NGC 7217 — Sab in Pegasus
Sab in Pegasus, 4.5 arcminutes across, its light 46 million years old. Measured by HyperLEDA, photographed by Pan-STARRS1. Recorded once.
About NGC 7217
NGC 7217 is a spiral with tightly wound arms arranged in several rings. Part of its stars rotate in the opposite direction to the rest, a trace of an old merger.
What you are looking at
NGC 7217 is an early-type spiral: a large, bright central bulge wrapped in smooth, tightly wound arms. It is tilted about 33° to our line of sight, enough to show both the shape of its arms and the depth of its disc. From edge to edge its visible disc spans about 60,000 light-years (taking its redshift distance, which for a galaxy this near is approximate), about half 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. It is cited in 516 scientific papers indexed by SIMBAD, and recorded there under 24 different catalogue designations.
When this light set out
What a telescope records of NGC 7217 is light that left it about 46 million years ago; on Earth, the planet had come through its hottest interval since the dinosaurs. The galaxy is moving away from us at about 951 km/s (2.1 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
NGC 7217 lies in Pegasus. It is best placed on autumn evenings: around 9:30 pm in October it stands about 81° high in the south, seen from the middle of the United States.
By apparent size it is number 162 of the 12,657 galaxies on the Galaxy Origins register.
Measurements
| Catalogue | PGC 68096 |
|---|---|
| Morphological type | Sab |
| Angular diameter | 4.52′ |
| Right ascension | 22h07m52.4s |
| Declination | +31°21′33.3″ |
| Constellation | Pegasus |
| Inclination | 33.4° |
| Light travel time | 46 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 4.5 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.
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