SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 PH2

2021 PH2

2021 PH2 is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.873 AU and a period of 0.82 yr.

Aten Observations: 135
Orbital Period · P
0.82 yr
v(q)
63.9 km/s
v(Q)
15.9 km/s
Diameter · ≈
0.17 km
TJ
6.61
Eccentricity · e
0.6006

Orbit and dynamics

The path is an ellipse reaching 0.348 AU from the Sun at perihelion and 1.397 AU at aphelion, a radial span of 1.049 AU.

Applying Kepler's third law to a = 0.873 AU gives an orbital period of 0.82 yr, or about 298 days.

The high eccentricity (0.601) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 10.07° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 63.9 km/s at perihelion and falls to 15.9 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 = 21.56 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.17 km.

Observation record and orbit quality

The current orbit solution is based on 135 observations and has a weighted RMS residual of 0.4063 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
0.8726 AU
Eccentricity
0.6006
Perihelion
0.348 AU
Aphelion
1.396684 AU
Inclination
10.07°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
55.95°

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-Aug-03 03:49 0.172689 AU
25833929 km
14.13 km/s
2040-Oct-26 23:58 0.170773 AU
25547319 km
17.35 km/s
2043-Aug-02 15:53 0.038529 AU
5763904 km
19.14 km/s
2052-Aug-01 06:35 0.134837 AU
20171282 km
14.82 km/s
2062-Oct-28 01:10 0.195412 AU
29233259 km
15.03 km/s
2065-Aug-04 21:26 0.124318 AU
18597730 km
21.86 km/s
2071-Oct-25 12:25 0.190433 AU
28488397 km
20.32 km/s
2074-Aug-01 04:45 0.055674 AU
8328748 km
16.75 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
21.56

Orbit Quality

RMS
0.40635
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.

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