SpaceAtlas Space Object Data
NASA JPL SBDB · 161999

161999

161999 is an Amor-type near-Earth asteroid that approaches Earth from beyond our orbit without crossing it, orbiting the Sun at 2.317 AU once every 3.53 yr.

Amor Observations: 156
Orbital Period · P
3.53 yr
v(q)
34.5 km/s
v(Q)
11.1 km/s
Diameter · ≈
0.62 km
TJ
3.38
Eccentricity · e
0.5136

Orbit and dynamics

The path is an ellipse reaching 1.127 AU from the Sun at perihelion and 3.507 AU at aphelion, a radial span of 2.38 AU.

Applying Kepler's third law to a = 2.317 AU gives an orbital period of 3.53 yr, or about 1,288 days.

The high eccentricity (0.514) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 7.39° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 34.5 km/s at perihelion and falls to 11.1 km/s at aphelion.

Its perihelion lies just outside Earth's orbit, which is why it is classed as Earth-approaching rather than Earth-crossing.

Size and surface

The measured diameter is 0.46 km, a value from direct size determination rather than from brightness alone.

A geometric albedo of 0.211 points to a comparatively bright, reflective surface.

Observation record and orbit quality

The current orbit solution is based on 156 observations and has a weighted RMS residual of 0.4658 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
2.317 AU
Eccentricity
0.5136
Perihelion
1.127 AU
Aphelion
3.507011 AU
Inclination
7.39°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
164.82°

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
0.458 km
Albedo
0.211
Density
— g/cm³
Rotation Period
— h
Absolute Magnitude
18.8

Orbit Quality

RMS
0.46579
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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