SpaceAtlas Space Object Data
NASA JPL SBDB · 21277

21277

21277 is an Amor-type near-Earth asteroid that approaches Earth from beyond our orbit without crossing it, orbiting the Sun at 2.378 AU once every 3.67 yr.

Amor Observations: 1,023
Orbital Period · P
3.67 yr
v(q)
34.4 km/s
v(Q)
10.8 km/s
Diameter · ≈
2.06 km
TJ
3.27
Eccentricity · e
0.5203

Orbit and dynamics

The path is an ellipse reaching 1.141 AU from the Sun at perihelion and 3.615 AU at aphelion, a radial span of 2.474 AU.

Applying Kepler's third law to a = 2.378 AU gives an orbital period of 3.67 yr, or about 1,339 days.

The high eccentricity (0.52) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 20.95° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 34.4 km/s at perihelion and falls to 10.8 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 = 16.18 and an assumed geometric albedo of 0.14, the diameter works out to roughly 2.06 km.

Observation record and orbit quality

The current orbit solution is based on 1,023 observations and has a weighted RMS residual of 0.4954 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
2.378 AU
Eccentricity
0.5203
Perihelion
1.141 AU
Aphelion
3.615273 AU
Inclination
20.95°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
8.06°

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
16.18

Orbit Quality

RMS
0.49544
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.

Keep exploring

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