Caph (Beta Cassiopeiae)


Caph (Beta Cassiopeiae) is a giant or subgiant F star that is the second brightest star in the constellation Cassiopeia. Its name comes from an Arabic phrase meaning "the stained hand" – the W-shape of this constellation being interpreted in Arab lore as the splayed fingers of a stretched hand that has been colored by henna.


In terms of its evolution, Caph is currently in the Hertzsprung Gap, a relatively short-lived stage (lasting a few tens of millions of years), in which its core will shrink while its outer layers expand to become a red giant. It is also unusual in being a Delta Scuti star – in fact, the brightest of this type – varying in brightness by about 6% over a 2.5-hour period. It has a small companion, about which little is known, in a 27-day orbit.

visual magnitude 2.28 (2.252.31)
absolute magnitude +1.16
spectral type F2 III-IV
surface temperature 6,700 K
luminosity (Sun=1) 28
radius (Sun=1) 4
mass (Sun=1) 2
distance 47 4 light-years (14 1 pc)
Position R.A. 00h 09m 10.7s,
Dec. +59 08' 59"
Other designations Kaff, Al Sanam al Nakah, Gl 8,
HR 21, BD+583, HD 432,
LHS 1027, GCTP 16.00, SAO 21133,
FK5 2, HIP 746, GC 147, ADS 107,
CCDM J00092+5909