Asteroids

4544 Xanthus help

Last update: 2026-09-04 13:22 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.781

Aphelion (Q)

1.303

Eccentricity (e)

0.250

Inclination (i)

14.1

deg

Orbit period (P)

388.5

Earth MOID

0.17374

U parameter

0.0

Next Earth close approach

Date

2038-05-22

Nominal distance (from Earth center)

0.18669

27927740

Maximum Brightness

16.2

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

17.4

mag

Diameter

760

Taxonomic type

S/Sr

Rotation period (T)

37.65

Discovery Information

Discovery Date

1989-03-31

Observatory

Palomar Mountain

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

1.042051

1-sigma variation

6.543E-10

Unit

Eccentricity (e)

Value

0.250192

1-sigma variation

2.198E-8

Unit

Inclination (i)

Value

14.1431

1-sigma variation

2.573E-6

Unit

Long. of Ascending Node (Ω)

Value

23.9308

1-sigma variation

6.418E-6

Unit

Arg. of Perihelion (ω)

Value

333.8488

1-sigma variation

9.568E-6

Unit

Mean Anomaly (M)

Value

190.44177

1-sigma variation

0.00001

Unit

Perihelion distance

Value

0.781338

1-sigma variation

Unit

Aphelion distance

Value

1.302763

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

-0.199485

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.257116

1-sigma variation

Unit

MOID

Value

0.173744

1-sigma variation

Unit

Orbit Period

Value

388.5363

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	4.28135E-19	4.88191E-18	8.88934E-18	-3.35220E-16	2.75932E-15	-4.63091E-15
e	4.88191E-18	4.82924E-16	9.81997E-15	-1.00888E-14	5.12374E-14	-7.37510E-14
i	8.88934E-18	9.81997E-15	6.62152E-12	-6.60725E-12	5.53416E-12	7.33444E-13
Ω	-3.35220E-16	-1.00888E-14	-6.60725E-12	4.11951E-11	-4.42082E-11	7.40972E-12
ω	2.75932E-15	5.12374E-14	5.53416E-12	-4.42082E-11	9.15388E-11	-7.36707E-11
M	-4.63091E-15	-7.37510E-14	7.33444E-13	7.40972E-12	-7.36707E-11	1.05315E-10

Date of computation: 2026-09-04 13:22 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

37.65

Unit

Source

[3]

Quality

Value

Unit

Source

[3]

Amplitude

Value

0.27

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

S/Sr

Unit

Source

[1]

Taxonomy (all)

Value

Q;Sq,Sr

Unit

Source

[2]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

17.446

Unit

mag

Source

[4]

Slope Parameter (G)

Value

0.15**

Unit

Source

[4]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.37

Unit

Source

[6]

Diameter

Value

760

Unit

Source

[5]

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

[7]

[8]

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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.) Thomas, C.A. et al. (2011) Astron. J. 142, 85. (ExploreNEOs. V. AVERAGE ALBEDO BY TAXONOMIC COMPLEX IN THE NEAR-EARTH ASTEROID POPULATION) (new albedos data for 118 NEOs) 2.) Thomas, C.A. et al. (2014) Icarus 228, 217-246. (Physical characterization of Warm Spitzer-observed near-Earth objects) 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)
[3]	EARN	1.) R. Behrend Courbes des lumiere, Observatoire de Geneve website
[4]	ESA Aegis	ESA orbit determination and impact monitoring system
[5]	EARN	1.) Calculated by the NEOCC based on the albedo value
[6]	EARN	1.) Thomas, C.A. et al. (2011) Astron. J. 142, 85. (ExploreNEOs. V. AVERAGE ALBEDO BY TAXONOMIC COMPLEX IN THE NEAR-EARTH ASTEROID POPULATION) (new albedos data for 118 NEOs)
[7]	EARN	1.) Benner, L.A.M. et al. (1996) B.A.A.S. 28, 1105. 10.41. (Radar Observations of Near-Earth Asteroids 2062 Aten, 2101 Adonis, 3103 Eger, 4544 Xanthus, and 1992 QN) 2.) Benner, L.A.M. et al. (1997) Icarus 130, 296-312. (Radar Detection of Near-Earth Asteroids 2062 Aten, 2101 Adonis, 3103 Eger, 4544 Xanthus, and 1992 QN) 3.) Ostro, S.J. et al. (1991) Astron. J. 102, 1490-1502. (Asteroid radar astrometry)
[8]	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

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

13548

Unit

Source

[1]

Unobserved

Value

164

Unit

Source

[1]

Normalized RMS of residuals

Value

0.426674

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1989-03-30.35087

Unit

Source

[2]

Last Observation

Value

2026-05-03.279478

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

2971 (13)

Unit

Source

[1]

Radar Summary

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

Radar

Value

Unit

Source

First Observation

Value

1990-11-19

Unit

Source

[3]

Last Observation

Value

1990-11-19

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

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Final Date: *

Normalised Only accepted

Max residual (arcsec):

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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 4544 Xanthus 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	1973-10-26 04:57	< 1 min	0.1878273	0.1878271	0.0000001
EARTH	1988-05-19 22:48	< 1 min	0.1795384	0.1795383	0.0000000
EARTH	1990-11-18 00:04	< 1 min	0.1733300	0.1733299	0.0000000
EARTH	2005-05-10 05:46	< 1 min	0.1937738	0.1937736	0.0000001
EARTH	2023-10-21 21:19	< 1 min	0.1955524	0.1955523	0.0000000
EARTH	2038-05-22 07:50	< 1 s	0.1866854	0.1866853	0.0000000
EARTH	2040-11-12 00:43	< 1 min	0.1738511	0.1738511	0.0000000
EARTH	2055-05-13 21:53	< 1 min	0.1877605	0.1877603	0.0000001
EARTH	2057-12-01 06:03	< 1 min	0.1921702	0.1921700	0.0000001
EARTH	2090-11-05 07:27	< 1 min	0.1784522	0.1784521	0.0000001
EARTH	2105-05-18 04:51	< 1 min	0.1823415	0.1823414	0.0000001
EARTH	2107-11-27 18:24	< 1 min	0.1824696	0.1824693	0.0000001

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
43.91002800	308.50776986	0.17374438	MINIMUM
254.34153492	132.75788634	0.17909797	MINIMUM
326.32476716	211.92116386	0.28258534	SADDLE
155.23415011	54.34380776	0.34904741	SADDLE
352.17274541	65.22321774	1.77209914	SADDLE
179.64199648	253.08304295	2.30419417	MAXIMUM

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MOID Plots

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