SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 CJ2

2021 CJ2

2021 CJ2 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.381 AU it takes 1.62 yr to circle the Sun.

Apollo Observations: 37
Orbital Period · P
1.62 yr
v(q)
64.5 km/s
v(Q)
10 km/s
Diameter · ≈
0.17 km
TJ
4.47
Eccentricity · e
0.7328

Orbit and dynamics

Between its closest point (0.369 AU) and its farthest (2.393 AU), the heliocentric distance changes by 2.024 AU over every revolution.

One full revolution takes 1.62 yr (593 days), computed from the semi-major axis of 1.381 AU.

The high eccentricity (0.733) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

Its inclination of 3.94° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 64.5 km/s at perihelion and falls to 10 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 = 21.58 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.17 km.

Observation record and orbit quality

Astrometry from 37 individual observations underpins this orbit; the fit leaves an RMS residual of 0.6455 arcseconds.

Condition code U = 2 means the orbit is very well determined, leaving only a small uncertainty in the future ephemeris.

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
1.381 AU
Eccentricity
0.7328
Perihelion
0.369 AU
Aphelion
2.392997 AU
Inclination
3.94°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
151.24°

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
2029-Feb-11 07:03 0.324028 AU
48473845 km
34.67 km/s
2030-Jun-09 20:35 0.489926 AU
73291905 km
13.00 km/s
2030-Jul-20 19:59 0.482657 AU
72204402 km
16.58 km/s
2033-Dec-12 08:51 0.463967 AU
69408549 km
16.22 km/s
2034-Jan-20 06:20 0.465676 AU
69664143 km
13.40 km/s
2035-May-19 00:25 0.282218 AU
42219230 km
33.09 km/s
2042-Feb-09 17:23 0.282500 AU
42261347 km
33.31 km/s
2043-Jun-12 18:38 0.446237 AU
66756135 km
13.19 km/s
2046-Dec-05 13:37 0.490290 AU
73346316 km
18.74 km/s
2048-May-16 10:35 0.323850 AU
48447278 km
34.42 km/s
2055-Feb-07 18:07 0.232866 AU
34836332 km
31.74 km/s
2056-Jun-13 07:48 0.399990 AU
59837586 km
13.87 km/s
2061-May-14 22:33 0.362528 AU
54233410 km
35.67 km/s
2068-Feb-06 04:24 0.190579 AU
28510218 km
30.41 km/s
2069-Jun-13 08:49 0.353930 AU
52947138 km
14.89 km/s
2074-May-13 00:41 0.408880 AU
61167564 km
37.16 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
21.58

Orbit Quality

RMS
0.64547
Condition
2
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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