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 />
Best Answer: There is certain type of variable star that has a constant period and brilliance. When a star of that type is discovered the brightness of it in the telescope can be used to determine it's distance. The dimmer it appears the farther away it is.It has even been used to determine the distance to nearby galaxies. Source(s): A good memory and a lot of reading.hen a star of that type is discovered the brightness of it in the telescope can be used to determine it's distance. The dimmer it appears the farther away it is.