NGC 4157 — SABb in Ursa Major
SABb in Ursa Major, 6.6 arcminutes across, its light 37 million years old. Measured by HyperLEDA, photographed by Pan-STARRS1. Recorded once.
About NGC 4157
What you are looking at
NGC 4157 is a spiral with a sizeable central bulge and well-defined arms, close in type to the Milky Way. A weak bar of stars crosses its centre. Its disc is turned almost exactly side-on to us: the galaxy appears as a narrow blade of light, and its dust as a dark seam running along it. From edge to edge its visible disc spans about 71,000 light-years (taking its redshift distance, which for a galaxy this near is approximate), about 73% of the Milky Way’s width.
What astronomers have recorded
SIMBAD, the reference database astronomers use, classes it as a member of a cluster of galaxies. Three supernovae have been recorded in it, the first in 1937; the most recent include SN 1937A, SN 1955A, SN 2003J. It is cited in 381 scientific papers indexed by SIMBAD, and recorded there under 36 different catalogue designations.
When this light set out
What a telescope records of NGC 4157 is light that left it about 37 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 778 km/s (1.7 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 4157 sits within the constellation Ursa Major. From most of the United States it never sets: it circles the north celestial pole all year, and stands highest on spring evenings, around May.
Its neighbours
At almost the same distance from us, and so its neighbours in space as well as on the sky: UGC 7176 (0.2° away on the sky, at least 130,000 light-years from it); NGC 4088 (0.9° away on the sky, at least 570,000 light-years from it); NGC 4085 (0.9° away on the sky, at least 600,000 light-years from it); UGC 7267 (1.1° away on the sky, at least 720,000 light-years from it), and 13 more.
By apparent size it is number 56 of the 12,657 galaxies on the Galaxy Origins register.
Measurements
| Catalogue | PGC 38795 |
|---|---|
| Morphological type | SABb |
| Angular diameter | 6.58′ |
| Right ascension | 12h11m04.3s |
| Declination | +50°29′05.9″ |
| Constellation | Ursa Major |
| Inclination | 90.0° |
| Light travel time | 37 million years |
| Bar | yes, from the catalogue |
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 6.6 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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