SpaceAtlas Space Object Data
NASA JPL SBDB · 2018 FJ4

2018 FJ4

2018 FJ4 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.479 AU it takes 1.80 yr to circle the Sun.

Apollo Observations: 147
Orbital Period · P
1.80 yr
v(q)
36.8 km/s
v(Q)
16.3 km/s
Diameter · ≈
0.2 km
TJ
4.5
Eccentricity · e
0.3866

Orbit and dynamics

The path is an ellipse reaching 0.907 AU from the Sun at perihelion and 2.051 AU at aphelion, a radial span of 1.144 AU.

Applying Kepler's third law to a = 1.479 AU gives an orbital period of 1.80 yr, or about 657 days.

An eccentricity of 0.387 makes the orbit moderately elongated.

Its inclination of 1.23° keeps it close to the plane of the ecliptic.

By the vis-viva equation its orbital speed rises to 36.8 km/s at perihelion and falls to 16.3 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 = 21.21 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.2 km.

Observation record and orbit quality

The current orbit solution is based on 147 observations and has a weighted RMS residual of 0.5385 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
1.479 AU
Eccentricity
0.3866
Perihelion
0.907 AU
Aphelion
2.050781 AU
Inclination
1.23°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
118.54°

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
2027-Oct-06 01:46 0.108533 AU
16236282 km
12.27 km/s
2036-Oct-05 23:16 0.117735 AU
17612949 km
12.53 km/s
2045-Oct-09 18:03 0.168820 AU
25255090 km
14.07 km/s
2054-Oct-14 04:47 0.239462 AU
35823073 km
16.19 km/s
2063-Oct-18 20:35 0.320073 AU
47882225 km
18.58 km/s
2065-May-11 07:26 0.489580 AU
73240074 km
23.42 km/s
2072-Oct-22 09:02 0.404087 AU
60450497 km
21.08 km/s
2074-May-15 18:56 0.404658 AU
60535910 km
20.97 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
21.21

Orbit Quality

RMS
0.53848
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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