NGC 7331 — Sbc in Pegasus
Sbc in Pegasus, 9.3 arcminutes across, its light 39 million years old. Measured by HyperLEDA, photographed by Pan-STARRS1. Recorded once.
About NGC 7331
NGC 7331 is often called the Milky Way's twin. It is a spiral of similar size and type, and astronomers have studied it as a guide to what our own galaxy might look like from outside. A small group of much more distant galaxies lies in the same field of view, known to amateur astronomers as the Deer Lick Group, though they are not related to it.
What you are looking at
NGC 7331 is a spiral of the same broad class astronomers give the Milky Way: a moderate bulge and clearly drawn arms. Its disc is steeply tilted, about 70° from face-on, so it appears as a long oval. From edge to edge its visible disc spans about 106,000 light-years (taking its redshift distance, which for a galaxy this near is approximate), close to the width of the Milky Way.
What astronomers have recorded
SIMBAD, the reference database astronomers use, classes it as a LINER galaxy: its nucleus shows the faint, low-level activity of a black hole feeding slowly. Patrick Moore listed it as Caldwell 30 in his 1995 catalogue of the finest deep-sky objects for amateur observers. Three supernovae have been recorded in it, the first in 1959; the most recent include SN 1959D, SN 2013bu, SN 2014C. It is cited in 1,295 scientific papers indexed by SIMBAD, and recorded there under 24 different catalogue designations.
When this light set out
The light that reaches us from NGC 7331 today set out about 39 million years ago, when the planet had come through its hottest interval since the dinosaurs. The galaxy is moving away from us at about 816 km/s (1.8 million mph), carried by the expansion of the universe. For a galaxy this close, its own motion through space is a large share of that speed, so the distance worked out from it is approximate; distances measured from individual stars in it can differ.
Finding it in the sky
In the sky, NGC 7331 sits within the constellation Pegasus. It is best placed on autumn evenings: around 9:30 pm in October it stands about 84° high in the south, seen from the middle of the United States.
Its neighbours
At almost the same distance from us, and so its neighbours in space as well as on the sky: NGC 7320 (0.5° away on the sky, at least 350,000 light-years from it); UGC 12060 (1.5° away on the sky, at least 1,010,000 light-years from it); UGC 12082 (1.7° away on the sky, at least 1,140,000 light-years from it).
By apparent size it is number 21 of the 12,657 galaxies on the Galaxy Origins register.
Measurements
| Catalogue | PGC 69327 |
|---|---|
| Morphological type | Sbc |
| Angular diameter | 9.27′ |
| Right ascension | 22h37m04.1s |
| Declination | +34°24′56.2″ |
| Constellation | Pegasus |
| Inclination | 70.0° |
| Light travel time | 39 million years |
| Bar | not recorded |
Check every figure above in the NASA/IPAC Extragalactic Database
What is sold
A print of this galaxy and the record of the calculation, once. When it sells it leaves the register and is not offered again. We assign no names and no ownership — nobody can sell you those.
At 9.3 arcminutes this is a Exceptional galaxy, which is the tier where a real photograph shows clear structure and dust lanes. The tier comes from the measured diameter, not from a price list.
Take this galaxy — $1,290 Browse the Collection