Astronomy:SN 1998S

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SN 1998S
SN1998S.jpg
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]
Spectral classIIn
DateMarch 2, 1998 by Z. Wan.
ConstellationUrsa Major
Right ascension11h 46m 06.25s
Declination+47° 28' 55.5"
EpochJ2000.0
Galactic coordinates150.7467 +65.9637
Distance17 Mpc
HostNGC 3877
ProgenitorUnknown
Progenitor typemaybe Red supergiant
Colour (B-V)~ 0.2 mag
Notable featuresSN 1998S, AAVSO 1140+48
Peak apparent magnitude12 mag

SN 1998S was a type IIn supernova that was observed in NGC 3877 in March 1998. SN 1998S was the brightest type IIn event observed .[2]

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.[3]

References

  1. Fassia, A.; Meikle, W. P. S.; Vacca, W. D.; Kemp, S. N.; Walton, N. A.; Pollacco, D. L.; Smartt, S.; Oscoz, A. et al. (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. doi:10.1046/j.1365-8711.2000.03797.x. Bibcode2000MNRAS.318.1093F. 
  2. Fassia, A.; Meikle, W. P. S.; Chugai, N.; Geballe, T. R.; Lundqvist, P.; Walton, N. A.; Pollacco, D.; Veilleux, S. et al. (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. doi:10.1046/j.1365-8711.2001.04282.x. Bibcode2001MNRAS.325..907F. 
  3. Dessart, Luc (2015). "Numerical simulations of super-luminous supernovae of type IIn". MNRAS 449 (4): 4304–4325. doi:10.1093/mnras/stv609. Bibcode2015MNRAS.449.4304D. 

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