NGC 1140 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Eridanus |
Right ascension | 02h 54m 33.542s[1] |
Declination | −10° 01′ 42.60″[1] |
Redshift | 0.005007[2] |
Heliocentric radial velocity | 1150 km/s[2] |
Distance | 59.47 ± 4.18 Mly (18.233 ± 1.283 Mpc)[2] |
Apparent magnitude (V) | 12.25[2] |
Apparent magnitude (B) | 12.84[3] |
Absolute magnitude (V) | −19.05[2] |
Characteristics | |
Type | IBm pec[2] |
Apparent size (V) | 1.7′ × 0.9′[2] |
Notable features | Wolf–Rayet galaxy |
Other designations | |
Markarian 1063, VV 482, MCG-02-08-019, PGC 10966[3] |
NGC 1140 is an irregular galaxy in the southern constellation of Eridanus. Estimates made using the Tully–Fisher method put the galaxy at about 59 million light years (18 megaparsecs).[2] It was discovered on 22 November 1786 by William Herschel, and was described as "pretty bright, small, round, stellar" by John Louis Emil Dreyer, the compiler of the New General Catalogue.[4]
NGC 1140 is a starburst galaxy, meaning it is forming stars at a very fast rate. In fact, while it is only a tenth as wide as the Milky Way, it is producing stars at a rate of 0.65 M☉/yr,[5] about the same as the Milky Way. The image taken by the Hubble Space Telescope shows bright blue and red regions of star formation, similar to NGC 1569.[6] The starburst is estimated to have begun about 5 million years ago.[5] Its low metallicity (the ratio of hydrogen and helium to other elements) makes NGC 1140 similar to primordial galaxies.[6]
Wolf–Rayet stars, a class of blue, massive, and luminous stars, are present in this galaxy; in fact, NGC 1140 has so many of them that their spectra also appear in the galaxy's spectrum.[5] These types of galaxies are known Wolf–Rayet galaxies, and are fairly rare because Wolf–Rayet stars are a short stage in the lives of very massive stars.[7]