Alpha Cassiopeiae

Starbox begin
name=Alpha Cassiopeiae Starbox observe
epoch=J2000
ra=00^h 40^m 30.5^s
dec=+56° 32′ 14.5″
appmag_v=2.24
constell=Cassiopeia Starbox character
class=K0 IIIa
b-v=1.17
u-b=1.13
variable=Suspected Starbox astrometry
radial_v=−3.8
prop_mo_ra=50.36
prop_mo_dec=−32.17
parallax=14.27
p_error=0.57
absmag_v=−1.99 Starbox detail
mass=4–5
radius=42
luminosity=855 | temperature=4,530
metal=?
rotation=21 km/s
age=? Starbox catalog
names=18 Cassiopeiae, HR 168, BD+55°139, HD 3712, SAO 21609, FK5 21, HIP 3179, GC 792, ADS 561, CCDM J00405+5632

Alpha Cassiopeiae (α Cas / α Cassiopeiae ) is the second-brightest star in the constellation Cassiopeia (magnitude 2.25). It has the traditional name Schedar (which may also be spelt as "Shedar", "Shadar", "Schedir", or "Shedir").

It is an orange giant (spectral type K0 IIIa), a type of star cooler but much brighter than our Sun. In visible light only, it is well over 500 times brighter than the Sun. According to the "Hipparcos" astrometrical satellite, distance to the star is about 230 light years (or 70 parsecs).

Schedar has been sometimes classified as a variable star, but no variability has been detected since the 19th century. Also, three companions to the star have been listed in the Washington Double Star Catalog, but it seems that all of them are just line-of-sight optical components.

The name Schedar comes from the Arabic word صدر "şadr", "breast".

External links

* [http://www.astro.uiuc.edu/projects/sow/shedar.html Shedar] at Jim Kaler's Stars site
* [http://www.daviddarling.info/encyclopedia/S/Shedar.html Shedar (Alpha Cassiopeiae)]