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Comet

Schwassmann-Wachmann

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31P/Schwassmann-Wachmann 2

Where is it now

Distance from Sun
3.949 AU
True anomaly
280.3°
Distance from Earth
3.062 AU
As of
22 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.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.995 AU from the Sun Earth Schwassmann-Wachmann — 3.949 AU from the Sun Schwassmann-Wachmann
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Schwassmann-Wachmann is 3.062 AU from Earth today (25.5 light-minutes).

In the sky

Right ascension
03h 54m 57s
Declination
+15° 02′ 56″
Constellation
Taurus
Distance from Earth
3.06 AU
Elongation from the Sun
149.77° — 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
4.244 AU
Eccentricity
0.1931
Inclination
4.55°
Orbital period
8.74 years
Perihelion
3.424 AU
Aphelion
5.063 AU
Longitude of ascending node
114.19°
Argument of periapsis
17.93°
Epoch · J2000
2455668.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 949.5 LD
2.4399 AU
Tisserand (Jupiter)
2.993

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
1,042
Data arc
25.88 years
First observed
24 November 2000
Last observed
13 October 2026
Residual RMS
0.76 ″
Solution · Shantanu Naidu
14 October 2026

Physical properties

Mean radius
3.10 km

Visual & observation

Absolute magnitude (H)
4.4
Total magnitude M₁ · K₁ 22.5
4.4

Discovery & classification

Discovered by
Schwassmann, A. and Wachmann, A. A.
Discovery date
17 January 1929
Discovery site
Hamburg Observatory, Germany

Also known as 31P · 1929 I · 1929a · 1941f · 1942 I · 1947l · 1948 VII · 1954g

Named

Close approaches 12 on record

When (UTC) Body Distance Lunar distances Relative speed
2030-03-29 11:11:00 Juptr 1.3633 AU 530.6 LD 1.9 km/s
2033-11-28 03:33:00 Juptr 0.8388 AU 326.4 LD 4.4 km/s
2053-07-27 03:18:00 Juptr 1.9652 AU 764.8 LD 3.7 km/s
2057-05-24 09:31:00 Juptr 1.9118 AU 744.0 LD 7.4 km/s
2115-10-27 09:23:00 Juptr 0.8684 AU 338.0 LD 4.8 km/s
2119-07-09 01:45:00 Juptr 1.4343 AU 558.2 LD 2.7 km/s
2176-03-31 04:32:00 Jupiter 0.3515 AU 136.8 LD 3.5 km/s
2176-03-31 04:32:00 Juptr 0.3515 AU 136.8 LD 3.5 km/s

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

Sources