Monday, November 25, 2024

Delta Cephei Pulsates (all night)

On November evenings, the constellation of Cepheus culminates above Polaris in the northern sky. Its star Delta Cephei (or \EB Cep) is a giant, pulsating supergiant located about 900 light-years from our sun. Its variability occurs because it has consumed its core hydrogen, and it is entering old age. The
star varies in brightness by more than a factor of two every 5 days and 9 hours. At its peak, Delta shines as brightly as Zeta, the magnitude 3.35 star positioned 2.4 degrees to its west. At its minimum, it resembles magnitude 4.2 Epsilon, which is located 2.3 degrees to the southwest of Delta. By comparing those three stars, you can tell at a glance which part of its cycle the star
is in. Delta is also a nice double star when viewed in telescopes - splitting into a brighter yellow star and a dimmer blue star.

(Data courtesy of Starry Night)
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* Origin: CJ's Place, Orange City FL > cjsplace.thruhere.net (21:2/156)