NGC 6503
Spiral galaxy in the constellation Draco
From Wikipedia, the free encyclopedia
NGC 6503 is a field[8] dwarf spiral galaxy [dubious – discuss] in the northern constellation of Draco. It was discovered by German astronomer Arthur von Auwers on July 22, 1854.[5] The galaxy has an angular size of 7.1′ × 2.4′[7] and an apparent visual magnitude of 10.2.[5] It is located at the distance of 18 million light years away from the Milky Way galaxy.[4] NGC 6503 may form the remote tip of a long chain of galaxies that extends out into the Local Void, forming a galaxy filament spanning 26 million light-years (8 Mpc).[9]
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| NGC 6503 | |
|---|---|
| |
| Observation data (J2000 epoch) | |
| Constellation | Draco |
| Right ascension | 17h 49m 26.4207s[2] |
| Declination | +70° 08′ 39.587″[2] |
| Redshift | 0.000143[3] |
| Heliocentric radial velocity | 28[4] km/s |
| Distance | 20.9 ± 2.2 Mly (6.40 ± 0.66 Mpc)[4] |
| Apparent magnitude (V) | 10.2[5] |
| Characteristics | |
| Type | SAB:(s)bc[6] |
| Apparent size (V) | 7.1′ × 2.4′[7] |
| Other designations | |
| IRAS 17499+7009, 2MASX J17492651+7008396, UGC 11012, LEDA 60921, MCG +12-17-009[3] | |
The galactic plane of this galaxy is inclined at an angle of 78°±3° to the plane of the sky,[4] with the major axis of its oval profile being aligned along a position angle of 121°.[10] The morphological classification of NGC 6502 is SAB:(s)bc. This indicates a barred spiral galaxy (SAB:) with no inner ring structure (s) and moderately wound spiral arms (bc). However, the ':' notation indicates some uncertainty about the classification. Older works gave it a class of SA(s)bc; i.e. no bar.[6]
A possible bar system has been reported via infrared observations, being viewed end-on from the perspective of the Earth.[11][12] Ultraviolet observations show a young, inner star forming ring encircling the bar.[12] The ring has a radius between 1 and 2.5 kpc from the core.[13] There is a disk of neutral hydrogen that is larger in extent than the optical disk of the galaxy. This extra-planar gas is mostly the result of star formation activity, rather than cold gas that is being accreted.[14] There is evidence for a LINER-type or Seyfert 2 nucleus.[12]
NGC 6503 has one known satellite galaxy,[15] known as KK 242. With a stellar mass of about 3 million solar masses, KK 242 is on the border between a dwarf irregular galaxy (dIrr) and a dwarf spheroidal galaxy (dSph).[16]
Gallery
NGC 6503 by Hubble Space Telescope
NGC 6503 (HST)
NGC 6503 from Hubble.
