NGC 23

NGC 23
NGC 23
NGC 23 by HST
Observation data (J 2000.0 epoch)
ConstellationPegasus
Right ascension00h 09m 53.411s[1]
Declination+25° 55′ 25.46″[1]
Redshift0.015231[2]
Heliocentric radial velocity4,568 km/s[3]
Distance173.5 Mly (53.21 Mpc)[3]
Apparent magnitude (V)11.9 mag
Absolute magnitude (V)-21.85
Characteristics
TypeSBb[4]
Apparent size (V)1.9′ × 1.4′
Other designations
LEDA 698, UGC 89, Mrk 545, PGC 698, GC 9.[2][5]

NGC 23 is a spiral galaxy located in the northern constellation of Pegasus, around 173.5 megalight-years distant from the Milky Way.[3] It was discovered by William Herschel on 10 September 1784. In the Webb Society Deep-Sky Observer's Handbook,[6] the visual appearance of NGC 23 is described as follows:

Bright, extended ellipse; a bright nuclear structure is noticeably elongated; two weak spiral enhancements emerge from opposite sides of the nucleus, one curving towards a bright star attached on the south end. The galaxy is likely interacting with NGC 9.

The shape of this galaxy is described by its morphological classification of SBb, which indicates it is a barred spiral (SB) with spiral arms that are moderately tightly wound (b).[4] It is a luminous infrared galaxy with star-forming clumps.[7]

In 1958, supernova SN 1955C was discovered in NGC 23 using the Hale Telescope. On a photographic plate taken 23 October 1955 (three years prior), a bright star with a visual magnitude around 16 was located 10″ to the north and 10″ east of the galactic center. It was not present on a plate taken 60 days prior.[8]

  1. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference ned was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference tully2016 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference GarcíaLorenzo2015 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Webb was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Larson2020 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Sandage1959 was invoked but never defined (see the help page).