SN 1992bc and SN 1992bo: Evidence for intrinsic differences in type Ia supernova luminosities Academic Article uri icon


  • Based on the two best-observed Type Ia supernovae found in the Caln/Tololo Supernova Search, in this Letter we present convincing evidence that Type Ia supernovae with a fast rate of decline in the B band are intrinsically subluminous with respect to those with a slower decline rate. The effect is greater in the B band than in the I band. Specifically, we show that the two Type Ia supernovae SN 1992bc and SN 1992bo differ by 0.80 0.2 mag in their peak B absolute magnitudes, and by only 0.41 0.2 mag in the I band. SN 1992bc occurred in a spiral galaxy, whereas SN 1992bo exploded very far from the nucleus of a lenticular galaxy. These findings suggest the possibility that these two Type Ia supernovae may have had progenitors with significant physical differences. Both objects are normal Type Ia supernovae from a photometric and spectroscopic point of view. Even though these objects confirm the dependence of the absolute B magnitude on the rate of decline, that relation could be less pronounced than suggested recently by Phillips (1993).

published proceedings

  • Astrophysical Journal

author list (cited authors)

  • Maza, J., Hamuy, M., Phillips, M. M., Suntzeff, N. B., & Avils, R.

complete list of authors

  • Maza, J||Hamuy, M||Phillips, MM||Suntzeff, NB||Avil├ęs, R

publication date

  • April 1994