NGC 3198
NGC 3198 is a barred spiral galaxy located approximately 47 million light-years away in the constellation Ursa Major. It is a member of the Ursa Major Group, a loose group of galaxies associated with the Ursa Major Cluster.
Characteristics:
NGC 3198 is classified as a SBbc galaxy, indicating it is a spiral galaxy (S) with a bar-shaped structure across its center (B), and loosely wound spiral arms (bc). The galaxy is known for its extended and relatively flat rotation curve, meaning the orbital speed of stars and gas remains nearly constant even at large distances from the galactic center. This observation provided early evidence for the existence of dark matter, suggesting that a significant amount of unseen mass is responsible for the galaxy's gravitational effects.
The galaxy contains a relatively low amount of neutral hydrogen gas (HI) compared to similar spiral galaxies. The HI gas distribution is also somewhat unusual, showing a warp in the outer regions. This distortion could be caused by interactions with other galaxies in the Ursa Major Group or by the accretion of intergalactic gas.
Discovery:
NGC 3198 was discovered by William Herschel on March 18, 1790.
Observational Data:
- Right Ascension: 10h 19m 54.8s
- Declination: +45° 33' 01"
- Redshift: 0.002467
- Apparent Magnitude: 10.2
- Size: Approximately 80,000 light-years in diameter.