NGC 3198 explained
| NGC 3198 |
| Type: | SB(rs)c[1] |
| Ra: | [2] |
| Dist Ly: | 47 Mly |
| Z: | 0.00227 |
| Appmag V: | 10.3 |
| Size V: | 8′.5 × 3′.3 |
| Constellation Name: | Ursa Major |
NGC 3198, also known as Herschel 146[3] is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on 15 January 1788.[4] [5] NGC 3198 is located in the Leo Spur, which is part of the Virgo Supercluster,[6] and is approximately 47 million light years away.[5]
NGC 3198 was one of 18 galaxies targeted by the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale, which aimed to calibrate various secondary distance indicators and determine the Hubble constant to an accuracy of 10%. The type and orientation of NGC 3198 made it suitable for these measurements.[7] The Wide Field and Planetary Camera 2 (WFPC2) of the HST was used to measure the magnitudes of 52 Cepheid variables, and the resulting distance modulus corresponded to a distance of 14.5 Mpc (47 million light years).
Observations made with the Westerbork Synthesis Radio Telescope detected for the first time the presence of extraplanar gas.[8] The extraplanar gas makes up approximately 15% of the total atomic hydrogen (HI) mass of the galaxy.
Supernovae
Two supernovae have been observed in NGC 3198:
- SN 1966J (typeIa, mag. 13)[9] was discovered by Paul Wild on 18 December 1966.[10] Some sources list this supernova as a typeIb.[5]
- At magnitude 17.8, SN 1999bw was significantly fainter than expected when discovered, and was initially classified as a Type IIn supernova.[11] In 2021, researchers reclassified it as a gap transient.[12] [13]
See also
Notes and References
- Book: Bratton . Mark . 2011 . The Complete Guide to the Herschel Objects . 440 . . 978-0-521-76892-4.
- NGC 3198 . 5 July 2015.
- Web site: Clark . Maurice . Herschel 146 / NGC 3198 . Herschel 400 List Objects . 2017-01-25.
- Web site: New General Catalogue Objects: NGC3198 . Seligman . Courtney . Celestial Atlas . 31 August 2024 .
- Book: O'Meara, Stephen James
. Photographs by Mario Motta . 2011 . Deep-Sky Companions: The Secret Deep, Volume 4 . 186–188 . . 978-1-139-50007-4.
- Book: Monks . Neale . 2010 . Go-To Telescopes Under Suburban Skies . 53 . . 978-1-4419-6851-7.
- Kelson . Daniel . 1999 . The Hubble Space Telescope Key Project on the Extragalactic Distance Scale. XIX. The Discovery of Cepheids in and a New Distance to NGC 3198 . . 514 . 2 . 614–636 . 1999ApJ...514..614K . 10.1086/306989. free .
- Gentile . G. . 2013 . HALOGAS: Extraplanar gas in NGC 3198 . . 554 . A125 . 1304.4232 . 10.1051/0004-6361/201321116 . 2013A&A...554A.125G . 56047203 .
- Web site: Transient Name Server . SN1966J . . 31 August 2024.
- Web site: Circular No. 1986 . Gingerich . Owen . 22 December 1966 . Central Bureau for Astronomical Telegrams . Smithsonian Astrophysical Observatory . 2 December 2024.
- Web site: Bishop . David . Supernova 1999bw in NGC 3198 . Astronomy Section Rochester Academy of Science . 25 January 2017.
- 2107.02179. 10.1093/mnras/stab1938. free. A systematic reclassification of Type IIn supernovae. 2021. Ransome. C. L.. Habergham-Mawson. S. M.. Darnley. M. J.. James. P. A.. Filippenko. A. V.. Schlegel. E. M.. Monthly Notices of the Royal Astronomical Society. 506. 4. 4715–4734.
- Web site: Transient Name Server . AT1999bw . . 31 August 2024.
