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Comet

Elenin

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C/2017 A3 (Elenin)

Elenin is a comet in the Comet orbit class. Its orbit takes it from 3.85 AU to 82.84 AU from the Sun; one orbit takes 285.4 years. Orbit from the JPL solution of 15 April 2021.

Where is it now

Distance from Sun
20.733 AU
True anomaly
135.04°
Distance from Earth
20.549 AU
As of
24 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 — 0.994 AU from the Sun Earth Elenin — 20.733 AU from the Sun Elenin
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Elenin is 20.549 AU from Earth today (2.8 light-hours).

In the sky

Right ascension
19h 17m 22s
Declination
+76° 22′ 43″
Constellation
Draco
Distance from Earth
20.55 AU
Elongation from the Sun
99.36° — 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
43.347 AU
Eccentricity
0.9111
Inclination
98.51°
Orbital period
285.4 years
Perihelion
3.855 AU
Aphelion
82.839 AU
Longitude of ascending node
97.9°
Argument of periapsis
304.11°
Epoch · J2000
2457794.5
Orbit class · COM
Comet
Earth MOID · 1,252.5 LD
3.2183 AU
Tisserand (Jupiter)
-0.232

Orbit quality

Orbit reasonably well determined (uncertainty code 3).

Observations used
186
Data arc
330 days
First observed
5 January 2017
Last observed
1 December 2017
Residual RMS
0.5 ″
Solution · Otto Matic
15 April 2021

Visual & observation

Absolute magnitude (H)
9.7
Total magnitude M₁ · K₁ 10
9.7

Discovery & classification

Also known as 2017 A3

Named

Sources