Asteroids

162173 Ryugu help

Last update: 2025-09-10 00:30 UTC

Orbital Properties

Epoch

61000.0

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

0.00083

U parameter

0.0

Next Earth close approach

Date

2033-12-21

Nominal distance (from Earth center)

0.04745

7097719

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

61000.0000

1-sigma variation

Unit

MJD

Semimajor Axis

Value

1.190921

1-sigma variation

9.973E-10

Unit

Eccentricity (e)

Value

0.191063

1-sigma variation

8.582E-9

Unit

Inclination (i)

Value

5.8666

1-sigma variation

9.041E-7

Unit

Long. of Ascending Node (Ω)

Value

251.2915

1-sigma variation

6.188E-6

Unit

Arg. of Perihelion (ω)

Value

211.6168

1-sigma variation

6.361E-6

Unit

Mean Anomaly (M)

Value

270.65938

1-sigma variation

1.931E-6

Unit

Perihelion distance

Value

0.963381

1-sigma variation

Unit

Aphelion distance

Value

1.418462

1-sigma variation

Unit

Asc. Node-Earth Sep.

Value

0.354737

1-sigma variation

Unit

Desc. Node-Earth Sep.

Value

0.001045

1-sigma variation

Unit

MOID

Value

0.000833

1-sigma variation

Unit

Orbit Period

Value

474.7040

1-sigma variation

Unit

U parameter

Value

0.0

1-sigma variation

Unit

Covariance Matrix

	a	e	i	Ω	ω	M
a	9.94532E-19	-3.86157E-18	-1.90770E-16	7.60416E-16	-2.24996E-15	-8.75801E-16
e	-3.86157E-18	7.36499E-17	1.27608E-15	-4.34790E-15	1.77925E-14	5.15179E-16
i	-1.90770E-16	1.27608E-15	8.17449E-13	-4.96449E-13	8.10713E-13	2.02807E-13
Ω	7.60416E-16	-4.34790E-15	-4.96449E-13	3.82928E-11	-3.49576E-11	-4.53787E-12
ω	-2.24996E-15	1.77925E-14	8.10713E-13	-3.49576E-11	4.04607E-11	1.51247E-12
M	-8.75801E-16	5.15179E-16	2.02807E-13	-4.53787E-12	1.51247E-12	3.72750E-12

Date of computation: 2025-09-10 00:30 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

19.465

Unit

mag

Source

[4]

Slope Parameter (G)

Value

0.15**

Unit

mag

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

Unit

Source

[1]

Normalized RMS of residuals

Value

0.34461

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

4986 (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

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 162173 Ryugu 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	1972-11-20 13:56	< 1 min	0.0826682	0.0826667	0.0000005
EARTH	1985-11-24 21:15	< 1 min	0.0497902	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	0.0474453	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	0.1413004	0.1412998	0.0000002
EARTH	2076-12-06 05:42	< 1 min	0.0104429	0.0104424	0.0000002
EARTH	2101-12-29 19:12	13.8	0.0584980	0.0584497	0.0000161
EARTH	2105-11-12 02:07	1.3	0.1952608	0.1952057	0.0000184

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Stationary Points

Ecc. an. ast.	Ecc. an. Earth	Distance in au	Classification
333.99287280	329.83285582	0.00076845	MINIMUM
183.85739813	183.75043307	0.40775336	SADDLE
0.85395861	181.54133562	1.97900449	SADDLE
179.44682408	0.08044210	2.40132019	MAXIMUM

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MOID Plots

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