| NGC 5398 | |
|---|---|
 NGC 5398 imaged by theHubble Space Telescope; Tol 89 is the pale red patch to the lower left of center | |
| Observation data (J2000epoch) | |
| Constellation | Centaurus |
| Right ascension | 14h 01m 21.555s[1] |
| Declination | −33° 03′ 49.62″[1] |
| Heliocentric radial velocity | 1,219 km/s[2] |
| Galactocentric velocity | 1,085 km/s[2] |
| Distance | 27.8 Mly (8.5 Mpc)[3] |
| Apparent magnitude (V) | 12.6[4] |
| Characteristics | |
| Type | SB(rs)dm[4] |
| Apparent size (V) | 2.8′ × 1.7′[4] (D25) |
| Other designations | |
| IRAS 13584-3249,NGC 5398,UGCA 379,LEDA 49923,MCG -05-33-037,PGC 49923[5][4] | |
NGC 5398 is abarred spiral galaxy in the southernconstellation ofCentaurus. It was discovered June 3, 1836 byJohn Herschel.[6] Distance estimates range from5.39 Mpc to18.30 Mpc. Thetip of the red-giant branch method yields a distance of11.6 Mpc,[7] while theTully–Fisher relation shows values of around8.5 Mpc.[3] It is receding with a heliocentricradial velocity of1,219 km/s.[2]
Themorphological class of NGC 5398 is SB(rs)dm,[8] indicating this is a spiral galaxy with an inner bar (SB) and incomplete ring (rs) structures, plus broken, irregularspiral arms (dm). Thegalactic plane is inclined at an angle of 53° to the line of sight from the Earth. The oval outline of the disk has anangular size of2.8′ × 1.7′ at a limiting magnitude of 25, with the major axis aligned along aposition angle of 172°.[9]
At the southwestern end of the bar lies a giantH II region (GHR) designated Tol 89. It spans a region of1.7 × 1.2 kpc with an absolute magnitude of −14.8 in theB (blue) band, making it "one of the most impressive GHRs known". This is the only large site in NGC 5398 that is undergoingstar formation, and it suggests that NGC 5398 is engaged in some form ofinteraction.[10][11][12]
Media related toNGC 5398 at Wikimedia Commons