SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 AR

2021 AR

2021 AR is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.954 AU and a period of 0.93 yr.

Aten Observations: 29
Orbital Period · P
0.93 yr
v(q)
48.9 km/s
v(Q)
19 km/s
Diameter · ≈
0.06 km
TJ
6.18
Eccentricity · e
0.4387

Orbit and dynamics

The path is an ellipse reaching 0.535 AU from the Sun at perihelion and 1.372 AU at aphelion, a radial span of 0.837 AU.

Applying Kepler's third law to a = 0.954 AU gives an orbital period of 0.93 yr, or about 340 days.

The high eccentricity (0.439) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 20.11° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 48.9 km/s at perihelion and falls to 19 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 = 23.95 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.06 km.

Observation record and orbit quality

The current orbit solution is based on 29 observations and has a weighted RMS residual of 0.3661 arcseconds.

Condition code U = 8 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
0.9539 AU
Eccentricity
0.4387
Perihelion
0.535 AU
Aphelion
1.372376 AU
Inclination
20.11°
Orbital Period
— yr
Epoch
2459218.5
Mean Anomaly
84.03°

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
2034-Jan-01 06:07 0.097800 AU
14630629 km
23.18 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
23.95

Orbit Quality

RMS
0.36614
Condition
8
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.

Keep exploring

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