Polaris is one of these stars, while another particularly noticeable one is Eta Aquilae, of unknown metallicity.
Polaris is one of these stars, while another particularly noticeable one is Eta Aquilae, of unknown metallicity. The assumption that metallicity does not affect them is essential to their usefulness. They are used as standard candles because of their consistent period-luminosity relationship; the former varies between three and thirty days, the latter between eight hundred and ten thousand solar. W Virginis stars are sometimes called the "type II" of these entities. FTP, identify this class of stars, named after the delta star of the constellation named for an ancient king.
Polaris is one of these stars, while another particularly noticeable one is Eta Aquilae, of unknown metallicity.
{Cepheid} variables