SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 SL4

2021 SL4

2021 SL4 is an Amor-type near-Earth asteroid that approaches Earth from beyond our orbit without crossing it, orbiting the Sun at 2.835 AU once every 4.77 yr.

Amor Observations: 24
Orbital Period · P
4.77 yr
v(q)
35.8 km/s
v(Q)
8.7 km/s
Diameter · ≈
0.04 km
TJ
3.01
Eccentricity · e
0.6078

Orbit and dynamics

The path is an ellipse reaching 1.112 AU from the Sun at perihelion and 4.558 AU at aphelion, a radial span of 3.446 AU.

Applying Kepler's third law to a = 2.835 AU gives an orbital period of 4.77 yr, or about 1,743 days.

The high eccentricity (0.608) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

Its inclination of 2.85° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 35.8 km/s at perihelion and falls to 8.7 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 = 24.66 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.04 km.

Observation record and orbit quality

The current orbit solution is based on 24 observations and has a weighted RMS residual of 0.5608 arcseconds.

Condition code U = 7 signals a poorly constrained orbit, so its future path should be treated as provisional.

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
2.835 AU
Eccentricity
0.6078
Perihelion
1.112 AU
Aphelion
4.558113 AU
Inclination
2.85°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
353.07°

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
24.66

Orbit Quality

RMS
0.56083
Condition
7
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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