Asteroids

12538 1998OH help

Last update: 2025-08-16 12:45 UTC

Orbital Properties

Epoch

61000.0

MJD

Orbit type

Apollo

Perihelion (q)

0.916

Aphelion (Q)

2.167

Eccentricity (e)

0.406

Inclination (i)

24.5

deg

Orbit period (P)

699.1

Earth MOID

0.03022

U parameter

0.0

Next Earth close approach

Date

2042-05-03

Nominal distance (from Earth center)

0.02921

4369549

Maximum Brightness

17.2

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

15.9

mag

Diameter

1663

Taxonomic type

Rotation period (T)

2.585

Discovery Information

Discovery Date

1998-07-19

Observatory

Haleakala-NEAT/GEODSS

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

1.541572

1-sigma variation

2.905E-9

Unit

Eccentricity (e)

Value

0.405902

1-sigma variation

1.577E-8

Unit

Inclination (i)

Value

24.5356

1-sigma variation

3.200E-6

Unit

Long. of Ascending Node (Ω)

Value

220.6879

1-sigma variation

6.041E-6

Unit

Arg. of Perihelion (ω)

Value

321.7891

1-sigma variation

6.634E-6

Unit

Mean Anomaly (M)

Value

163.00614

1-sigma variation

3.918E-6

Unit

Perihelion distance

Value

0.915846

1-sigma variation

Unit

Aphelion distance

Value

2.167299

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.032862

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.898341

1-sigma variation

Unit

MOID

Value

0.030225

1-sigma variation

Unit

Orbit Period

Value

699.1081

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	8.43652E-18	-4.69472E-19	1.32201E-16	5.01933E-16	-3.31256E-15	-7.88327E-15
e	-4.69472E-19	2.48690E-16	-3.97767E-15	7.87239E-15	-6.30681E-16	-1.01067E-14
i	1.32201E-16	-3.97767E-15	1.02395E-11	7.18903E-12	-7.86560E-12	9.28577E-13
Ω	5.01933E-16	7.87239E-15	7.18903E-12	3.64935E-11	-3.29019E-11	1.57548E-13
ω	-3.31256E-15	-6.30681E-16	-7.86560E-12	-3.29019E-11	4.40162E-11	-6.45520E-12
M	-7.88327E-15	-1.01067E-14	9.28577E-13	1.57548E-13	-6.45520E-12	1.53502E-11

Date of computation: 2025-08-16 12:45 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

2.585

5.833

2.580

Unit

Source

[1]

[4]

[2]

Quality

Value

Unit

Source

[4]

Amplitude

Value

0.22

0.12

0.23

Unit

mag

Source

[2]

[4]

[1]

Rotation Direction

Value

Unit

Source

[-]

Spinvector L

Value

198

Unit

Source

[1]

Spinvector B

Value

Unit

Source

[1]

Taxonomy
Taxonomy (all)

Taxonomy

Value

Unit

Source

Taxonomy

Value

Unit

Source

[3]

Taxonomy (all)

Value

Unit

Source

[3]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

15.866

Unit

mag

Source

[5]

Slope Parameter (G)

Value

0.15**

Unit

mag

Source

[5]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.232

Unit

Source

[6]

Diameter

Value

1663

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

[3]

Download this part as:

Sources

No.	Name	Additional
[1]	EARN	1.) Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS): Paper 4. Skiff, Brian A et al.
[2]	EARN	1.) Near-Earth Asteroid Lightcurve Analysis at the Center for Solar System Studies: 2019 March-July, B.D. Warner
[3]	EARN	1.) Binzel, R.P. et al. (2004) Icarus 170, 259-294. (Observed spectral properties of near-Earth objects: results for population distribution, source regions, and space weathering processes.)
[4]	EARN	1.) Warner, B.D. (2015) MPB 42, 115-127. (NEAR-EARTH ASTEROID LIGHTCURVE ANALYSIS AT CS3-PALMER DIVIDE STATION: 2014 OCTOBER-DECEMBER)(43NEAs)
[5]	ESA Aegis	ESA orbit determination and impact monitoring system
[6]	EARN	1.) Mainzer, A. et al. (2011) ApJ 743, 156. (NEOWISE Observations of Near-Earth Objects: Preliminary Results) (albedo and diameters of 428 NEOs) 2.) Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; et al. (2011) Astrophys. J. 741, A90. See also Grav 2012b and Masiero 2012.

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

12363

Unit

Source

[1]

Unobserved

Value

Unit

Source

[1]

Normalized RMS of residuals

Value

0.303475

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1991-10-10.31944

Unit

Source

[2]

Last Observation

Value

2025-08-15.509195

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

11286 (34)

Unit

Source

[1]

Radar Summary

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

Radar

Value

Unit

Source

First Observation

Value

2019-05-14

Unit

Source

[3]

Last Observation

Value

2019-05-14

Unit

Source

[3]

Delay (Discarded)

Value

0 (0)

Unit

Source

[-]

Doppler (Discarded)

Value

1 (0)

Unit

Source

[1]

Total Radar Observations (Discarded)

Value

1 (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

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 12538 1998OH 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	1975-05-04 23:14	< 1 min	0.0372120	0.0372108	0.0000004
EARTH	1998-04-20 10:53	< 1 min	0.1438097	0.1438086	0.0000004
EARTH	2019-05-16 09:48	< 1 s	0.1868278	0.1868277	0.0000001
EARTH	2042-05-03 07:21	< 1 min	0.0292086	0.0292084	0.0000001
EARTH	2065-04-22 23:35	< 1 min	0.1158662	0.1158555	0.0000036
EARTH	2109-05-08 12:46	< 1 min	0.0701060	0.0700928	0.0000044

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
26.54922625	120.03542096	0.03022497	MINIMUM
171.13243875	258.57059484	1.23276631	SADDLE
356.15828558	256.85952536	1.90115720	SADDLE
184.43322602	87.03914246	3.14509069	MAXIMUM

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MOID Plots

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