Cetus


Cetus


English nameWhale

Major
major
alpha CetiMenkarmagn. 2,8RA: 03h 02m 16.78sDec: +04 05' 23.1"
beta CetiDeneb Kaitosmagn. 2,2RA: 00h 43m 35.35sDec: -17 59' 11.9"
omicron CetiMiramagn. 2,0RA: 02h 19m 20.73sDec: -02 58' 38.9"

DescriptionThe constellation of Cetus is crossed in the northern part by equator: it is to the south of ecliptic, under the zodiacal constellations Aries and Pisces.

Though very wide, it hasn't any particular heavenly objects besides a red pulsating star called Mira, that is "marvelous". Mira is an enormous body, with a diameter of 550 millions kilometers, but with a very low superficial temperature (1.900K): thanks to this temperature in its outer zones there are molecular compounds such as oxide of titanium and water vapor, which darken the star light, making it much less bright than the Sun. But periodically the temperature goes up to 2.700K, the vapors dissolved and Mira gradually becomes more bright up to 80 times more shining than the Sun; then the temperature returns to decrease, the vapors reformed and brightness returns to very low levels. This cycle lasts about 331 days. We know about 4500 stars which are similar to Mira.


Mythology
and history
The constellation of Cetus has traditionally represented the sea monster sent by Poseidon to devastate Cepheus' and Cassiopeia's country. To be placated, it had to receive in sacrifice Andromeda, but while it was preparing to devour the young girl it was petrified by Perseus with Medusa's head.


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