SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 RA1

2018 RA1

2018 RA1 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.142 AU it takes 1.22 yr to circle the Sun.

Apollo Observations: 56
Orbital Period · P
1.22 yr
v(q)
39 km/s
v(Q)
19.9 km/s
Diameter · ≈
0.02 km
TJ
5.43
Eccentricity · e
0.3238

Orbit and dynamics

The path is an ellipse reaching 0.772 AU from the Sun at perihelion and 1.512 AU at aphelion, a radial span of 0.74 AU.

Applying Kepler's third law to a = 1.142 AU gives an orbital period of 1.22 yr, or about 446 days.

An eccentricity of 0.324 makes the orbit moderately elongated.

The orbital plane is tilted 8.63° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 39 km/s at perihelion and falls to 19.9 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 = 26.4 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.02 km.

Observation record and orbit quality

The current orbit solution is based on 56 observations and has a weighted RMS residual of 0.2398 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
1.142 AU
Eccentricity
0.3238
Perihelion
0.772 AU
Aphelion
1.51178 AU
Inclination
8.63°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
72.67°

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
2029-Sep-04 04:23 0.076768 AU
11484300 km
13.33 km/s
2031-Mar-23 20:23 0.408620 AU
61128742 km
23.06 km/s
2035-Jul-26 20:40 0.381921 AU
57134508 km
7.70 km/s
2036-Mar-26 16:38 0.277847 AU
41565315 km
6.62 km/s
2040-Aug-26 16:30 0.225925 AU
33797907 km
18.10 km/s
2042-Mar-15 18:23 0.220409 AU
32972666 km
18.10 km/s
2047-Apr-17 23:18 0.377758 AU
56511867 km
7.95 km/s
2051-Aug-19 23:09 0.373333 AU
55849778 km
22.64 km/s
2053-Mar-07 23:30 0.049400 AU
7390166 km
13.48 km/s
2058-May-01 11:08 0.442427 AU
66186130 km
8.66 km/s
2064-Mar-01 12:23 0.014095 AU
2108520 km
10.07 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
26.4

Orbit Quality

RMS
0.23983
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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