Sin asunto

a velocity of -3000 km/s is measured, significantly lower than that of SNe
2002cx and 2005hk (approximately -5000 km/s and constant for < 60 days;
Phillips et al. 2007, PASP, 119, 360).
     The spectrum does not have a red continuum, and there is no strong Na D
absorption in the spectrum, indicating that 2008ha is not heavily reddened.
Assuming (a) a distance modulus of 31.2 +/- 0.5 mag -- derived from a redshift
of 1393 km/s from Yu et al. (1993, Ap.J. Suppl. 88, 383), and allowing for
several flow models; (b) small Milky Way and host-galaxy extinction; and (c)
that the unfiltered magnitudes reported on CBET 1567 approximate those of the
R band, SN 2008ha had an absolute red magnitude of M_R = -13 +/- 1 at peak.
SNe 2002cx and 2005hk had M_R = -17.6 and -18.3 mag, respectively.
Considering the extremely low absolute magnitude and low ejecta velocity,
which imply a very low total energy release, Foley et al. wonder if 2008ha is
a true supernova that destroyed the progenitor star; if it is, then 2008ha is
possibly the least luminous supernova ever observed.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2008 CBAT
2008 November 20                 (CBET 1576)              Daniel W. E. Green