SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 XD4

2018 XD4

2018 XD4 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.693 AU it takes 2.20 yr to circle the Sun.

Apollo Observations: 11
Orbital Period · P
2.20 yr
v(q)
44.5 km/s
v(Q)
11.8 km/s
Diameter · ≈
0.03 km
TJ
4
Eccentricity · e
0.5813

Orbit and dynamics

The path is an ellipse reaching 0.709 AU from the Sun at perihelion and 2.677 AU at aphelion, a radial span of 1.968 AU.

Applying Kepler's third law to a = 1.693 AU gives an orbital period of 2.20 yr, or about 805 days.

The high eccentricity (0.581) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

Its inclination of 3.9° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 44.5 km/s at perihelion and falls to 11.8 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 = 25.3 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 11 observations and has a weighted RMS residual of 0.3802 arcseconds.

Condition code U = 9 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
1.693 AU
Eccentricity
0.5813
Perihelion
0.709 AU
Aphelion
2.677141 AU
Inclination
3.9°
Orbital Period
— yr
Epoch
2458466.5
Mean Anomaly
24.73°

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
25.3

Orbit Quality

RMS
0.38019
Condition
9
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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