SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 US2

2021 US2

2021 US2 is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.974 AU and a period of 0.96 yr.

Aten Observations: 138
Orbital Period · P
0.96 yr
v(q)
32.3 km/s
v(Q)
28.2 km/s
Diameter · ≈
0.06 km
TJ
6.02
Eccentricity · e
0.0683

Orbit and dynamics

Between its closest point (0.908 AU) and its farthest (1.041 AU), the heliocentric distance changes by 0.133 AU over every revolution.

One full revolution takes 0.96 yr (351 days), computed from the semi-major axis of 0.974 AU.

With e = 0.068, the orbit is close to circular.

A steep inclination of 38.37° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 32.3 km/s at perihelion and falls to 28.2 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 = 23.7 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.06 km.

Observation record and orbit quality

Astrometry from 138 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4765 arcseconds.

Condition code U = 7 signals a poorly constrained orbit, so its future path should be treated as provisional.

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
0.9742 AU
Eccentricity
0.0683
Perihelion
0.908 AU
Aphelion
1.040738 AU
Inclination
38.37°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
134.77°

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
2044-Nov-05 22:04 0.265425 AU
39707068 km
23.28 km/s
2045-Nov-02 13:32 0.128752 AU
19261036 km
20.39 km/s
2046-Oct-30 01:45 0.041123 AU
6151986 km
19.25 km/s
2047-Oct-26 04:53 0.073964 AU
11064921 km
20.18 km/s
2048-Oct-20 17:17 0.151857 AU
22717489 km
22.99 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
23.7

Orbit Quality

RMS
0.47646
Condition
7
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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