NGC 278

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]
Preview warning: Page using Template:Infobox galaxy with unknown parameter "image_size"
Preview warning: Page using Template:Infobox galaxy with unknown parameter "absmag_b"

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]

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]

  1. ^ a b c d e f Cite error: The named reference ned was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Sánchez-Gil2015 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i Cite error: The named reference Israel2009 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference knappen2004 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Seligman was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference garrido2003 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference hoetal1997 was invoked but never defined (see the help page).