SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 WC

2021 WC

2021 WC belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.683 AU it takes 2.18 yr to circle the Sun.

Apollo Observations: 76
Orbital Period · P
2.18 yr
v(q)
35 km/s
v(Q)
15 km/s
Diameter · ≈
0.05 km
TJ
4.12
Eccentricity · e
0.399

Orbit and dynamics

Between its closest point (1.011 AU) and its farthest (2.355 AU), the heliocentric distance changes by 1.344 AU over every revolution.

One full revolution takes 2.18 yr (797 days), computed from the semi-major axis of 1.683 AU.

An eccentricity of 0.399 makes the orbit moderately elongated.

The orbital plane is tilted 8.91° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 35 km/s at perihelion and falls to 15 km/s at aphelion.

Size and surface

No direct size measurement is available; from an absolute magnitude of H = 24.11 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.05 km.

Observation record and orbit quality

Astrometry from 76 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4643 arcseconds.

Condition code U = 6 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
1.683 AU
Eccentricity
0.399
Perihelion
1.011 AU
Aphelion
2.354517 AU
Inclination
8.91°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
30.96°

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
2056-Oct-06 21:08 0.276468 AU
41358977 km
13.80 km/s
2070-Jan-02 00:58 0.339951 AU
50855983 km
16.42 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
24.11

Orbit Quality

RMS
0.46431
Condition
6
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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