Circinus was first defined in 1756 by the French astronomer Nicolas-Louis de Lacaille. Its name is Latin for compass, referring to the drafting tool used for drawing circles. The Milky Way runs through the constellation, featuring prominent objects such as the open cluster NGC 5823 and the planetary nebula NGC 5315.
About Circinus in brief
Circinus was first defined in 1756 by the French astronomer Nicolas-Louis de Lacaille. Its name is Latin for compass, referring to the drafting tool used for drawing circles. Its brightest star is Alpha Circini, with an apparent magnitude of 3. 19. The Milky Way runs through the constellation, featuring prominent objects such as the open cluster NGC 5823 and the planetary nebula NGC 5315. Circinus hosts a notable spiral galaxy, the Circinus Galaxy, discovered in 1977; it is the closest Seyfert galaxy to the Milky Way. Supernova SN 185 appeared in Circinus in 185 AD and was recorded by Chinese observers. Two sun-like stars have planetary systems: HD 134060 has two small planets, and HD 129445 has a Jupiter-like planet. The official constellation boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a polygon of 14 segments. The right ascension coordinates of these borders lie between 13h 38. 4m and 15h 30. 2m, and the declination coordinates are between −55. 43° and −70. 62°.circinus culminates each year at 9 p. m. on 30 July. The recommended three-letter abbreviation for the constellation,.
as adopted by the International Astronomical Union in 1922, is “Cir”. Circinus is a faint constellation, with only one star brighter than fourth magnitude. It lies adjacent to the Alpha and Beta Centauri stars. As it is at declination −50° to −70°, the whole constellation is only visible south of latitude 30° N. It has around 1.8 times the diameter of the Sun, as they are a 150-mm arc of a common centre of gravity. The brighter star in the constellation is a bluish Be star of spectral type B5IV+ and magnitude 4.5+. Both are blue stars of spectral types O7-VIII-V9, and have around 9 days to orbit each other every 180 years. The second brighter star is Betacircini, a white main sequence star with a magnitude of 4. 07, about 100 light-years away. It is a close eclipsing binary star, with a close eclipse every 9 days, and an estimated 5V to 5V, respectively. Alphacircini forms a binary star system with an orange dwarf companion, which with a separation of 5. 7arcseconds is only discernible with a telescope.
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This page is based on the article Circinus published in Wikipedia (as of Nov. 04, 2020) and was automatically summarized using artificial intelligence.
