NGC 278

NGC 278 is an isolated[3] spiral galaxy in the northern circumpolar constellation of Cassiopeia, near the southern constellation boundary with Andromeda. It lies at a distance of approximately 39 megalight-years from the Milky Way, giving it a physical scale of 190 ly (58 pc) per arcsecond.[3] The galaxy was discovered on December 11, 1786 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "considerably bright, pretty large, round, 2 stars of 10th magnitude near".[5]

NGC 278
NGC 278 by HST
Observation data (J2000 epoch)
ConstellationCassiopeia
Right ascension00h 52m 04.3s[1]
Declination+47° 33′ 02″[1]
Redshift0.002090[2]
Heliocentric radial velocity627±1 km/s[1]
Distance39 Mly (12.1 Mpc)[3]
Group or clusterVirgo Supercluster[4]
Apparent magnitude (V)11.5[1]
Absolute magnitude (B)−19.6[2]
Characteristics
TypeSAB(rs)b[3]
Apparent size (V)2′.1 × 2′.0[2]
Other designations
UGC 528,[1] PGC 3051[1]

The morphological classification of this galaxy is SAB(rs)b,[3] which indicates a weak bar structure around the nucleus (SAB), an incomplete ring around the bar (rs), and moderately-tightly wound spiral arms (b). It is a relatively small, compact spiral[3] with a diameter of 23 kly (7 kpc),[2] multiple flocculent arms and a bright, dusty nucleus that does not appear to be active.[3] However, the neutral hydrogen in the galaxy is spread over a diameter five times larger than its visible size.[2]

Although it appears nearly face-on, the galactic plane is inclined by an angle of 28° to the line of sight from the Earth, with the major axis being oriented along a position angle of 116°.[3] The outer part of the disk appears to be warped, so that the major axis is not quite perpendicular to the minor axis,[6] and the morphology is somewhat disrupted.[2] The inner disk contains multiple intense star-forming regions.[3] This is taking place in an inner ring with a radius of 6.5 kly (2 kpc) that may have been triggered by a merger with a smaller companion.[4] It has an H II nucleus.[7]

References
  1. "NASA/IPAC Extragalactic Database". Results for NGC 278. Retrieved 2007-02-01.
  2. Sánchez-Gil, M. Carmen; et al. (December 2015). "Corrugated velocity patterns in the spiral galaxies: NGC 278, NGC 1058, NGC 2500 & UGC 3574". Monthly Notices of the Royal Astronomical Society. 454 (4): 3376–3390. arXiv:1509.07094. Bibcode:2015MNRAS.454.3376S. doi:10.1093/mnras/stv2206. S2CID 12601314.
  3. Israel, F. P. (November 2009). "CI and CO in nearby galaxy centers. The star-burst galaxies NGC 278, NGC 660, NGC 3628 NGC 4631, and NGC 4666". Astronomy and Astrophysics. 506 (2): 689–702. arXiv:0908.3586. Bibcode:2009A&A...506..689I. doi:10.1051/0004-6361/200811586. S2CID 5062672.
  4. Knapen, J. H.; et al. (August 2004). "The nuclear ring in the unbarred galaxy NGC 278: Result of a minor merger?". Astronomy & Astrophysics. 423 (2): 481–493. arXiv:astro-ph/0405107. Bibcode:2004A&A...423..481K. doi:10.1051/0004-6361:20034336. S2CID 5961530.
  5. Seligman, Courtney. "NGC Objects: NGC 250 - 299". Celestial Atlas. Retrieved 2020-09-07.
  6. Garrido, O.; et al. (February 2003). "GHASP: An Hα kinematic survey of spiral and irregular galaxies. II. Velocity fields and rotation curves of 15 galaxies". Astronomy & Astrophysics. 399: 51–61. Bibcode:2003A&A...399...51G. doi:10.1051/0004-6361:20021784.
  7. Ho, Luis C.; et al. (October 1997). "A Search for 'Dwarf' Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". Astrophysical Journal Supplement. Vol. 112, no. 2. pp. 315–390. arXiv:astro-ph/9704107. Bibcode:1997ApJS..112..315H. doi:10.1086/313041.
  • Media related to NGC 278 at Wikimedia Commons
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