SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 PJ

2021 PJ

2021 PJ is an Amor-type near-Earth asteroid that approaches Earth from beyond our orbit without crossing it, orbiting the Sun at 1.562 AU once every 1.95 yr.

Amor Observations: 149
Orbital Period · P
1.95 yr
v(q)
34.2 km/s
v(Q)
16.6 km/s
Diameter · ≈
0.07 km
TJ
4.35
Eccentricity · e
0.3461

Orbit and dynamics

The path is an ellipse reaching 1.021 AU from the Sun at perihelion and 2.103 AU at aphelion, a radial span of 1.082 AU.

Applying Kepler's third law to a = 1.562 AU gives an orbital period of 1.95 yr, or about 713 days.

An eccentricity of 0.346 makes the orbit moderately elongated.

The orbital plane is tilted 9.68° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 34.2 km/s at perihelion and falls to 16.6 km/s at aphelion.

Its perihelion lies just outside Earth's orbit, which is why it is classed as Earth-approaching rather than Earth-crossing.

Size and surface

No direct size measurement is available; from an absolute magnitude of H = 23.44 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.07 km.

Observation record and orbit quality

The current orbit solution is based on 149 observations and has a weighted RMS residual of 0.4304 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
1.562 AU
Eccentricity
0.3461
Perihelion
1.021 AU
Aphelion
2.102608 AU
Inclination
9.68°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
170.59°

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
2064-Jul-02 17:23 0.182075 AU
27237967 km
11.11 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
23.44

Orbit Quality

RMS
0.43039
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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