SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 HH2

2018 HH2

2018 HH2 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.248 AU it takes 1.39 yr to circle the Sun.

Apollo Observations: 119
Orbital Period · P
1.39 yr
v(q)
33.6 km/s
v(Q)
21.1 km/s
Diameter · ≈
0.08 km
TJ
5.07
Eccentricity · e
0.2276

Orbit and dynamics

Between its closest point (0.964 AU) and its farthest (1.532 AU), the heliocentric distance changes by 0.568 AU over every revolution.

One full revolution takes 1.39 yr (509 days), computed from the semi-major axis of 1.248 AU.

An eccentricity of 0.228 makes the orbit moderately elongated.

The orbital plane is tilted 18.61° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 33.6 km/s at perihelion and falls to 21.1 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 = 23.12 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.08 km.

Observation record and orbit quality

Astrometry from 119 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4433 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
1.248 AU
Eccentricity
0.2276
Perihelion
0.964 AU
Aphelion
1.532045 AU
Inclination
18.61°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
332.7°

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
2031-Dec-10 12:11 0.291530 AU
43612249 km
13.07 km/s
2032-Apr-29 01:20 0.281269 AU
42077271 km
9.89 km/s
2038-Dec-10 01:07 0.384235 AU
57480805 km
16.75 km/s
2049-Oct-27 12:18 0.407319 AU
60934029 km
10.71 km/s
2050-May-16 17:41 0.395078 AU
59102788 km
20.94 km/s
2056-Nov-07 14:12 0.331299 AU
49561578 km
10.50 km/s
2057-May-09 06:24 0.212386 AU
31772493 km
16.72 km/s
2063-Nov-19 03:24 0.274218 AU
41022454 km
10.25 km/s
2064-May-02 16:19 0.083041 AU
12422758 km
13.12 km/s
2070-Nov-28 05:47 0.250814 AU
37521253 km
10.25 km/s
2071-Apr-28 15:17 0.061493 AU
9199273 km
10.74 km/s
2077-Dec-05 23:17 0.250366 AU
37454285 km
11.00 km/s
2078-Apr-25 13:44 0.139444 AU
20860492 km
9.66 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
23.12

Orbit Quality

RMS
0.44331
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

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