Other causes of valve disease include: 1  Deposits of calcium (calcification) in parts of the valve. 2  A floppy valve, which is a common cause of mild mitral valve regurgitation. 3  Some congenital heart problems. 4  Infection of the valve (infective endocarditis). 5  A complication of various uncommon diseases.
exists and is an alternate of . Castor is a variable star and also a quadruple star system, and has a spectral class of A1/A2 giving it a colour of white to white blue. Castor is a variable star and also a quadruple star system, and has a spectral class of A1/A2 giving it a colour of white to white blue. See link for more information.  <br /><br /> See link for more information. Castor is a variable star and also a quadruple star system, and has a spectral class of A1/A2 giving it a colour of white to white blue. <br /><br />
Pulsating variable stars are intrinsic variables as their variation in brightness is due to a physical change within the star. In the case of pulsating variables this is due to the periodic expansion and contraction of the surface layers of the stars.his in turn allows us to determine the distance to such stars and is discussed in more detail on the next page. As with non-pulsating variables, there are several types of pulsating stars and some of the key types are described briefly below.