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R Aquarii is a symbiotic star believed to contain a white dwarf and a Mira-type variable in a binary system. The orbital period is approximately 44 years. [5] The main Mira-type star is a red giant , and varies in brightness by a factor of several hundred and with a period of slightly more than a year; this variability was discovered ...
A star-forming region in the Large Magellanic Cloud. A star is a luminous spheroid of plasma held together by self-gravity. [citation needed] . The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night; their immense distances from Earth make them appear as fixed points of light.
Below are lists of the largest stars currently known, ordered by radius and separated into categories by galaxy. The unit of measurement used is the radius of the Sun (approximately 695,700 km; 432,300 mi).[1] The Sun, the orbit of Earth, Jupiter, and Neptune, compared to four stars. (Pistol Star, Rho Cassiopeiae, Betelgeuse, and VY Canis Majoris)
- Ob Associations
- T Associations
- R Associations
Young associations will contain 10–100 massive stars of spectral class O and B, and are known as OB associations. These are believed to form within the same small volume inside a giant molecular cloud. Once the surrounding dust and gas is blown away, the remaining stars become unbound and begin to drift apart.It is believed that the majority of all...
Young stellar groups can contain a number of infant T Tauri stars that are still in the process of entering the main sequence. These sparse populations of up to a thousand T Tauri stars are known as T associations. The nearest example is the Taurus-Auriga T association (Tau-Aur T association), located at a distance of 140 parsecs from the Sun. Othe...
Associations of stars that illuminate reflection nebulae are called R associations, a name suggested by Sidney van den Bergh after he discovered that the stars in these nebulae had a non-uniform distribution. These young stellar groupings contain main sequence stars that are not sufficiently massive to disperse the interstellar clouds in which they...
Rho Ophiuchi cloud complex. The Rho Ophiuchi cloud complex is a complex of interstellar clouds with different nebulae, particularly a dark nebula which is centered 1° south of the star ρ Ophiuchi, which it among others extends to, of the constellation Ophiuchus.
Proxima Centauri is a small, low-mass star located 4.2465 light-years (1.3020 pc) away from the Sun in the southern constellation of Centaurus. Its Latin name means the 'nearest [star] of Centaurus'. It was discovered in 1915 by Robert Innes and is the nearest-known star to the Sun. With a quiescent apparent magnitude of 11.13, it is too faint ...
Sirius is the brightest star in the night sky. Its name is derived from the Greek word Σείριος (Latin script: Seirios ), meaning lit. 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinized to Alpha Canis Majoris, and abbreviated α CMa or Alpha CMa.
