SpaceAtlas Space Object Data
NASA JPL SBDB · 494999

494999

494999 is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.919 AU and a period of 0.88 yr.

Aten Observations: 267
Orbital Period · P
0.88 yr
v(q)
57.4 km/s
v(Q)
16.8 km/s
Diameter · ≈
0.41 km
TJ
6.23
Eccentricity · e
0.546

Orbit and dynamics

The path is an ellipse reaching 0.417 AU from the Sun at perihelion and 1.421 AU at aphelion, a radial span of 1.004 AU.

Applying Kepler's third law to a = 0.919 AU gives an orbital period of 0.88 yr, or about 322 days.

The high eccentricity (0.546) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 36.22° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 57.4 km/s at perihelion and falls to 16.8 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 = 19.69 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.41 km.

Observation record and orbit quality

The current orbit solution is based on 267 observations and has a weighted RMS residual of 0.4513 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
0.9191 AU
Eccentricity
0.546
Perihelion
0.417 AU
Aphelion
1.420929 AU
Inclination
36.22°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
245.22°

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
2034-Jun-25 10:03 0.048002 AU
7180980 km
24.08 km/s
2049-Jun-20 06:18 0.187373 AU
28030628 km
27.52 km/s
2056-Jun-28 07:24 0.071551 AU
10703861 km
21.55 km/s
2071-Jun-25 19:58 0.047356 AU
7084315 km
24.08 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
19.69

Orbit Quality

RMS
0.45126
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.

Keep exploring

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