Examples of these objects found in the bottom-left corner of an HR diagram include DAV and ZZ Ceti.
Examples of these objects found in the bottom-left corner of an HR diagram include DAV and ZZ Ceti. The transition between helium 1+ and 2+ drives the kappa mechanism, which powers the behavior of some of these objects. Henrietta Leavitt discovered one type of these stars and Harlow Shapley used another type to calculate the size of the Milky Way. PeriodÂ–luminosity relations are commonly determined for these stars. Examples of them used as standard candles to calculate astronomic differences are RR Lyrae and Cepheids. Found on the instability strip of an HR diagram are, for 10 points, what stars whose luminosity undergoes changes?
Examples of these objects found in the bottom-left corner of an HR diagram include DAV and ZZ Ceti.
variable stars [accept Cepheid variables or RR Lyrae before mentioned] 