Adara
HIP 33579; Epsilon CMa; 21 CMa
천체 데이터
- 카탈로그 지정명
- HIP 33579; Epsilon CMa; 21 CMa
- 유형
- DoubleStar
- 별자리
- CMa
- 등급
- 1.50
- 적경
- 06h 58m 37.5s
- 적위
- -28° 58' 20.0"
- 거리
- 405 광년
- HR
- 2618
- HIP
- 33579
- Bayer
- Epsilon
서베이 이미지
서베이 이미지 로드 중…
Adara 소개
설명
Adara (Epsilon Canis Majoris) is the second brightest star in Canis Major at magnitude 1.50, located about 430 light-years from Earth. It is a blue giant of spectral type B2Iab, about 11 times the mass of the Sun and roughly 38,000 times more luminous. Adara is one of the strongest sources of extreme ultraviolet radiation in the sky as seen from Earth.
관측 팁
Adara sits at the hindquarters of Canis Major, forming part of the distinctive triangle of stars south of Sirius. Its blue-white color is evident through binoculars. Adara has a faint companion (magnitude 7.5) at about 7.5 arcseconds separation, resolvable in a small telescope. The star is visible from both hemispheres. Best observed from January through March.
역사
The name Adara comes from the Arabic 'al-Adhara' meaning 'the maidens' or 'the virgins.' About 4.7 million years ago, Adara was the brightest star in Earth's sky, shining at magnitude -3.99 when it was only about 34 light-years away. Since then, its proper motion has carried it much farther from the Sun.
재미있는 사실
Adara was once the brightest star in Earth's sky — it holds the record for the brightest apparent magnitude ever achieved by any star other than the Sun as seen from Earth's position, reaching nearly magnitude -4 about 4.7 million years ago. It is the strongest source of photons in the extreme ultraviolet range (504-912 Å) in the sky.