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Asteroid Near-Earth

2021 CD1

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(2021 CD1)

Where is it now

Distance from Sun
1.195 AU
True anomaly
165.43°
Distance from Earth
1.151 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 CD1 — 1.195 AU from the Sun 2021 CD1
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 CD1 is 1.151 AU from Earth today (9.6 light-minutes).

In the sky

Right ascension
10h 11m 37s
Declination
+34° 07′ 27″
Constellation
Leo Minor
Distance from Earth
1.15 AU
Elongation from the Sun
67.46° — well clear of the Sun

Favours the northern hemisphere; low or below the horizon from far south.

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
0.896 AU
Eccentricity
0.358
Inclination
25.25°
Orbital period
309.8 days
Perihelion
0.575 AU
Aphelion
1.217 AU
Longitude of ascending node
320.66°
Argument of periapsis
319.07°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 25.1 LD
0.0646 AU
Tisserand (Jupiter)
6.508

Orbit quality

Orbit poorly determined (uncertainty code 7).

Observations used
45
Data arc
14 days
First observed
5 February 2021
Last observed
19 February 2021
Residual RMS
0.44 ″
Solution · Otto Matic
15 April 2021

Visual & observation

Absolute magnitude (H)
24.13

Discovery & classification

Aten Near-Earth Object

Close approaches 40 on record

Flyby geometry
Ecliptic flyby of 2021 CD1 at 2027-02-07 21:19 UTC Top-down view of the ecliptic, Earth at the centre, for the 2027-02-07 21:19 UTC close approach of 2021 CD1. Catalogue miss distance 139.3 LD · 5.35 × 10⁷ km. The curve is the geocentric path from 2027-02-04 to 2027-02-10, 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 south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 139.3 LD · 5.35 × 10⁷ km 2027-02-07 21:19 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2027-02-07 21:19 UTC close approach of 2021 CD1. Catalogue miss distance 139.3 LD · 5.35 × 10⁷ km. The curve is the geocentric path from 2027-02-04 to 2027-02-10, 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 south 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
2027-02-07 21:19:00 Earth 0.3578 AU 139.3 LD 24.6 km/s
2030-10-30 00:00:00 Earth 0.4573 AU 178.0 LD 20.5 km/s
2031-07-27 11:40:00 Earth 0.4374 AU 170.2 LD 21.3 km/s
2032-02-11 23:40:00 Earth 0.1598 AU 62.2 LD 13.9 km/s
2036-09-20 13:05:00 Earth 0.356 AU 138.6 LD 18.3 km/s
2038-02-12 10:20:00 Earth 0.2008 AU 78.1 LD 20.1 km/s
2042-08-13 04:28:00 Earth 0.3979 AU 154.9 LD 20.6 km/s
2043-02-02 06:07:00 Earth 0.2793 AU 108.7 LD 13.5 km/s
2049-02-14 15:24:00 Earth 0.0729 AU 28.4 LD 16.5 km/s
2055-02-06 14:34:00 Earth 0.3976 AU 154.7 LD 25.7 km/s

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

Sources