S Monocerotis
Encyclopedia
S Monocerotis, also known as 15 Monocerotis, is a massive variable star system located in the constellation
Monoceros
. It is a spectroscopic binary system with an orbital
period of 25 years. It is a type O giant with a stellar classification
of O7Ve, and is about 8,500 times as luminous as the Sun, which varies in between magnitude 4.2 and 4.6. The star lies at the base of the Christmas Tree Cluster in NGC 2264
.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Monoceros
Monoceros
Monoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east...
. It is a spectroscopic binary system with an orbital
period of 25 years. It is a type O giant with a stellar classification
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
of O7Ve, and is about 8,500 times as luminous as the Sun, which varies in between magnitude 4.2 and 4.6. The star lies at the base of the Christmas Tree Cluster in NGC 2264
NGC 2264
NGC 2264 is the designation number of the New General Catalogue that identifies two astronomical objects as a single object:*the Cone Nebula,*the Christmas Tree Cluster,Two other objects are within this designation but not officially included:...
.