SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 CD8

2021 CD8

2021 CD8 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.155 AU it takes 1.24 yr to circle the Sun.

Apollo Observations: 48
Orbital Period · P
1.24 yr
v(q)
32.3 km/s
v(Q)
23.8 km/s
Diameter · ≈
0.01 km
TJ
5.44
Eccentricity · e
0.1519

Orbit and dynamics

Between its closest point (0.979 AU) and its farthest (1.33 AU), the heliocentric distance changes by 0.351 AU over every revolution.

One full revolution takes 1.24 yr (453 days), computed from the semi-major axis of 1.155 AU.

An eccentricity of 0.152 makes the orbit moderately elongated.

Its inclination of 0.66° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 32.3 km/s at perihelion and falls to 23.8 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 = 28.55 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.01 km.

Observation record and orbit quality

Astrometry from 48 individual observations underpins this orbit; the fit leaves an RMS residual of 0.5544 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
1.155 AU
Eccentricity
0.1519
Perihelion
0.979 AU
Aphelion
1.330445 AU
Inclination
0.66°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
125.68°

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
2030-Nov-13 09:20 0.346049 AU
51768246 km
13.20 km/s
2031-May-27 10:07 0.264436 AU
39559050 km
4.59 km/s
2036-Jun-26 10:40 0.306288 AU
45819979 km
5.40 km/s
2041-Jul-24 23:44 0.309168 AU
46250841 km
5.46 km/s
2046-Aug-24 03:16 0.272236 AU
40726000 km
4.80 km/s
2047-Mar-15 01:02 0.374842 AU
56075582 km
14.27 km/s
2051-Oct-02 03:44 0.187938 AU
28115164 km
3.05 km/s
2052-Feb-29 12:56 0.142745 AU
21354304 km
7.36 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
28.55

Orbit Quality

RMS
0.55443
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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