NGC 55
Galaxy in the constellation Sculptor
From Wikipedia, the free encyclopedia
NGC 55, also known as the String of Pearls Galaxy,[7] is a Magellanic type barred spiral galaxy located about 6.5 million light-years away in the constellation Sculptor. It was discovered on 7 July 1826 by Scottish astronomer James Dunlop.[8] Along with its neighbor NGC 300, it is one of the closest galaxies to the Local Group, probably lying between the Milky Way and the Sculptor Group.[8] It has an estimated mass of (2.0 ± 0.4) × 1010 M☉.[9]
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| NGC 55 | |
|---|---|
Magellanic barred spiral galaxy NGC 55 imaged by the La Silla Observatory | |
| Observation data (J2000 epoch) | |
| Constellation | Sculptor[1] |
| Right ascension | 00h 14m 53.6s[2] |
| Declination | −39° 11′ 47.9″[2] |
| Redshift | 0.000437[2] |
| Heliocentric radial velocity | 131 ± 2 km/s[2] |
| Distance | 6.5 ± 0.65 Mly (2.00 ± 0.2 Mpc)[3][4] [a] |
| Apparent magnitude (V) | 7.87[5][6] |
| Characteristics | |
| Type | SB(s)m[2] |
| Mass | (2.0 ± 0.4) × 1010 M☉ |
| Size | ~68,500 ly (20.99 kpc) (estimated)[2] |
| Apparent size (V) | 32.4′ × 5.6′[2] |
| Other designations | |
| PGC 1014,[2] Caldwell 72, 2MASS J00145360-3911478, IRAS F00124-3929, ESO 293-50, MCG -07-01-013[5] | |
Nearby galaxies and group information
NGC 55 and the spiral galaxy NGC 300 have traditionally been identified as members of the Sculptor Group, a nearby group of galaxies in the constellation of the same name. However, recent distance measurements indicate that the two galaxies actually lie in the foreground.[10]
It is likely that NGC 55 and NGC 300 form a gravitationally bound pair.[4]
Visual appearance
The Webb Society Deep-Sky Observer's Handbook[11] writes the following about NGC 55: "Nearly edge-on and appears asymmetrical with some signs of dust near the bulge, which is diffuse, broad and somewhat elongated with the south edge sharp; southeast of the bulge it is strongly curved and lined with 4 or 5 faint knots; north edge of the curve is sharp." Burnham calls it "one of the outstanding galaxies of the southern heavens", somewhat resembling a smaller version of the Large Magellanic Cloud.[12] In September 1897, the famous New York comet hunter Lewis Swift observed the galaxy from Echo Mountain, California with a 16-inch refractor. He mistook the galaxy's faint eastern section as a new find (even though John Herschel had drawn it) and that is how it got cataloged as IC 1537.[13]
