Part 1: Supernova as Standard Candles


Though Type II supernovae can vary significantly in brightness, all type Ia supernovae have approximately the same absolute magnitude after their light curves have been corrected for the timescaleа“аstretch-factor” . The image below shows this correction. аThis is due to the process in which they supernovae occurs. аType Ia supernovae occur when a white dwarf accumulates too much mass to resist the force of gravity. аThis always occurs when the mass of the star reaches the Chandrasekhar Limit of 1.4 solar masses. а

Since type Ia supernovae have a known brightness they can be used as standard candles to determine the distance to a galaxy once the stretch-factor is accounted for. а

In this section, you will be given a series of images for a galaxy with a supernova explosion. аUsing the series of images, make a light curveаof the supernova explosions. аUsing the light curves, determine the apparent magnitude of the supernova at its peak brightness and then find the distance to the galaxy.

Given the redshift to the host galaxy, determine the Hubble constant

where v is the velocity, c is the speed of light, and z is the redshift. Then, determine the age of the universe at this redshift.

Using the Cosmo Calculator, check your answer for the age at that redshift.

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