what is the anomalous in this variation?
A group of pulsating stars on the instability strip have periods of less than 2 days, but with higher luminosities.
Cepheid variable
A group of pulsating stars on the instability strip have periods of less than 2 days, similar to RR Lyrae variables but with higher luminosities. 
do all stars spend the same amount of time on the main sequence The total life span can be estimated, to first approximation, as the total energy produced divided by the star's luminosity. what is main sequence? Continuous and distinctive band of stars that appears on plots of stellar color versus brightness. describe a few of its properties? Majority of stars on a typical HR diagram lie along the main-sequence curve and temperature of a star determines its spectral type mention a few variations in luminosity color? Cepheid variables, Delta Scuti variables, and Beta Cephei variables what is the first variation? A type of star that pulsates radially, varying in both diameter and temperature name a few stars from such variation? UNANSWERABLE
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Cepheid variable [SEP] Anomalous Cepheids
A group of pulsating stars on the instability strip have periods of less than 2 days, similar to RR Lyrae variables but with higher luminosities. Anomalous Cepheid variables have masses higher than type II Cepheids, RR Lyrae variables, and our sun. It is unclear whether they are young stars on a "turned-back" horizontal branch, blue stragglers formed through mass transfer in binary systems, or a mix of both.