97. (2P/Encke, the Taurid complex NEOs and the Maribo and Sutter's Mill meteorites) (10 NEOs) 2.) 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)
[5]	EARN	1.) Warner, B.D. (2015) MPB 42, 41-53. (NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT CS3-PALMER DIVIDE STATION: 2014 JUNE-OCTOBER) (45 NEAs) 2.) Warner, B.D. (2015) MPB 42, 115-127. (NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT CS3-PALMER DIVIDE STATION: 2014 OCTOBER-DECEMBER)(43NEAs)
[6]	ESA Aegis	ESA orbit determination and impact monitoring system
[7]	EARN	1.) Mainzer, A. et al. (2011) ApJ 743, 156. (NEOWISE Observations of Near-Earth Objects: Preliminary Results) (albedo and diameters of 428 NEOs)
[8]	EARN	1.) Nugent, C.R. et al. (2016) Astron. J. 152_63 (12pp) (NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos) (207 NEOs) 2.) Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; et al. (2011) Astrophys. J. 741, A90. See also Grav 2012b and Masiero 2012. 3.) Usui, F. et al. (2011) Pub. Astron. Soc. Japan 63, 1117-1138. (Asteroid Catalog Using AKARI: AKARI/IRC Mid-Infrared Asteroid Survey)
[9]	EARN	1.) Binzel, R.P. et al. (2006) LPSC 37, 1491. (The MIT-Hawaii-IRTF joint campaign for NEO spectral reconnaissance.) 2.) Binzel, R.P. et al. href="http://smass.mit.edu/minus.html"> Webpage
[10]	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

10213

Unit

Source

[1]

Unobserved

Value

Unit

Source

[1]

Normalized RMS of residuals

Value

0.415108

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1998-09-29.37562

Unit

Source

[2]

Last Observation

Value

2026-09-15.317684

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

1517 (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

2014-11-21

Unit

Source

[3]

Last Observation

Value

2022-11-18

Unit

Source

[3]

Delay (Discarded)

Value

3 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[-]

Total Radar Observations (Discarded)

Value

3 (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

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Final Date: *

Normalised Only accepted

Max residual (arcsec):

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Plot

Computation parameters

As seen from:

Initial Date: *

Final Date: *

Output option:

One line per time step

Time step:*

* - these fields are required

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 85713 1998SS49 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	2014-11-18 09:37	< 1 s	0.1898151	0.1898151	0.0000000
EARTH	2022-11-21 17:10	< 1 s	0.1413739	0.1413738	0.0000000
EARTH	2030-11-22 20:10	< 1 s	0.1253785	0.1253783	0.0000000
EARTH	2038-11-21 18:04	< 1 s	0.1379070	0.1379069	0.0000001
EARTH	2046-11-21 08:59	< 1 s	0.1547017	0.1547015	0.0000001
EARTH	2054-11-20 15:10	< 1 s	0.1675014	0.1675012	0.0000001

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
41.70966205	116.93340611	0.00448700	MINIMUM
318.14994788	321.55863167	0.08128116	MINIMUM
359.35731790	37.67505713	0.32951317	SADDLE
0.74925350	220.60956930	1.70071633	SADDLE
179.97822814	220.10030379	2.16455105	SADDLE
180.36665367	40.28124347	4.12737151	MAXIMUM

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MOID Plots

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