Skip to content
Public Universe
Asteroid Near-Earth

2021 OJ

Add to an observing list or journal →

(2021 OJ)

Where is it now

Distance from Sun
0.653 AU
True anomaly
73.49°
Distance from Earth
1.525 AU
As of
19 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Sun Earth — 0.996 AU from the Sun Earth 2021 OJ — 0.653 AU from the Sun 2021 OJ
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 OJ is 1.525 AU from Earth today (12.7 light-minutes).

In the sky

Right ascension
12h 39m 20s
Declination
-20° 35′ 45″
Constellation
Corvus
Distance from Earth
1.53 AU
Elongation from the Sun
17.96° — too close to the Sun to observe

Favours the southern hemisphere; low or below the horizon from far north.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
0.865 AU
Eccentricity
0.3983
Inclination
42.81°
Orbital period
293.6 days
Perihelion
0.52 AU
Aphelion
1.209 AU
Longitude of ascending node
303.89°
Argument of periapsis
167.03°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 65.2 LD
0.1676 AU
Tisserand (Jupiter)
6.567

Orbit quality

Orbit very well determined (uncertainty code 1).

Observations used
31
Data arc
7.93 years
First observed
15 August 2017
Last observed
19 July 2025
Residual RMS
0.72 ″
Solution · Otto Matic
21 July 2025

Visual & observation

Absolute magnitude (H)
22.54

Discovery & classification

Aten Near-Earth Object

Close approaches 22 on record

Flyby geometry
Ecliptic flyby of 2021 OJ at 2058-07-31 06:38 UTC Top-down view of the ecliptic, Earth at the centre, for the 2058-07-31 06:38 UTC close approach of 2021 OJ. Catalogue miss distance 73.4 LD · 2.82 × 10⁷ km. The curve is the geocentric path from 2058-07-28 to 2058-08-03, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is north of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 73.4 LD · 2.82 × 10⁷ km 2058-07-31 06:38 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2058-07-31 06:38 UTC close approach of 2021 OJ. Catalogue miss distance 73.4 LD · 2.82 × 10⁷ km. The curve is the geocentric path from 2058-07-28 to 2058-08-03, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. At closest approach the object is north of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.

JPL Horizons

When (UTC) Body Distance Lunar distances Relative speed
2058-07-31 06:38:00 Earth 0.1885 AU 73.4 LD 20.9 km/s
2062-07-30 04:59:00 Earth 0.1682 AU 65.4 LD 20.3 km/s
2066-07-28 14:51:00 Earth 0.1821 AU 70.9 LD 20 km/s
2099-07-31 16:46:00 Earth 0.1882 AU 73.2 LD 20.9 km/s
2103-07-31 14:28:00 Earth 0.1682 AU 65.5 LD 20.3 km/s
2107-07-30 00:12:00 Earth 0.1827 AU 71.1 LD 20 km/s
2140-08-01 02:13:00 Earth 0.1869 AU 72.7 LD 20.9 km/s
2144-07-30 23:07:00 Earth 0.1683 AU 65.5 LD 20.3 km/s
2148-07-29 08:37:00 Earth 0.184 AU 71.6 LD 20 km/s
2181-08-01 11:55:00 Earth 0.186 AU 72.4 LD 20.9 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources