NGC 2787

NGC 2787
NGC 2787 as observed by the Hubble Space Telescope (HST).
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension09h 19m 18.60430s[1]
Declination+69° 12′ 11.6429″[1]
Heliocentric radial velocity627.3±13.2 km/s[2]
Distance24.17 ± 0.46 Mly (7.41 ± 0.14 Mpc)[3]
Apparent magnitude (V)11.79[4]
Apparent magnitude (B)12.92[4]
Absolute magnitude (B)−18.84[5]
Characteristics
TypeSB(r)0+[6]
Mass/Light ratio50[5] M☉/L☉
Size5.5 kpc[5]
Apparent size (V)2′.530 × 1′.518[7] (NIR)
Notable featuresBarred lenticular; LINER
Other designations
PGC 26341, UGC 4914[8]
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NGC 2787 is a barred lenticular galaxy approximately 24[3] million light-years away in the northern constellation of Ursa Major. It was discovered on December 3, 1788 by German-born astronomer William Herschel. J. L. E. Dreyer described it as, "bright, pretty large, a little extended 90°, much brighter middle, mottled but not resolved, very small (faint) star involved to the southeast".[9] The visible galaxy has an angular size of 2.5 × 1.5 arcminutes[7] or 3.24 × 1.81 arcminutes[10] and an apparent visual magnitude of 11.8.[4]

This galaxy is small and isolated[5] with a morphological classification of SB(r)0+,[6] which indicates a barred spiral (SB) with a ring around the bar (r). Being a lenticular galaxy, it has the large halo of an elliptical galaxy. The disk is inclined at an angle of 58°±3° to the line of sight from the Earth, with the major axis aligned along a position angle of 110°±3°.[5] The galaxy has an unusually high mass-to-light ratio, much greater than for a typical spiral galaxy.[5] The distribution of the galaxy's neutral hydrogen forms a clumpy ring with a radius of 10.3 kpc, double that of the visible galaxy, with a mass of 5.5×108 M☉.[5] This ring appears misaligned with the central disk.[11]

NGC 2787 contains a low-ionization nuclear emission-line region (LINER) at its core, which is a type of region that is characterized by its spectral line emission from weakly ionized atoms.[12] LINERs are very common within lenticular galaxies, with approximately one-fifth of nearby lenticular galaxies containing LINERs.[13] The supermassive black hole at the center has a mass of 4.1+0.4
−0.5×107 M☉.[14] The central region of the galaxy contains dust rings that are tilted with respect to the disk, which may be the result of an encounter with another galaxy.[11]

  1. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Bosch2015 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Tully2013 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference Véron-Cetty2010 was invoked but never defined (see the help page).
  5. ^ a b c d e f g Cite error: The named reference Shostak1987 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Erwin2013 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Skrutskie2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference ned was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Seligman was invoked but never defined (see the help page).
  10. ^ "NGC 2787 - Lenticular Galaxy in Ursa Major". The Sky Live. TheSkyLive.com. Retrieved 25 July 2023.
  11. ^ a b Cite error: The named reference Erwin2003 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference hoetal1997a was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference hoetal1997b was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Graham2008 was invoked but never defined (see the help page).