SpaceAtlas Space Object Data
NASA JPL SBDB · 2011 HR4

2011 HR4

2011 HR4 is an Aten-type near-Earth asteroid whose orbit lies mostly inside that of Earth, with a semi-major axis of 0.914 AU and a period of 0.87 yr.

Aten Observations: 11
Orbital Period · P
0.87 yr
v(q)
39.2 km/s
v(Q)
24.8 km/s
Diameter · ≈
0.04 km
TJ
6.5
Eccentricity · e
0.2248

Orbit and dynamics

The path is an ellipse reaching 0.708 AU from the Sun at perihelion and 1.119 AU at aphelion, a radial span of 0.411 AU.

Applying Kepler's third law to a = 0.914 AU gives an orbital period of 0.87 yr, or about 319 days.

An eccentricity of 0.225 makes the orbit moderately elongated.

The orbital plane is tilted 8.13° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 39.2 km/s at perihelion and falls to 24.8 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 = 24.55 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.04 km.

Observation record and orbit quality

The current orbit solution is based on 11 observations and has a weighted RMS residual of 0.6995 arcseconds.

Condition code U = 9 signals a poorly constrained orbit, so its future path should be treated as provisional.

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
0.9137 AU
Eccentricity
0.2248
Perihelion
0.708 AU
Aphelion
1.1191 AU
Inclination
8.13°
Orbital Period
— yr
Epoch
2455678.5
Mean Anomaly
177.01°

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-Mar-09 12:31 0.117837 AU
17628185 km
14.01 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
24.55

Orbit Quality

RMS
0.69954
Condition
9
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.

Keep exploring

Explore asteroids, comets and near-Earth objects with JPL orbital data.