AAVSO: American Association of Variable Star Observers
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Peak Supernova Luminosities and Cosmological Distance Determinations (Poster abstract)

Volume 28 number 1 (2000)

Diego Rodriguez

Abstract

(Abstract only) It is well known that supernova light curves are useful to obtain distances to galaxies beyond the limit of Cepheid variables. In this paper we present work by the amateur supernova observers in the M1Supernova Search group of the Madrid Astronomical Association during the year 1998, work done which we think will be interesting for this purpose. We are aware of the need to obtain measurements of the supernova as close as possible to the moment of maximum brightness. Still, we find that the values of absolute magnitude inferred from our measurements, and from the accepted distances to parent galaxies, differ significantly from theoretical predictions in a number of cases. Thus supernova 1998S, if its distance is obtained from the reported red shift z of the host galaxy and the common value of Hubble’s constant, would be brighter than the accepted limit for a type Ia supernova. We have tried to fit the data to the standard theoretical magnitude by using the value of Ho that best leads to agreement in most cases. Even so, there are discrepancies that might support the view that type Ia supernova luminosities can differ by more than one magnitude.