SN 1998S was a type IIn supernova that was detected in NGC 3877 in March 1998. At the time of discovery, SN 1998S was the brightest type IIn event observed,[2] although later outshone by SN 2010jl.[3]

SN 1998S
R-band image of SN 1998S in NGC 3877 obtained on 1998 March 16.1 ut at t he Jacobus Kapteyn Telescope (JKT), La Palma (north is up and east is to the left).[1]
Event typeSupernova
IIn
Datec. 50.5 million years ago
(detected 2 March 1998 by Z. Wan)
ConstellationUrsa Major
Right ascension11h 46m 06.25s
Declination+47° 28' 55.5"
EpochJ2000.0
Galactic coordinates150.7467 +65.9637
Distancec. 50.5 million ly
HostNGC 3877
Progenitor typemaybe Red supergiant
Colour (B-V)~ 0.2 mag
Notable featuresSN 1998S, AAVSO 1140+48
Peak apparent magnitude12 mag
Other designationsSN 1998S, 2MASS J11460613+4728553, AAVSO 1140+48

It was discovered on 1998 March 2.68 UT in NGC 3877 by Z. Wan at a broadband (unfiltered) optical magnitude of +15.2.

Its spectrum showed prominent H and He emission lines with narrow peaks and broad wings, superimposed on a blue continuum. These narrow lines indicate the presence of a dense circumstellar medium (CSM) in the vicinity of the supernova. The high luminosity of SN1998S is due to the interaction of fast material (ejecta) with previously-expelled slowly-expanding material (CSM), which can more effectively convert kinetic energy of ejecta into radiation energy.[4]

References

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  1. ^ Fassia, A.; Meikle, W. P. S.; Vacca, W. D.; Kemp, S. N.; Walton, N. A.; Pollacco, D. L.; Smartt, S.; Oscoz, A.; Aragon-Salamanca, A.; Bennett, S.; Hawarden, T. G.; Alonso, A.; Alcalde, D.; Pedrosa, A.; Telting, J.; Arevalo, M. J.; Deeg, H. J.; Garzon, F.; Gomez-Roldan, A.; Gomez, G.; Gutierrez, C.; Lopez, S.; Rozas, M.; Serra-Ricart, M.; Zapatero-Osorio, M. R. (11 November 2000). "Optical and infrared photometry of the Type IIn SN 1998S: days 11-146". Monthly Notices of the Royal Astronomical Society. 318 (4): 1093–1104. arXiv:astro-ph/0006080. Bibcode:2000MNRAS.318.1093F. doi:10.1046/j.1365-8711.2000.03797.x. S2CID 3073301.
  2. ^ Fassia, A.; Meikle, W. P. S.; Chugai, N.; Geballe, T. R.; Lundqvist, P.; Walton, N. A.; Pollacco, D.; Veilleux, S.; Wright, G. S.; Pettini, M.; Kerr, T.; Puchnarewicz, E.; Puxley, P.; Irwin, M.; Packham, C.; Smartt, S. J.; Harmer, D. (11 August 2001). "Optical and infrared spectroscopy of the type IIn SN 1998S: days 3-127". Monthly Notices of the Royal Astronomical Society. 325 (3): 907–930. arXiv:astro-ph/0011340. Bibcode:2001MNRAS.325..907F. doi:10.1046/j.1365-8711.2001.04282.x. S2CID 119514186.
  3. ^ Ofek, E. O.; Zoglauer, A.; Boggs, S. E.; Barriere, N. M.; Reynolds, S. P.; Fryer, C. L.; Harrison, F. A.; Cenko, S. B.; Kulkarni, S. R.; Gal-Yam, A.; Arcavi, I.; Bellm, E.; Bloom, J. S.; Christensen, F.; Craig, W. W. (2014-01-06). "SN 2010jl: Optical to hard X-ray observations reveal an explosion embedded in a ten solar mass cocoon". The Astrophysical Journal. 781 (1): 42. arXiv:1307.2247. Bibcode:2014ApJ...781...42O. doi:10.1088/0004-637X/781/1/42. ISSN 0004-637X.
  4. ^ Dessart, Luc (2015). "Numerical simulations of super-luminous supernovae of type IIn". MNRAS. 449 (4): 4304–4325. arXiv:1503.05463. Bibcode:2015MNRAS.449.4304D. doi:10.1093/mnras/stv609. S2CID 54221511.
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