SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 AL18

2018 AL18

2018 AL18 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.285 AU it takes 1.46 yr to circle the Sun.

Apollo Observations: 72
Orbital Period · P
1.46 yr
v(q)
33.4 km/s
v(Q)
20.7 km/s
Diameter · ≈
0.15 km
TJ
4.98
Eccentricity · e
0.234

Orbit and dynamics

Between its closest point (0.984 AU) and its farthest (1.586 AU), the heliocentric distance changes by 0.602 AU over every revolution.

One full revolution takes 1.46 yr (532 days), computed from the semi-major axis of 1.285 AU.

An eccentricity of 0.234 makes the orbit moderately elongated.

The orbital plane is tilted 16.79° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 33.4 km/s at perihelion and falls to 20.7 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 = 21.9 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.15 km.

Observation record and orbit quality

Astrometry from 72 individual observations underpins this orbit; the fit leaves an RMS residual of 0.6424 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
1.285 AU
Eccentricity
0.234
Perihelion
0.984 AU
Aphelion
1.58569 AU
Inclination
16.79°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
330.59°

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
2030-Jul-26 01:20 0.408602 AU
61125978 km
8.99 km/s
2031-Jan-18 12:19 0.423628 AU
63373876 km
18.14 km/s
2033-Aug-26 19:55 0.177988 AU
26626683 km
10.63 km/s
2034-Jan-20 19:18 0.204296 AU
30562187 km
9.13 km/s
2046-Jul-12 11:16 0.491229 AU
73486738 km
9.09 km/s
2049-Aug-22 12:58 0.189981 AU
28420733 km
9.09 km/s
2050-Jan-14 23:14 0.162985 AU
24382213 km
10.32 km/s
2052-Aug-20 21:43 0.454804 AU
68037738 km
18.66 km/s
2053-Feb-19 06:48 0.436226 AU
65258440 km
9.25 km/s
2065-Aug-11 16:17 0.285545 AU
42716899 km
8.77 km/s
2066-Jan-14 11:36 0.247861 AU
37079425 km
13.30 km/s
2068-Aug-25 13:51 0.303220 AU
45361132 km
14.47 km/s
2069-Feb-04 04:10 0.330625 AU
49460823 km
9.07 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
21.9

Orbit Quality

RMS
0.64244
Condition
0
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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