SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 PO

2021 PO

2021 PO belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.813 AU it takes 2.44 yr to circle the Sun.

Apollo Observations: 155
Orbital Period · P
2.44 yr
v(q)
74.1 km/s
v(Q)
6.6 km/s
Diameter · ≈
0.47 km
TJ
3.51
Eccentricity · e
0.8361

Orbit and dynamics

Between its closest point (0.297 AU) and its farthest (3.329 AU), the heliocentric distance changes by 3.032 AU over every revolution.

One full revolution takes 2.44 yr (892 days), computed from the semi-major axis of 1.813 AU.

The high eccentricity (0.836) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 8.97° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 74.1 km/s at perihelion and falls to 6.6 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 = 19.37 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.47 km.

Observation record and orbit quality

Astrometry from 155 individual observations underpins this orbit; the fit leaves an RMS residual of 0.3729 arcseconds.

Condition code U = 1 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
1.813 AU
Eccentricity
0.8361
Perihelion
0.297 AU
Aphelion
3.328849 AU
Inclination
8.97°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
321.73°

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-Apr-05 11:20 0.448463 AU
67089142 km
16.62 km/s
2043-Sep-01 00:29 0.180005 AU
26928335 km
24.17 km/s
2046-May-06 00:08 0.232600 AU
34796520 km
34.00 km/s
2065-Aug-25 04:01 0.063615 AU
9516665 km
28.53 km/s
2068-Apr-28 19:59 0.161222 AU
24118498 km
29.47 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
19.37

Orbit Quality

RMS
0.37287
Condition
1
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

Explore asteroids, comets and near-Earth objects with JPL orbital data.