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NGC 3198

Coordinates: Sky map 10h 19m 54.99s, +45° 32′ 58.88″
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(Redirected from Herschel 146)
NGC 3198
NGC 3198 imaged by GALEX (ultraviolet)
Observation data (J2000 epoch)
ConstellationUrsa Major
Right ascension10h 19m 54.99s[1]
Declination+45° 32′ 58.88″[1]
Redshift0.00227[1]
Distance47 Mly[2]
Apparent magnitude (V)10.3[3]
Characteristics
TypeSB(rs)c[3]
Apparent size (V)8′.5 × 3′.3[3]
Other designations
UGC 5572, MCG +08-19-020, PGC 30197[1]

NGC 3198, also known as Herschel 146[4] is a barred spiral galaxy in the constellation Ursa Major. It was discovered by William Herschel on 15 January 1788.[5][2] NGC 3198 is located in the Leo Spur,[2] which is part of the Virgo Supercluster,[6] and is approximately 47 million light years away.[2]

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).[7]

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.[8]

Supernovae

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Two supernovae have been observed in NGC 3198:

  • SN 1966J (type Ia, mag. 13)[9] was discovered on 20 December 1966. Some sources list this supernova as a type Ib.[2]
  • At magnitude 17.8, SN 1999bw was significantly fainter than expected when discovered, and was initially classified as a Type IIn supernova.[10] In 2021, researchers reclassified it as a gap transient.[11][12]
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See also

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References

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  1. ^ a b c d "NGC 3198". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 July 2015.
  2. ^ a b c d e O'Meara, Stephen James (2011). Deep-Sky Companions: The Secret Deep, Volume 4. Photographs by Mario Motta. Cambridge University Press. pp. 186–188. ISBN 978-1-139-50007-4.
  3. ^ a b c Bratton, Mark (2011). The Complete Guide to the Herschel Objects. Cambridge University Press. p. 440. ISBN 978-0-521-76892-4.
  4. ^ Clark, Maurice. "Herschel 146 / NGC 3198". Herschel 400 List Objects. Retrieved 2017-01-25.
  5. ^ Seligman, Courtney. "New General Catalogue Objects: NGC 3198". Celestial Atlas. Retrieved 31 August 2024.
  6. ^ Monks, Neale (2010). Go-To Telescopes Under Suburban Skies. Springer. p. 53. ISBN 978-1-4419-6851-7.
  7. ^ a b 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". The Astrophysical Journal. 514 (2): 614–636. Bibcode:1999ApJ...514..614K. doi:10.1086/306989.
  8. ^ a b Gentile, G. (2013). "HALOGAS: Extraplanar gas in NGC 3198". Astronomy & Astrophysics. 554: A125. arXiv:1304.4232. Bibcode:2013A&A...554A.125G. doi:10.1051/0004-6361/201321116. S2CID 56047203.
  9. ^ "SN 1966J". Transient Name Server. IAU. Retrieved 31 August 2024.
  10. ^ Bishop, David. "Supernova 1999bw in NGC 3198". Astronomy Section Rochester Academy of Science. Retrieved 25 January 2017.
  11. ^ Ransome, C. L.; Habergham-Mawson, S. M.; Darnley, M. J.; James, P. A.; Filippenko, A. V.; Schlegel, E. M. (2021). "A systematic reclassification of Type IIn supernovae". Monthly Notices of the Royal Astronomical Society. 506 (4): 4715–4734. arXiv:2107.02179. doi:10.1093/mnras/stab1938.
  12. ^ "AT 1999bw". Transient Name Server. IAU. Retrieved 31 August 2024.
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  • Media related to NGC 3198 at Wikimedia Commons


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