SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 AJ3

2018 AJ3

2018 AJ3 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.147 AU it takes 1.23 yr to circle the Sun.

Apollo Observations: 49
Orbital Period · P
1.23 yr
v(q)
31.7 km/s
v(Q)
24.4 km/s
Diameter · ≈
0.01 km
TJ
5.47
Eccentricity · e
0.1293

Orbit and dynamics

The path is an ellipse reaching 0.999 AU from the Sun at perihelion and 1.295 AU at aphelion, a radial span of 0.296 AU.

Applying Kepler's third law to a = 1.147 AU gives an orbital period of 1.23 yr, or about 449 days.

An eccentricity of 0.129 makes the orbit moderately elongated.

Its inclination of 4.83° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 31.7 km/s at perihelion and falls to 24.4 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 = 27.7 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.01 km.

Observation record and orbit quality

The current orbit solution is based on 49 observations and has a weighted RMS residual of 0.4296 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
1.147 AU
Eccentricity
0.1293
Perihelion
0.999 AU
Aphelion
1.295307 AU
Inclination
4.83°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
316.56°

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
2028-Aug-04 06:20 0.240763 AU
36017594 km
4.72 km/s
2029-Feb-06 02:08 0.368302 AU
55097268 km
13.73 km/s
2039-Jun-18 13:36 0.279165 AU
41762470 km
5.30 km/s
2044-Sep-11 01:45 0.181555 AU
27160262 km
3.07 km/s
2045-Jan-24 11:15 0.163493 AU
24458168 km
7.55 km/s
2049-Nov-11 00:27 0.336048 AU
50272024 km
11.75 km/s
2050-May-01 16:59 0.242137 AU
36223214 km
4.05 km/s
2055-Jul-17 07:16 0.266509 AU
39869248 km
5.17 km/s
2061-Jan-02 14:46 0.013797 AU
2063972 km
2.94 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
27.7

Orbit Quality

RMS
0.42957
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.

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