SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 SY2

2018 SY2

2018 SY2 is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.774 AU and a period of 0.68 yr.

Aten Observations: 35
Orbital Period · P
0.68 yr
v(q)
50.7 km/s
v(Q)
22.6 km/s
Diameter · ≈
0.25 km
TJ
7.36
Eccentricity · e
0.3839

Orbit and dynamics

The path is an ellipse reaching 0.477 AU from the Sun at perihelion and 1.071 AU at aphelion, a radial span of 0.594 AU.

Applying Kepler's third law to a = 0.774 AU gives an orbital period of 0.68 yr, or about 249 days.

An eccentricity of 0.384 makes the orbit moderately elongated.

A steep inclination of 26.77° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 50.7 km/s at perihelion and falls to 22.6 km/s at aphelion.

Because q < 1 AU and Q > 1 AU, this orbit geometrically intersects the region of Earth's orbit.

Size and surface

No direct size measurement is available; from an absolute magnitude of H = 20.8 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.25 km.

Observation record and orbit quality

The current orbit solution is based on 35 observations and has a weighted RMS residual of 0.6226 arcseconds.

Condition code U = 3 indicates a moderately constrained orbit; predictions decades ahead still carry noticeable uncertainty.

About these computed values

Orbital periods, perihelion and aphelion speeds, and diameter estimates on this page are computed by SpaceAtlas from the JPL SBDB orbital elements. They are derived quantities, not values copied from the source catalogue.

Orbital Parameters

Semi-Major Axis
0.7736 AU
Eccentricity
0.3839
Perihelion
0.477 AU
Aphelion
1.070585 AU
Inclination
26.77°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
315.08°

Orbit diagram

The Sun sits at the focus (orange). Earth's orbit is the grey circle at 1 AU. The red dot marks the object's position at the catalog epoch.

3D orbit (interactive)

Drag to rotate; scroll or pinch to zoom. The Sun is at the focus (orange), Earth's orbit is the grey ring at 1 AU, and the red dot marks the object's current position.

Close approaches

Predicted close approaches to Earth, from NASA's Center for Near-Earth Object Studies (CNEOS).

Date (UTC)Miss distanceVelocity
2031-May-23 17:18 0.472521 AU
70688153 km
14.34 km/s
2031-Oct-31 15:45 0.427570 AU
63963533 km
20.95 km/s
2033-Jun-26 12:08 0.292983 AU
43829659 km
14.19 km/s
2033-Nov-22 19:24 0.353731 AU
52917350 km
18.97 km/s
2035-Jul-14 22:50 0.183998 AU
27525705 km
17.00 km/s
2035-Dec-17 19:39 0.373668 AU
55899995 km
19.65 km/s
2037-Jul-28 08:32 0.302861 AU
45307392 km
22.15 km/s
2038-Jan-11 00:21 0.448161 AU
67043882 km
21.46 km/s
2048-Jun-04 15:07 0.421628 AU
63074662 km
14.06 km/s
2048-Nov-06 14:01 0.395052 AU
59098999 km
20.03 km/s
2050-Jul-03 06:46 0.240748 AU
36015370 km
14.73 km/s
2050-Nov-30 17:44 0.350608 AU
52450230 km
18.96 km/s
2052-Jul-18 20:00 0.200452 AU
29987192 km
18.43 km/s
2052-Dec-24 22:02 0.394062 AU
58950875 km
20.17 km/s
2054-Aug-01 15:23 0.362860 AU
54283064 km
24.03 km/s
2055-Jan-18 21:00 0.473934 AU
70899553 km
22.00 km/s
2063-Oct-23 20:46 0.479262 AU
71696590 km
22.57 km/s
2065-Jun-15 19:11 0.366386 AU
54810540 km
13.97 km/s
2065-Nov-13 12:23 0.371620 AU
55593557 km
19.40 km/s
2067-Jul-08 14:02 0.204836 AU
30643027 km
15.49 km/s
2067-Dec-07 19:29 0.355717 AU
53214550 km
19.13 km/s
2069-Jul-22 20:40 0.232748 AU
34818551 km
19.81 km/s
2069-Dec-31 17:52 0.413817 AU
61906213 km
20.67 km/s
2071-Aug-05 06:07 0.415803 AU
62203293 km
25.67 km/s
2072-Jan-25 12:42 0.495246 AU
74087684 km
22.38 km/s

Distances in astronomical units (AU) and kilometres. Source: NASA/JPL CNEOS Close Approach Data API.

Physical Parameters

Diameter
— km
Albedo
—
Density
— g/cm³
Rotation Period
— h
Absolute Magnitude
20.8

Orbit Quality

RMS
0.62257
Condition
3
Orbit ID
—
Data source: NASA JPL Small-Body Database · NASA CNEOS. Orbital periods, perihelion and aphelion speeds, and diameter estimates on this page are computed by SpaceAtlas from the JPL SBDB orbital elements. They are derived quantities, not values copied from the source catalogue.

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