W Orionis is a
carbon star
A carbon star (C-type star) is typically an asymptotic giant branch star, a luminous 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 mos ...
in the
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
Orion, approximately away. It varies regularly in brightness between extremes of
magnitude 4.4 and 6.9 roughly every 7 months.
Variability
W Orionis is a
semiregular variable with an approximately 212‑day cycle.
[ A long secondary period of 2,450 days has also been reported.][
]
Properties
The angular diameter of W Orionis has been measured using interferometry
Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...
and a value of 9.7 mas
Mas, Más or MAS may refer to:
Film and TV
* Más y Menos, fictional superhero characters, from the Teen Titans animated television series
* Más (Breaking Bad), "Más" (''Breaking Bad''), a season three episode of ''Breaking Bad''
Songs
* Más ( ...
is found. Although it is known to be a pulsating variable star, no changes in the diameter were seen.[
Technetium has not been detected in W Orionis, an unexpected result since this ]s-process
The slow neutron-capture process, or ''s''-process, is a series of reactions in nuclear astrophysics that occur in stars, particularly asymptotic giant branch stars. The ''s''-process is responsible for the creation (nucleosynthesis) of approximat ...
element should be dredged up in all thermally-pulsating AGB stars and especially in carbon stars.[
]
References
External links
W Orionis
Kaler's Stars
{{DEFAULTSORT:W Orionis
Orion (constellation)
Orionis, W
032736
023680
Durchmusterung objects
Semiregular variable stars
Carbon stars