SpaceAtlas Space Object Data
NASA JPL SBDB · 401998

401998

401998 belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 1.969 AU it takes 2.76 yr to circle the Sun.

Apollo Observations: 309
Orbital Period · P
2.76 yr
v(q)
82.6 km/s
v(Q)
5.5 km/s
Diameter · ≈
0.74 km
TJ
3.2
Eccentricity · e
0.8759

Orbit and dynamics

Between its closest point (0.244 AU) and its farthest (3.694 AU), the heliocentric distance changes by 3.45 AU over every revolution.

One full revolution takes 2.76 yr (1,009 days), computed from the semi-major axis of 1.969 AU.

The high eccentricity (0.876) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

A steep inclination of 21.46° carries it well above and below the ecliptic plane.

By the vis-viva equation its orbital speed rises to 82.6 km/s at perihelion and falls to 5.5 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 = 18.42 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.74 km.

Observation record and orbit quality

Astrometry from 309 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4198 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
1.969 AU
Eccentricity
0.8759
Perihelion
0.244 AU
Aphelion
3.693647 AU
Inclination
21.46°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
95.41°

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

No close approaches to Earth are currently on record for this object.

Physical Parameters

Diameter
— km
Albedo
—
Density
— g/cm³
Rotation Period
— h
Absolute Magnitude
18.42

Orbit Quality

RMS
0.41978
Condition
0
Orbit ID
—
Data source: NASA JPL Small-Body Database . 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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