NGC 2787 | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Ursa Major |
Right ascension | 09h 19m 18.60430s [1] |
Declination | +69° 12′ 11.6429″ [1] |
Heliocentric radial velocity | 627.3±13.2 km/s [2] |
Distance | 24.17 ± 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 | |
Type | SB(r)0+ [6] |
Mass/Light ratio | 50 [5] M☉/ L☉ |
Size | 5.5 kpc [5] |
Apparent size (V) | 2′.530 × 1′.518 [7] ( NIR) |
Notable features | Barred lenticular; LINER |
Other designations | |
PGC 26341, UGC 4914 [8] |
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]
NGC 2787 | |
---|---|
Observation data ( J2000 epoch) | |
Constellation | Ursa Major |
Right ascension | 09h 19m 18.60430s [1] |
Declination | +69° 12′ 11.6429″ [1] |
Heliocentric radial velocity | 627.3±13.2 km/s [2] |
Distance | 24.17 ± 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 | |
Type | SB(r)0+ [6] |
Mass/Light ratio | 50 [5] M☉/ L☉ |
Size | 5.5 kpc [5] |
Apparent size (V) | 2′.530 × 1′.518 [7] ( NIR) |
Notable features | Barred lenticular; LINER |
Other designations | |
PGC 26341, UGC 4914 [8] |
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]