SpaceAtlas Space Object Data
NASA JPL SBDB · 2020 HJ4

2020 HJ4

2020 HJ4 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 2.07 AU it takes 2.98 yr to circle the Sun.

Apollo Observations: 88
Orbital Period · P
2.98 yr
v(q)
40 km/s
v(Q)
10.7 km/s
Diameter · ≈
0.33 km
TJ
3.54
Eccentricity · e
0.5766

Orbit and dynamics

Between its closest point (0.876 AU) and its farthest (3.264 AU), the heliocentric distance changes by 2.388 AU over every revolution.

One full revolution takes 2.98 yr (1,088 days), computed from the semi-major axis of 2.07 AU.

The high eccentricity (0.577) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

Its inclination of 1.22° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 40 km/s at perihelion and falls to 10.7 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 = 20.15 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.33 km.

Observation record and orbit quality

Astrometry from 88 individual observations underpins this orbit; the fit leaves an RMS residual of 0.5929 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
2.07 AU
Eccentricity
0.5766
Perihelion
0.876 AU
Aphelion
3.263562 AU
Inclination
1.22°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
321.65°

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
2032-Oct-27 09:27 0.085525 AU
12794410 km
14.88 km/s
2035-Oct-20 03:25 0.021008 AU
3142685 km
12.43 km/s
2038-Oct-07 19:17 0.069398 AU
10381750 km
10.64 km/s
2041-Sep-25 19:25 0.099090 AU
14823614 km
10.12 km/s
2044-Sep-06 09:37 0.125713 AU
18806404 km
10.27 km/s
2047-Aug-21 09:12 0.124108 AU
18566285 km
10.22 km/s
2050-Aug-01 22:42 0.095878 AU
14343120 km
10.18 km/s
2053-Jul-23 15:10 0.063902 AU
9559531 km
10.50 km/s
2056-Jul-16 12:05 0.034075 AU
5097549 km
11.25 km/s
2059-Jul-18 00:09 0.036875 AU
5516492 km
11.15 km/s
2062-Jul-20 23:21 0.053654 AU
8026466 km
10.78 km/s
2065-Aug-03 13:00 0.092233 AU
13797935 km
10.01 km/s
2068-Aug-19 06:32 0.117185 AU
17530614 km
10.09 km/s
2071-Sep-07 14:39 0.118063 AU
17661964 km
10.09 km/s
2074-Sep-22 04:25 0.101549 AU
15191493 km
10.02 km/s
2077-Oct-08 00:26 0.053068 AU
7938820 km
10.60 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
20.15

Orbit Quality

RMS
0.59289
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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