| NGC 3998 | |
|---|---|
 SDSS image of NGC 3998 | |
| Observation data (J2000 epoch) | |
| Constellation | Ursa Major |
| Right ascension | 11h 57m 56.1333s[1] |
| Declination | +55° 27′ 12.922″[1] |
| Redshift | 0.00350[1] |
| Heliocentric radial velocity | 1048 ± 5 km/s[1] |
| Distance | 45 Mly (13.7 Mpc)[2] |
| Apparent magnitude (V) | 12.10[3] |
| Apparent magnitude (B) | 11.64[4] |
| Absolute magnitude (V) | 2.7′ × 2.3′[5] |
| Characteristics | |
| Type | SA00(r):[1] |
| Other designations | |
| UGC 6946, MCG +09-20-046, PGC 37642[1] | |
NGC 3998 is a lenticular galaxy located in the constellation Ursa Major. It was discovered on April 14, 1789, by the astronomer William Herschel.[5] At a distance of 45 million light-years (13.7 megaparsecs),[2] it is located relatively nearby, making it a well-studied object.[6]
In Gérard de Vaucouleurs' atlas of galaxy morphological types, NGC 3998 has a classification of SA00(r):, meaning it is unbarred and has an internal ring.[5] It is classified as a LINER-type galaxy.[6] As an early-type galaxy, NGC 3998's stars are relatively old and reddish in color, but its nuclear region may still have signs of star formation with stars less than 10 million years old.[6] The galaxy's shape is very round, and also oblate.[2]
- ^ a b c d e f "Results for object NGC 3998 (NGC 3998)". NASA/IPAC Extragalactic Database. California Institute of Technology. Retrieved 2021-04-25.
- ^ a b c Cite error: The named reference
Walshwas invoked but never defined (see the help page). - ^ Véron-Cetty, M.-P.; Véron, P. (2010). "A catalogue of quasars and active nuclei". Astronomy and Astrophysics. 518 (13th ed.): A10. Bibcode:2010A&A...518A..10V. doi:10.1051/0004-6361/201014188.
- ^ "NGC 3998". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-04-25.
- ^ a b c Seligman, Courtney. "New General Catalogue objects: NGC 3950 - 3999". cseligman.com. Retrieved 2021-04-25.
- ^ a b c Cite error: The named reference
Frankwas invoked but never defined (see the help page).