SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 EP4

2021 EP4

2021 EP4 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.576 AU it takes 1.98 yr to circle the Sun.

Apollo Observations: 67
Orbital Period · P
1.98 yr
v(q)
35.6 km/s
v(Q)
15.8 km/s
Diameter · ≈
0 km
TJ
4.31
Eccentricity · e
0.3842

Orbit and dynamics

Between its closest point (0.971 AU) and its farthest (2.181 AU), the heliocentric distance changes by 1.21 AU over every revolution.

One full revolution takes 1.98 yr (723 days), computed from the semi-major axis of 1.576 AU.

An eccentricity of 0.384 makes the orbit moderately elongated.

The orbital plane is tilted 5° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 35.6 km/s at perihelion and falls to 15.8 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 = 29.26 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0 km.

Observation record and orbit quality

Astrometry from 67 individual observations underpins this orbit; the fit leaves an RMS residual of 0.3879 arcseconds.

Condition code U = 6 indicates a moderately constrained orbit; predictions decades ahead still carry noticeable uncertainty.

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
1.576 AU
Eccentricity
0.3842
Perihelion
0.971 AU
Aphelion
2.181499 AU
Inclination
5.0°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
240.99°

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
2027-Jan-03 20:10 0.206389 AU
30875320 km
12.60 km/s
2028-Dec-25 13:03 0.332734 AU
49776348 km
16.75 km/s
2030-Dec-18 07:43 0.466965 AU
69856911 km
21.00 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
29.26

Orbit Quality

RMS
0.38789
Condition
6
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

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