AAS 207th Meeting, 8-12 January 2006
Session 171 Supernovae
Poster, Thursday, 9:20am-4:00pm, January 12, 2006, Exhibit Hall

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[171.14] The Effects of Spectral Lines on Magnitudes and Colors of Type Ia Supernovae

N. R. Hall, D. Branch, E. Baron (The University of Oklahoma)

The photometric diversity among Type Ia supernovae (SNe Ia) is partly a result of differences in fundamental explosion properties such as the mass of freshly synthesized radioactive nickel, which controls the brightness and temperature, and partly a result of differences in the spectral features. Near maximum light the spectral features form in the outer layers of the ejecta and therefore may differ even for two events that have the same nickel mass and bolometric luminosity. The quantitative effects of spectral lines on magnitudes and colors are considered. Fits to observed SN Ia spectra obtained with the parameterized supernova synthetic-spectrum code SYNOW are used in an attempt to isolate the effects of the spectral features on UBVRI magnitudes and colors. For example, the effects of the evolution of the spectral features on the Phillips light-curve decline-rate parameter are estimated, these effects are removed from the observed decline-rate parameters, and the resulting "line--free" photometric behavior of SNe Ia is investigated. This sort of analysis may prove to be useful in advancing our physical understanding of SNe Ia, and improving their effectiveness as distance indicators.

The author(s) of this abstract have provided an email address for comments about the abstract: nicholashall@ou.edu

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