Facts About Mimosa the Star in Crux

Crux, also known as the Southern Cross, is a constellation in the Southern Hemisphere. Mimosa (Beta Crucis) is the second-brightest star in the constellation and forms the left point of the cross.

Brightness

• According to the Abrams Planetarium, Mimosa is the 20th brightest star as seen from the Earth at night. The star has an apparent magnitude of 1.25 and an absolute magnitude of -3.92.

Classification

• Mimosa is classified a blue-white, giant star with a temperature that reaches almost 27,000 degrees Kelvin. However, Jim Kaler, Professor Emeritus of Astronomy, writes that the temperature and luminosity of Mimosa indicate a mass of 14 times that of the Earth's sun. He further writes that this fact clearly shows that the star is not a giant but is a dwarf star that is approximately halfway through its 11-million-year hydrogen-fusing lifetime. Kaler notes that such misclassification is not uncommon.

Type and Distance

• According to the Encyclopedia Britannica, Mimosa is a binary of two B-type stars about 350 light-years from Earth. Other sources estimate the distance differently.