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Comet

IRAS-Araki-Alcock

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C/1983 H1 (IRAS-Araki-Alcock)

IRAS-Araki-Alcock is a comet in the Comet orbit class. Its orbit takes it from 0.99 AU to 195.08 AU from the Sun; one orbit takes 970.7 years; it is about 9.20 km across. Orbit from the JPL solution of 15 April 2021.

Where is it now

Distance from Sun
63.393 AU
True anomaly
168.18°
Distance from Earth
62.448 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 IRAS-Araki-Alcock — 63.393 AU from the Sun IRAS-Araki-Alcock
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. IRAS-Araki-Alcock is 62.448 AU from Earth today (8.7 light-hours).

In the sky

Right ascension
03h 07m 45s
Declination
+18° 36′ 45″
Constellation
Aries
Distance from Earth
62.45 AU
Elongation from the Sun
162.42° — near opposition — up most of the night

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
98.034 AU
Eccentricity
0.9899
Inclination
73.25°
Orbital period
970.7 years
Perihelion
0.991 AU
Aphelion
195.077 AU
Longitude of ascending node
49.1°
Argument of periapsis
192.85°
Epoch · J2000
2445467.5
Orbit class · COM
Comet
Earth MOID · 2.3 LD
0.0058 AU
Tisserand (Jupiter)
0.408

Orbit quality

Orbit reasonably well determined (uncertainty code 4).

Observations used
347
Data arc
160 days
First observed
27 April 1983
Last observed
4 October 1983
Residual RMS
0.77 ″
Solution · Otto Matic
15 April 2021

Physical properties

Mean radius
4.60 km

Visual & observation

Geometric albedo
0.02

Discovery & classification

Also known as 1983 H1 · C/1983 H1 · 1983 VII · 1983d

Named

Sources