Grus (constellation)

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Grus
Constellation
Grus
List of stars in Grus
Abbreviation Grus
Genitive Gruis
Pronunciation /ˈɡrʌs/, or colloquially /ˈɡrs/; genitive /ˈɡrɨs/
Symbolism the Crane
Right ascension 22 h
Declination −47°
Quadrant SQ4
Area 366 sq. deg. (45th)
Main stars 7
Bayer/Flamsteed
stars
28
Stars with planets 5
Stars brighter than 3.00m 3
Stars within 10.00 pc (32.62 ly) 1
Brightest star α Gru (Alnair) (1.73m)
Nearest star Gliese 832
(16.11 ly, 4.94 pc)
Messier objects 0
Meteor showers ?????
?????
Bordering
constellations
Piscis Austrinus
Microscopium
Indus
Tucana
Phoenix
Sculptor

Visible at latitudes between +34° and −90°.
Best visible at 21:00 (9 p.m.) during the month of October.

Grus (pron.: /ˈɡrʌs/, or colloquially /ˈɡrs/) is a constellation in the southern sky. Its name is Latin for the crane, a species of bird. It was introduced in the late 16th century.

Contents

History [edit]

The stars that form Grus were originally considered part of Piscis Austrinus (the southern fish). The Arabic name of Gamma Gruis (al-dhanab, "the tail") reflects this origins.

The stars were first defined as a separate constellation by Petrus Plancius, who created twelve new constellations based on the observations of Pieter Dirkszoon Keyser and Frederick de Houtman.[1] Grus first appeared on a 35-cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with Jodocus Hondius. Its first depiction in a celestial atlas was in Johann Bayer's Uranometria of 1603.

An alternative name for the constellation, Phoenicopterus (Latin for flamingo), was used briefly during the early 17th century.[2]

Grus represents a crane, though it is sometimes seen as a flamingo. There are no ancient myths associated with Grus.[1]

Notable features [edit]

The constellation Grus as it can be seen by the naked eye.

Stars [edit]

Grus has several bright stars. Alpha Gruis, called Alnair, is a blue-white star of magnitude 1.7, 101 light-years from Earth. Its traditional name, Alnair, means "the bright one" and refers to its status as the brightest star in Grus. Beta Gruis is a red giant variable star with a minimum magnitude of 2.3 and a maximum magnitude of 2.0; it is 170 light-years from Earth. Gamma Gruis is a blue giant of magnitude 3.0, 203 light-years from Earth.[1]

There are several celebrated naked-eye double stars in Grus. Delta Gruis, composed of Delta1 Gruis and Delta2 Gruis, is an optical double. Delta1 is a yellow giant of magnitude 4.0, 296 light-years from Earth, and Delta2 is a red giant of magnitude 4.1, 325 light-years from Earth. Mu Gruis, composed of Mu1 Gruis and Mu2 Gruis, is also an optical double. Mu1 is the brighter of the two at magnitude 4.8 - it is 262 light-years from Earth - and Mu2 the dimmer at magnitude 5.is 240 light-years from Earth. Pi Gruis, an optical double with a variable component, is composed of Pi1 Gruis and Pi2. Pi1 is a semi-regular red giant with a minimum magnitude of 6.7 and a maximum magnitude of 5.4. It has a period of 150 days and is 500 light-years from Earth. Pi2 is a white giant 132 light-years from Earth and is often brighter than its companion at magnitude 5.6.[1]

Equivalents [edit]

The stars that correspond to Grus cannot all be seen from China. In Chinese astronomy some of them are located in the Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ), while the rest were placed among the Southern Asterisms (近南極星區, Jìnnánjíxīngōu) by Xu Guangqi, based on knowledge of western star charts.

See also [edit]

References [edit]

External links [edit]


Coordinates: Sky map 22h 00m 00s, −47° 00′ 00″