SpaceAtlas Space Object Data
NASA JPL SBDB · 2015 WM16

2015 WM16

2015 WM16 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 2.755 AU it takes 4.57 yr to circle the Sun.

Apollo Observations: 27
Orbital Period · P
4.57 yr
v(q)
41 km/s
v(Q)
7.9 km/s
Diameter · ≈
0.18 km
TJ
2.79
Eccentricity · e
0.6783

Orbit and dynamics

The path is an ellipse reaching 0.886 AU from the Sun at perihelion and 4.624 AU at aphelion, a radial span of 3.738 AU.

Applying Kepler's third law to a = 2.755 AU gives an orbital period of 4.57 yr, or about 1,670 days.

The high eccentricity (0.678) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 32.4° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 41 km/s at perihelion and falls to 7.9 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

The measured diameter is 0.39 km, a value from direct size determination rather than from brightness alone.

Its geometric albedo of 0.022 indicates a very dark, carbonaceous-type surface.

Observation record and orbit quality

The current orbit solution is based on 27 observations and has a weighted RMS residual of 0.3703 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
2.755 AU
Eccentricity
0.6783
Perihelion
0.886 AU
Aphelion
4.623717 AU
Inclination
32.4°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
115.64°

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
2056-Dec-16 20:43 0.265978 AU
39789786 km
29.83 km/s

Distances in astronomical units (AU) and kilometres. Source: NASA/JPL CNEOS Close Approach Data API.

Physical Parameters

Diameter
0.392 km
Albedo
0.022
Density
— g/cm³
Rotation Period
— h
Absolute Magnitude
21.48

Orbit Quality

RMS
0.37025
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.

Keep exploring

Explore asteroids, comets and near-Earth objects with JPL orbital data.