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Asteroid Near-Earth

2021 KM

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(2021 KM)

Where is it now

Distance from Sun
0.942 AU
True anomaly
241.01°
Distance from Earth
0.833 AU
As of
20 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 KM — 0.942 AU from the Sun 2021 KM
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 KM is 0.833 AU from Earth today (6.9 light-minutes).

In the sky

Right ascension
17h 54m 46s
Declination
-17° 13′ 31″
Constellation
Sagittarius
Distance from Earth
0.83 AU
Elongation from the Sun
61.08° — well clear of the Sun

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
0.889 AU
Eccentricity
0.3373
Inclination
6.82°
Orbital period
306.3 days
Perihelion
0.589 AU
Aphelion
1.189 AU
Longitude of ascending node
210.84°
Argument of periapsis
244.68°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 11.3 LD
0.0291 AU
Tisserand (Jupiter)
6.624

Orbit quality

Orbit poorly determined (uncertainty code 7).

Observations used
23
Data arc
2 days
First observed
17 May 2021
Last observed
19 May 2021
Residual RMS
0.35 ″
Solution · Otto Matic
19 May 2021

Visual & observation

Absolute magnitude (H)
25.58

Discovery & classification

Aten Near-Earth Object

Close approaches 178 on record

Flyby geometry
Ecliptic flyby of 2021 KM at 2026-12-28 02:21 UTC Top-down view of the ecliptic, Earth at the centre, for the 2026-12-28 02:21 UTC close approach of 2021 KM. Catalogue miss distance 156.6 LD · 6.02 × 10⁷ km. The curve is the geocentric path from 2026-12-25 to 2026-12-31, 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 156.6 LD · 6.02 × 10⁷ km 2026-12-28 02:21 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2026-12-28 02:21 UTC close approach of 2021 KM. Catalogue miss distance 156.6 LD · 6.02 × 10⁷ km. The curve is the geocentric path from 2026-12-25 to 2026-12-31, 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
2026-12-28 02:21:00 Earth 0.4025 AU 156.6 LD 14.7 km/s
2027-08-17 21:29:00 Earth 0.1771 AU 68.9 LD 13.4 km/s
2031-02-03 17:05:00 Venus 0.1115 AU 43.4 LD 16.5 km/s
2031-05-17 06:57:00 Earth 0.3552 AU 138.2 LD 20.1 km/s
2032-01-20 05:19:00 Earth 0.3923 AU 152.7 LD 13.7 km/s
2032-08-22 07:58:00 Earth 0.1167 AU 45.4 LD 7.9 km/s
2037-02-12 23:25:00 Earth 0.3547 AU 138.1 LD 11 km/s
2037-07-15 04:57:00 Earth 0.2025 AU 78.8 LD 6.9 km/s
2040-04-25 01:34:00 Venus 0.1484 AU 57.8 LD 18.3 km/s
2042-11-05 01:17:00 Earth 0.3372 AU 131.2 LD 11.1 km/s

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

Sources