SN 1998S was a type IIn supernova that was observed 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]
Event type | Supernova |
---|---|
IIn | |
Date | March 2, 1998 by Z. Wan. |
Constellation | Ursa Major |
Right ascension | 11h 46m 06.25s |
Declination | +47° 28' 55.5" |
Epoch | J2000.0 |
Galactic coordinates | 150.7467 +65.9637 |
Distance | 17 Mpc |
Host | NGC 3877 |
Progenitor | Unknown |
Progenitor type | maybe Red supergiant |
Colour (B-V) | ~ 0.2 mag |
Notable features | SN 1998S, AAVSO 1140+48 |
Peak apparent magnitude | 12 mag |
Other designations | SN 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]