Asteroids

450894 2008BT18 help

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

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.900

Aphelion (Q)

3.539

Eccentricity (e)

0.595

Inclination (i)

8.1

deg

Orbit period (P)

1207.6

Earth MOID

0.01276

U parameter

0.0

Next Earth close approach

Date

2051-07-31

Nominal distance (from Earth center)

0.18701

27975849

Maximum Brightness

17.3

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

18.2

mag

Diameter

600 - 1400*

Taxonomic type

Rotation period (T)

2.570

Discovery Information

Discovery Date

2008-01-31

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

2.219304

1-sigma variation

2.420E-9

Unit

Eccentricity (e)

Value

0.594536

1-sigma variation

1.327E-8

Unit

Inclination (i)

Value

8.1457

1-sigma variation

4.623E-6

Unit

Long. of Ascending Node (Ω)

Value

107.5245

1-sigma variation

1.554E-5

Unit

Arg. of Perihelion (ω)

Value

139.3874

1-sigma variation

1.617E-5

Unit

Mean Anomaly (M)

Value

157.46920

1-sigma variation

3.521E-6

Unit

Perihelion distance

Value

0.899847

1-sigma variation

Unit

Aphelion distance

Value

3.538760

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

1.632088

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

-0.028254

1-sigma variation

Unit

MOID

Value

0.012762

1-sigma variation

Unit

Orbit Period

Value

1207.6012

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	5.85813E-18	-1.64799E-17	3.51685E-15	4.56079E-15	3.07328E-15	-8.43987E-15
e	-1.64799E-17	1.76175E-16	-1.20387E-14	-7.38986E-14	3.37685E-14	2.77701E-14
i	3.51685E-15	-1.20387E-14	2.13707E-11	2.40516E-11	-1.90918E-11	-4.29143E-12
Ω	4.56079E-15	-7.38986E-14	2.40516E-11	2.41430E-10	-2.40007E-10	-5.17563E-12
ω	3.07328E-15	3.37685E-14	-1.90918E-11	-2.40007E-10	2.61418E-10	-7.20720E-12
M	-8.43987E-15	2.77701E-14	-4.29143E-12	-5.17563E-12	-7.20720E-12	1.23961E-11

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

2.570

2.726

Unit

Source

[4]

[5]

Quality

Value

2,B

2,B,R

Unit

Source

[5]

[4]

Amplitude

Value

0.045

0.3

Unit

mag

Source

[5]

[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

18.174

Unit

mag

Source

[6]

Slope Parameter (G)

Value

0.15**

Unit

Source

[6]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.05 - 0.25

Unit

Source

[7]

Diameter

Value

600 - 1400*

Unit

Source

[7]

Color Index Information

Color Index Information

Value

Unit

Source

Color Index Information

Value

Unit

mag

Source

[-]

Sightings

Sightings

Value

Unit

Source

Sightings

Value

Radar R

Visual S

Unit

Source

[8]

[1]

Satellites

Satellites

Value

Unit

Source

Satellites

Value

Binary Child 1

Unit

Source

[3]

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Sources

No.	Name	Additional
[1]	EARN	1.) Reddy, V. et al. (2008) DPS 40, 2507. (Compositional Investigation of Binary Potentially-Hazardous Asteroid 2008 BT18: A Basaltic Achondrite)
[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.) Warner, B.D. (2018) MPB 45, 248-256. (Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2018 January-April)(28 NEOs) 2.) Petr Pravec's Ondrejov NEO Photometric Program Webpage "Prepublished Periods" 3.) Betzler, A.S. & Novaes, A.B. (2009) MPB 36, 94-96. (OBSERVATIONS OF V-TYPE BINARY NEAR-EARTH ASTEROIDS 2006 VV2 AND 2008 BT18)
[5]	EARN	1.) Betzler, A.S. & Novaes, A.B. (2009) MPB 36, 94-96. (OBSERVATIONS OF V-TYPE BINARY NEAR-EARTH ASTEROIDS 2006 VV2 AND 2008 BT18)
[6]	ESA Aegis	ESA orbit determination and impact monitoring system
[7]	Estimation	Estimated from absolute magnitude
[8]	EARN	1.) href="http://echo.jpl.nasa.gov/asteroids/index.html">JPL's NEO Radar Detection Program Webpage 2.) Benner, L.A.M. et al. (2008) CBET HREF="http://www.cbat.eps.harvard.edu/iau/cbet/001400/CBET001450.txt"> 1450. (2008 BT_18) (Radar detection of binary system)

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

25826

Unit

Source

[1]

Unobserved

Value

353

Unit

Source

[1]

Normalized RMS of residuals

Value

0.559527

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1955-03-14.22639

Unit

Source

[2]

Last Observation

Value

2025-11-26.730127

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

453 (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

2008-07-06

Unit

Source

[3]

Last Observation

Value

2008-07-07

Unit

Source

[3]

Delay (Discarded)

Value

2 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

1 (0)

Unit

Source

[1]

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: *

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Max residual (arcsec):

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Computation parameters

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Final Date: *

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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 450894 2008BT18 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	1955-06-09 07:52	1.3	0.1270381	0.1270343	0.0000013
EARTH	1965-04-11 07:12	< 1 min	0.1430233	0.1430217	0.0000006
EARTH	2008-07-14 14:54	< 1 s	0.0150803	0.0150802	0.0000000
52 Europa	2009-04-30 06:51	< 1 min	0.0191849	0.0191844	0.0000002
EARTH	2018-04-15 13:19	< 1 min	0.1411213	0.1411210	0.0000001
EARTH	2051-07-31 10:15	< 1 min	0.1870070	0.1870059	0.0000004
EARTH	2061-06-17 13:34	< 1 min	0.1192698	0.1192693	0.0000002
1 Ceres	2072-02-22 08:08	< 1 min	0.0182183	0.0182176	0.0000002
EARTH	2094-07-30 11:58	< 1 s	0.1581778	0.1581773	0.0000002
EARTH	2104-06-26 04:32	< 1 min	0.0908121	0.0908120	0.0000000
EARTH	2114-04-08 11:16	< 1 s	0.1728229	0.1728225	0.0000001

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
23.70652704	187.78548853	0.01276209	MINIMUM
339.64967939	102.46453072	0.14041345	MINIMUM
353.34026213	128.79160805	0.14968251	SADDLE
0.44789305	323.05222563	1.88470635	SADDLE
179.91732438	322.91738879	2.55774452	SADDLE
180.39261617	143.16008152	4.54885472	MAXIMUM

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MOID Plots

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