SpaceAtlas Space Object Data
NASA JPL SBDB · 2021 FN

2021 FN

2021 FN belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.037 AU it takes 1.06 yr to circle the Sun.

Apollo Observations: 50
Orbital Period · P
1.06 yr
v(q)
38.9 km/s
v(Q)
22 km/s
Diameter · ≈
0.08 km
TJ
5.8
Eccentricity · e
0.2777

Orbit and dynamics

The path is an ellipse reaching 0.749 AU from the Sun at perihelion and 1.325 AU at aphelion, a radial span of 0.576 AU.

Applying Kepler's third law to a = 1.037 AU gives an orbital period of 1.06 yr, or about 386 days.

An eccentricity of 0.278 makes the orbit moderately elongated.

A steep inclination of 24.35° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 38.9 km/s at perihelion and falls to 22 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 = 23.22 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.08 km.

Observation record and orbit quality

The current orbit solution is based on 50 observations and has a weighted RMS residual of 0.5433 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
1.037 AU
Eccentricity
0.2777
Perihelion
0.749 AU
Aphelion
1.324975 AU
Inclination
24.35°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
217.84°

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
2038-Apr-03 22:42 0.372130 AU
55669893 km
21.63 km/s
2039-Apr-06 15:02 0.170186 AU
25459448 km
14.82 km/s
2040-Mar-23 20:44 0.264135 AU
39513989 km
12.94 km/s
2040-Jul-30 00:35 0.403709 AU
60394063 km
14.24 km/s
2041-Mar-01 06:27 0.425872 AU
63709598 km
12.80 km/s
2041-Sep-15 13:10 0.238886 AU
35736811 km
15.82 km/s
2042-Oct-21 07:58 0.212815 AU
31836680 km
17.43 km/s
2043-Nov-17 14:05 0.440917 AU
65960270 km
23.76 km/s
2057-Apr-05 12:40 0.279099 AU
41752662 km
19.57 km/s
2058-Apr-04 14:48 0.169752 AU
25394517 km
13.86 km/s
2059-Mar-19 06:54 0.300793 AU
44997994 km
12.94 km/s
2059-Aug-14 18:00 0.349437 AU
52274986 km
15.36 km/s
2060-Feb-22 10:53 0.450852 AU
67446473 km
12.52 km/s
2060-Sep-26 01:21 0.204275 AU
30559168 km
15.88 km/s
2061-Oct-29 15:12 0.244644 AU
36598194 km
18.78 km/s
2076-Apr-06 13:54 0.202902 AU
30353779 km
17.35 km/s
2077-Mar-31 18:51 0.189283 AU
28316370 km
13.24 km/s
2078-Mar-12 13:21 0.342235 AU
51197662 km
12.95 km/s
2078-Aug-28 11:07 0.293194 AU
43861268 km
15.77 km/s
2079-Feb-12 16:03 0.479930 AU
71796468 km
11.98 km/s
2079-Oct-07 08:36 0.192097 AU
28737238 km
16.20 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
23.22

Orbit Quality

RMS
0.54334
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.

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