Asteroids

162173 Ryugu help

Last update: 2026-06-04 23:11 UTC

Orbital Properties

Epoch

61200.0

MJD

Orbit type

Apollo

Perihelion (q)

0.963

Aphelion (Q)

1.418

Eccentricity (e)

0.191

Inclination (i)

5.9

deg

Orbit period (P)

474.7

Earth MOID

0.00054

U parameter

0.0

Next Earth close approach

Date

2033-12-21

Nominal distance (from Earth center)

0.04745

7097724

Maximum Brightness

16.7

mag

Risk

Object is not in risk list

Physical Properties

Absolute Magnitude (H)

19.5

mag

Diameter

960

Taxonomic type

Rotation period (T)

Discovery Information

Discovery Date

1999-05-10

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

1.190919

1-sigma variation

9.883E-10

Unit

Eccentricity (e)

Value

0.191073

1-sigma variation

8.548E-9

Unit

Inclination (i)

Value

5.8664

1-sigma variation

9.035E-7

Unit

Long. of Ascending Node (Ω)

Value

251.2897

1-sigma variation

6.185E-6

Unit

Arg. of Perihelion (ω)

Value

211.6090

1-sigma variation

6.349E-6

Unit

Mean Anomaly (M)

Value

62.34066

1-sigma variation

2.024E-6

Unit

Perihelion distance

Value

0.963367

1-sigma variation

Unit

Aphelion distance

Value

1.418471

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.356485

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.000680

1-sigma variation

Unit

MOID

Value

0.000539

1-sigma variation

Unit

Orbit Period

Value

474.7027

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	9.76726E-19	-3.76990E-18	-1.87225E-16	7.53493E-16	-2.20269E-15	-1.06213E-15
e	-3.76990E-18	7.30605E-17	1.25705E-15	-4.32912E-15	1.75233E-14	1.24997E-15
i	-1.87225E-16	1.25705E-15	8.16388E-13	-4.91774E-13	7.98274E-13	2.38549E-13
Ω	7.53493E-16	-4.32912E-15	-4.91774E-13	3.82556E-11	-3.49162E-11	-4.67701E-12
ω	-2.20269E-15	1.75233E-14	7.98274E-13	-3.49162E-11	4.03053E-11	1.93598E-12
M	-1.06213E-15	1.24997E-15	2.38549E-13	-4.67701E-12	1.93598E-12	4.09708E-12

Date of computation: 2026-06-04 23:11 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

Unit

Source

[-]

Quality

Value

Unit

Source

[-]

Amplitude

Value

Unit

mag

Source

[-]

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

[3]

Absolute Magnitude (H)
Slope Parameter (G)

H / G

Value

Unit

Source

Absolute Magnitude (H)

Value

19.464

Unit

mag

Source

[4]

Slope Parameter (G)

Value

0.15**

Unit

Source

[4]

Albedo
Diameter

Size and albedo

Value

Unit

Source

Albedo

Value

0.029

Unit

Source

[5]

Diameter

Value

960

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

Unit

Source

[-]

Download this part as:

Sources

No.	Name	Additional
[1]	EARN	1.) Michaël Marsset et al 2022 AJ 163 165
[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]	ESA Aegis	ESA orbit determination and impact monitoring system
[5]	EARN	1.) Joseph R. Masiero et al 2021 Planet. Sci. J. 2 162

Observational Information

Arc Length
Unobserved
Normalized RMS of residuals

Arc Information

Value

Unit

Source

Arc Length

Value

14345

Unit

Source

[1]

Unobserved

Value

361

Unit

Source

[1]

Normalized RMS of residuals

Value

0.344303

Unit

Source

[1]

Astrometry Summary

First Observation
Last Observation
Total Optical Observations (Discarded)

Optical

Value

Unit

Source

First Observation

Value

1986-04-14.58606

Unit

Source

[2]

Last Observation

Value

2025-07-23.341273

Unit

Source

[2]

Total Optical Observations (Discarded)

Value

4999 (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

2020-12-12

Unit

Source

[3]

Last Observation

Value

2020-12-18

Unit

Source

[3]

Delay (Discarded)

Value

2 (0)

Unit

Source

[1]

Doppler (Discarded)

Value

0 (0)

Unit

Source

[-]

Total Radar Observations (Discarded)

Value

2 (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: *

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Max residual (arcsec):

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Computation parameters

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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 162173 Ryugu 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	1972-11-20 13:56	< 1 min	0.0826683	0.0826668	0.0000005
EARTH	1985-11-24 21:15	< 1 min	0.0497901	0.0497898	0.0000001
EARTH	2008-02-20 15:56	< 1 s	0.1639306	0.1639303	0.0000001
EARTH	2020-12-29 00:45	< 1 s	0.0605274	0.0605274	0.0000000
EARTH	2033-12-21 05:53	< 1 min	0.0474454	0.0474451	0.0000001
EARTH	2047-02-16 10:36	< 1 s	0.1427837	0.1427836	0.0000000
EARTH	2063-11-16 06:51	< 1 min	0.1413005	0.1412999	0.0000002
EARTH	2076-12-06 05:42	< 1 min	0.0104428	0.0104424	0.0000002
EARTH	2101-12-29 19:17	13.8	0.0585036	0.0584555	0.0000160
EARTH	2105-11-12 02:08	1.3	0.1952545	0.1951996	0.0000183

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
333.92298304	327.61677385	0.00053852	MINIMUM
183.72756391	181.44243574	0.40717857	SADDLE
0.63884062	179.14814241	1.97948503	SADDLE
179.31060011	357.76733661	2.40116847	MAXIMUM

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MOID Plots

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