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Asteroid Near-Earth

2021 RK12

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(2021 RK12)

Where is it now

Distance from Sun
0.764 AU
True anomaly
73.59°
Distance from Earth
1.396 AU
As of
21 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 — 0.995 AU from the Sun Earth 2021 RK12 — 0.764 AU from the Sun 2021 RK12
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 RK12 is 1.396 AU from Earth today (11.6 light-minutes).

In the sky

Right ascension
15h 50m 37s
Declination
-24° 16′ 29″
Constellation
Scorpius
Distance from Earth
1.4 AU
Elongation from the Sun
32.2° — near the Sun — look low at dusk or dawn

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
0.918 AU
Eccentricity
0.3078
Inclination
8.82°
Orbital period
321.2 days
Perihelion
0.635 AU
Aphelion
1.2 AU
Longitude of ascending node
341.5°
Argument of periapsis
228.55°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 5.9 LD
0.0151 AU
Tisserand (Jupiter)
6.459

Orbit quality

Orbit poorly determined (uncertainty code 6).

Observations used
17
Data arc
4 days
First observed
9 September 2021
Last observed
13 September 2021
Residual RMS
0.73 ″
Solution · Otto Matic
23 February 2025

Visual & observation

Absolute magnitude (H)
26.09

Discovery & classification

Aten Near-Earth Object

Close approaches 60 on record

Flyby geometry
Ecliptic flyby of 2021 RK12 at 2028-09-01 21:06 UTC Top-down view of the ecliptic, Earth at the centre, for the 2028-09-01 21:06 UTC close approach of 2021 RK12. Catalogue miss distance 61.7 LD · 2.37 × 10⁷ km. The curve is the geocentric path from 2028-08-29 to 2028-09-04, 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. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 61.7 LD · 2.37 × 10⁷ km 2028-09-01 21:06 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2028-09-01 21:06 UTC close approach of 2021 RK12. Catalogue miss distance 61.7 LD · 2.37 × 10⁷ km. The curve is the geocentric path from 2028-08-29 to 2028-09-04, 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. 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
2028-09-01 21:06:00 Earth 0.1586 AU 61.7 LD 14.4 km/s
2030-04-27 06:35:00 Venus 0.0855 AU 33.3 LD 11 km/s
2036-06-23 02:31:00 Venus 0.1042 AU 40.6 LD 13.3 km/s
2042-08-20 05:10:00 Venus 0.1456 AU 56.7 LD 15.9 km/s
2043-09-02 20:50:00 Earth 0.0904 AU 35.2 LD 7.9 km/s
2044-12-26 09:25:00 Earth 0.1472 AU 57.3 LD 10.9 km/s
2050-05-15 03:32:00 Venus 0.1457 AU 56.7 LD 17.4 km/s
2050-09-01 11:33:00 Earth 0.1253 AU 48.8 LD 13.4 km/s
2056-07-11 07:57:00 Venus 0.0979 AU 38.1 LD 15.2 km/s
2062-09-07 00:40:00 Venus 0.0628 AU 24.4 LD 13.6 km/s

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

Sources