SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 XU3

2018 XU3

2018 XU3 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.584 AU it takes 1.99 yr to circle the Sun.

Apollo Observations: 47
Orbital Period · P
1.99 yr
v(q)
36.2 km/s
v(Q)
15.5 km/s
Diameter · ≈
0.03 km
TJ
4.27
Eccentricity · e
0.4012

Orbit and dynamics

Between its closest point (0.949 AU) and its farthest (2.22 AU), the heliocentric distance changes by 1.271 AU over every revolution.

One full revolution takes 1.99 yr (728 days), computed from the semi-major axis of 1.584 AU.

The high eccentricity (0.401) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 13.21° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 36.2 km/s at perihelion and falls to 15.5 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 = 25.48 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.03 km.

Observation record and orbit quality

Astrometry from 47 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4851 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
1.584 AU
Eccentricity
0.4012
Perihelion
0.949 AU
Aphelion
2.219501 AU
Inclination
13.21°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
252.93°

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
2026-Dec-08 23:07 0.069578 AU
10408657 km
11.61 km/s
2028-Dec-04 19:31 0.118495 AU
17726642 km
12.87 km/s
2029-Apr-05 08:21 0.440193 AU
65851955 km
5.23 km/s
2030-Dec-01 07:38 0.180455 AU
26995696 km
14.46 km/s
2031-Apr-13 23:14 0.480304 AU
71852452 km
6.48 km/s
2032-Nov-27 00:09 0.244841 AU
36627722 km
16.20 km/s
2034-Nov-23 14:32 0.317765 AU
47536908 km
18.12 km/s
2036-Nov-19 04:43 0.391456 AU
58560966 km
20.16 km/s
2038-Nov-15 20:19 0.465396 AU
69622295 km
22.23 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
25.48

Orbit Quality

RMS
0.48514
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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