SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 AC4

2018 AC4

2018 AC4 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.286 AU it takes 1.46 yr to circle the Sun.

Apollo Observations: 33
Orbital Period · P
1.46 yr
v(q)
42.7 km/s
v(Q)
16.2 km/s
Diameter · ≈
0.03 km
TJ
4.86
Eccentricity · e
0.4504

Orbit and dynamics

The path is an ellipse reaching 0.707 AU from the Sun at perihelion and 1.865 AU at aphelion, a radial span of 1.158 AU.

Applying Kepler's third law to a = 1.286 AU gives an orbital period of 1.46 yr, or about 533 days.

The high eccentricity (0.45) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 24.04° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 42.7 km/s at perihelion and falls to 16.2 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 = 25.4 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.03 km.

Observation record and orbit quality

The current orbit solution is based on 33 observations and has a weighted RMS residual of 0.4135 arcseconds.

Condition code U = 8 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
1.286 AU
Eccentricity
0.4504
Perihelion
0.707 AU
Aphelion
1.865214 AU
Inclination
24.04°
Orbital Period
— yr
Epoch
2458132.5
Mean Anomaly
42.59°

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
2053-Jan-17 12:58 0.184119 AU
27543764 km
22.64 km/s
2056-Jan-03 04:38 0.253117 AU
37865753 km
12.89 km/s
2058-Jul-30 16:35 0.223335 AU
33410492 km
13.48 km/s
2061-Jul-04 07:28 0.050714 AU
7586688 km
23.62 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
25.4

Orbit Quality

RMS
0.41352
Condition
8
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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