Distances to Supernovae

• Type Ia supernovae are “standard candles” just like Hubble’s Cepheid variables

• Some Type Ia supernovae are in galaxies with Cepheid variables but most are much farther away

• Decay time of light curve is correlated to absolute luminosity

• Good to 20% as a distance measure

Notes:

The Pleiades contains over 3000 stars, is about 400 light years away, and only 13 light years across. Quite evident in the above photograph are the blue reflection nebulae that surround the bright cluster stars. Low mass, faint, brown dwarfs have recently been found in the Pleiades.