SpaceAtlas Space Object Data
NASA JPL SBDB · 2015 ER

2015 ER

2015 ER belongs to the Apollo group of near-Earth asteroids, whose orbits cross the path of Earth; with a semi-major axis of 2.316 AU it takes 3.52 yr to circle the Sun.

Apollo Observations: 94
Orbital Period · P
3.52 yr
v(q)
61.6 km/s
v(Q)
6.2 km/s
Diameter · ≈
0.2 km
TJ
3
Eccentricity · e
0.8165

Orbit and dynamics

Between its closest point (0.425 AU) and its farthest (4.207 AU), the heliocentric distance changes by 3.782 AU over every revolution.

One full revolution takes 3.52 yr (1,287 days), computed from the semi-major axis of 2.316 AU.

The high eccentricity (0.817) produces a strongly elongated orbit, so the object spends most of its time far from the Sun.

The orbital plane is tilted 11.58° relative to the ecliptic.

By the vis-viva equation its orbital speed rises to 61.6 km/s at perihelion and falls to 6.2 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 = 21.2 and an assumed geometric albedo of 0.14, the diameter works out to roughly 0.2 km.

Observation record and orbit quality

Astrometry from 94 individual observations underpins this orbit; the fit leaves an RMS residual of 0.4535 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
2.316 AU
Eccentricity
0.8165
Perihelion
0.425 AU
Aphelion
4.207014 AU
Inclination
11.58°
Orbital Period
— yr
Epoch
2461200.5
Mean Anomaly
51.63°

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
2043-Aug-24 15:48 0.480506 AU
71882654 km
23.22 km/s
2050-Oct-16 21:28 0.166342 AU
24884361 km
27.05 km/s
2057-Oct-31 09:18 0.309062 AU
46235071 km
35.58 km/s
2061-Feb-20 20:59 0.475334 AU
71109027 km
42.27 km/s
2068-Mar-05 19:37 0.209227 AU
31299922 km
33.56 km/s
2075-Mar-27 13:46 0.232726 AU
34815311 km
21.15 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
21.2

Orbit Quality

RMS
0.45351
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.

Keep exploring

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