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Alnair

HIP 109268; Alpha Gru

DoubleStar Gru 등급 1.74

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카탈로그 지정명
HIP 109268; Alpha Gru
유형
DoubleStar
별자리
Gru
등급
1.74
적경
22h 08m 14.0s
적위
-46° 57' 40.0"
거리
101 광년
HR
8425
HIP
109268
Bayer
Alpha
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Alnair 소개

설명

Alnair is the brightest star in the constellation Grus (the Crane) at magnitude 1.74, located about 101 light-years from Earth. It is a blue-white subgiant of spectral type B7IV, about 4 times the mass of the Sun and roughly 380 times more luminous. Alnair rotates rapidly, with a projected rotational velocity of about 215 km/s.

관측 팁

Alnair is a Southern Hemisphere star, visible from latitudes south of about 37°N. It marks the eye or beak of the Crane and helps identify the constellation Grus, which lies south of Fomalhaut. Together with the other bright stars of Grus, it forms a graceful pattern in the autumn/winter sky of the Southern Hemisphere. Best observed from September through November from southern latitudes.

역사

The name Alnair comes from the Arabic 'al-Nayyir' meaning 'the bright one,' originally referring to the brighter star in the tail of the Southern Fish. The constellation Grus was introduced by Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman in the late 16th century from observations made during voyages to the East Indies.

재미있는 사실

Alnair is a rapid rotator, spinning at over 200 km/s at its equator — about 100 times faster than the Sun. This rapid rotation likely gives it a noticeably oblate shape, though this has not yet been directly measured. It marks the transition point in our list between the 'first magnitude' stars (brighter than 1.5) and the slightly fainter members of the brightest star club.