NGC 1140

NGC 1140
NGC 1140, imaged by Hubble
Observation data (J2000 epoch)
Constellation Eridanus
Right ascension 02h 54m 33.542s[1]
Declination −10° 01′ 42.60″[1]
Redshift 0.005007[2]
Helio 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 began 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 have short lives.[7]

References

  1. 1 2 Cutri, R. M. (2003). "2MASS All-Sky Catalog of Point Sources". VizieR On-line Data Catalog. Bibcode:2003yCat.2246....0C.
  2. 1 2 3 4 5 6 7 8 "NED results for object NGC 1140". National Aeronautics and Space Administration / Infrared Processing and Analysis Center. Retrieved 4 March 2017.
  3. 1 2 "NGC 1140". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 March 2017.
  4. ↑ Seligman, Courtney. "New General Catalogue objects: NGC 1100 - 1149". cseligman.com. Retrieved 4 March 2017.
  5. 1 2 3 Karthick, M. Chrisphin; López-Sánchez, Ángel R.; Sahu, D. K.; Sanwal, B. B.; Bisht, Shuchi (2014). "Photometric and spectroscopic studies of star-forming regions within Wolf-Rayet galaxies". Monthly Notices of the Royal Astronomical Society. 439 (1): 157–178. arXiv:1311.7504. Bibcode:2014MNRAS.439..157K. doi:10.1093/mnras/stt2301.
  6. 1 2 "A galactic nursery | ESA/Hubble". www.spacetelescope.org. 2015. Retrieved 4 March 2017.
  7. ↑ "Intense and short-lived | ESA/Hubble". www.spacetelescope.org. 2015. Retrieved 4 March 2017.
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