V Hydrae
Encyclopedia
V Hydrae is a variable star in the constellation
Hydra
. It is considered by astronomers to be a carbon star
. With a B-V colour index of +5.5 it is one of the reddest stars visible. It has a period of approximately 18 years and a sub-period of approximately 530 days.
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....
Hydra
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...
. It is considered by astronomers to be a carbon star
Carbon star
A carbon star is a late-type star similar to a red giant whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds,...
. With a B-V colour index of +5.5 it is one of the reddest stars visible. It has a period of approximately 18 years and a sub-period of approximately 530 days.