by Bill Pellerin, GuideStar editor
Object: Caph-Beta CasClass: Delta Scuti variable star
Magnitude: 2.25
R.A.: 00 h, 9 m, 11 s
Dec: 59 degrees, 08 minutes, 59 seconds
Distance: 55 ly
Constellation: Cassopeia
Spectral: F2
Optics needed: Unaided Eye
Why this object is interesting:
Beta Cas is an old star and like many old stars it is starting to show its age by becoming variable. In the categories of variable stars this one is called a Delta Scuti variable star and it has some common characteristics with Cepheid variable stars. Cepheids are famous because their intrinsic luminosity (power output) is related to their period of variability. Thus, they and the Delta Scuti variable stars allow astronomers to measure the distance to stars and star systems.
If you know the intrinsic brightness of a star it’s easy to determine the distance using the inverse square law. That is, the brightness we see is inversely proportional to the square of the distance.
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