SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 OS

2021 OS

2021 OS is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.811 AU and a period of 0.73 yr.

Aten Observations: 197
Orbital Period · P
0.73 yr
v(q)
52.6 km/s
v(Q)
20.8 km/s
Diameter · ≈
0.14 km
TJ
7.11
Eccentricity · e
0.4326

Orbit and dynamics

The path is an ellipse reaching 0.46 AU from the Sun at perihelion and 1.161 AU at aphelion, a radial span of 0.701 AU.

Applying Kepler's third law to a = 0.811 AU gives an orbital period of 0.73 yr, or about 267 days.

The high eccentricity (0.433) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 15.45° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 52.6 km/s at perihelion and falls to 20.8 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 = 22.04 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.14 km.

Observation record and orbit quality

The current orbit solution is based on 197 observations and has a weighted RMS residual of 0.3577 arcseconds.

Condition code U = 0 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
0.8107 AU
Eccentricity
0.4326
Perihelion
0.46 AU
Aphelion
1.161409 AU
Inclination
15.45°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
1.03°

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

No close approaches to Earth are currently on record for this object.

Physical Parameters

Diameter
— km
Albedo
—
Density
— g/cm³
Rotation Period
— h
Absolute Magnitude
22.04

Orbit Quality

RMS
0.35772
Condition
0
Orbit ID
—
Data source: NASA JPL Small-Body Database . 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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