SpaceAtlas Space Object Data
NASA JPL SBDB · 2012 HN40

2012 HN40

2012 HN40 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 2.706 AU it takes 4.45 yr to circle the Sun.

Apollo Observations: 115
Orbital Period · P
4.45 yr
v(q)
40.8 km/s
v(Q)
8 km/s
Diameter · ≈
0.28 km
TJ
2.96
Eccentricity · e
0.6712

Orbit and dynamics

The path is an ellipse reaching 0.89 AU from the Sun at perihelion and 4.522 AU at aphelion, a radial span of 3.632 AU.

Applying Kepler's third law to a = 2.706 AU gives an orbital period of 4.45 yr, or about 1,626 days.

The high eccentricity (0.671) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 14.38° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 40.8 km/s at perihelion and falls to 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 = 20.49 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.28 km.

Observation record and orbit quality

The current orbit solution is based on 115 observations and has a weighted RMS residual of 0.5473 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
2.706 AU
Eccentricity
0.6712
Perihelion
0.89 AU
Aphelion
4.522267 AU
Inclination
14.38°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
41.69°

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
2052-Oct-09 15:28 0.335543 AU
50196461 km
22.47 km/s
2061-Jul-26 00:39 0.249568 AU
37334796 km
11.86 km/s
2070-May-30 05:38 0.136113 AU
20362228 km
18.44 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
20.49

Orbit Quality

RMS
0.54734
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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