M99 (NGC 4254) — Sc in Coma Berenices
Sc in Coma Berenices, 5.0 arcminutes across, its light 115 million years old. Measured by HyperLEDA, photographed by Pan-STARRS1. Recorded once.
About M99 (NGC 4254)
Messier 99 is a face-on spiral in the Virgo Cluster with one arm noticeably longer and looser than the other, a lopsidedness likely caused by an encounter with another galaxy. It was one of the first galaxies in which spiral structure was recognised, after the Whirlpool.
What you are looking at
M99 is a late-type spiral: a small central bulge and open, loosely wound arms full of young stars and star-forming gas. We look down on it almost face-on, so its structure is laid out as if on a map. From edge to edge its visible disc spans about 168,000 light-years, about 1.7 times the width of the Milky Way.
What astronomers have recorded
SIMBAD, the reference database astronomers use, classes it as an HII galaxy, glowing with clouds of hydrogen lit by young stars. Four supernovae have been recorded in it, the first in 1967; the most recent include SN 1972Q, SN 1986I, SN 2014L. It is cited in 1,031 scientific papers indexed by SIMBAD, and recorded there under 49 different catalogue designations.
When this light set out
What a telescope records of M99 is light that left it about 115 million years ago; on Earth, the first flowering plants had appeared. The galaxy is moving away from us at about 2,407 km/s (5.4 million mph), carried by the expansion of the universe.
Finding it in the sky
M99 lies in Coma Berenices. It is best placed on spring evenings: around 9:30 pm in May it stands about 64° high in the south, seen from the middle of the United States.
Its neighbours
It lies in the direction of the Virgo Cluster and at a matching speed, which places it among the cluster’s more than a thousand galaxies, the nearest large cluster to the Milky Way. At almost the same distance from us, and so its neighbours in space as well as on the sky: IC 3061 (1.0° away on the sky, at least 1,980,000 light-years from it); NGC 4189 (1.6° away on the sky, at least 3,160,000 light-years from it); NGC 4193 (1.7° away on the sky, at least 3,460,000 light-years from it); IC 3099 (2.0° away on the sky, at least 4,020,000 light-years from it), and 6 more.
By apparent size it is number 122 of the 12,657 galaxies on the Galaxy Origins register.
Measurements
| Catalogue | PGC 39578 |
|---|---|
| Morphological type | Sc |
| Angular diameter | 5.04′ |
| Right ascension | 12h18m49.6s |
| Declination | +14°25′00.5″ |
| Constellation | Coma Berenices |
| Inclination | 20.1° |
| Light travel time | 115 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 5.0 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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