Izar
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Double star Izar / ε Bootis |
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| AladinLite | ||||||||||||||||||||||||||||||||
| Constellation | Bear keeper | |||||||||||||||||||||||||||||||
| Right ascension | 14 h 44 m 59.2 s | |||||||||||||||||||||||||||||||
| declination | + 27 ° 04 ′ 27 ″ | |||||||||||||||||||||||||||||||
| Apparent brightness | 2.39 likes | |||||||||||||||||||||||||||||||
| Astrometry | ||||||||||||||||||||||||||||||||
| Radial velocity | (−16.31 ± 0.19) km / s | |||||||||||||||||||||||||||||||
| parallax | (16.1 ± 0.7) mas | |||||||||||||||||||||||||||||||
| distance | (200) ly (62 pc ) |
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| Proper movement : | ||||||||||||||||||||||||||||||||
| Rec. Share: | (−50.95 ± 0.59) mas / a | |||||||||||||||||||||||||||||||
| Dec. portion: | (21.07 ± 0.58) mas / a | |||||||||||||||||||||||||||||||
| Individual data | ||||||||||||||||||||||||||||||||
| Names | A; B. | |||||||||||||||||||||||||||||||
| Observation data: | ||||||||||||||||||||||||||||||||
| Apparent brightness | A. | (2.45) mag | ||||||||||||||||||||||||||||||
| B. | (4.80) likes | |||||||||||||||||||||||||||||||
| Typing: | ||||||||||||||||||||||||||||||||
| Spectral class | A. | K0 II-III | ||||||||||||||||||||||||||||||
| B. | A2 V | |||||||||||||||||||||||||||||||
| B − V color index | A. | (1.16) | ||||||||||||||||||||||||||||||
| B. | (0.05) | |||||||||||||||||||||||||||||||
| Other names and catalog entries |
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Izar ( Arabic إزار, DMG izār 'cape'), Bayer name Epsilon Bootis (abbreviated ε Boo ) also Pulcherrima (Latin: the most beautiful ), is the name of the second brightest star in the Bear Guardian constellation . It is 210 light years away from us.
Izar is a charming double star , consisting of an orange-red star with an apparent magnitude of 2.7 mag and a blue star with a magnitude of 5.1.
Because of the small distance of 2.8 " , combined with the large difference in brightness between the two components, a telescope with an opening of approx. 75 mm or more is required for separation ( position angle of the companion: 340 degrees). An eight-inch model already clearly shows the very different star colors and enables clearer Air also a daytime observation .
Other of its names are Mizar , Mirak and Mirach , which are also star names in the Big Dipper and Andromeda .
Star triangle
Izar is exactly in the center of gravity of an almost equilateral triangle with the bright stars Gemma (α in the crown), Arktur and Seginus (α and γ Bootis). It lies roughly in the extension of the drawbar of the Big Dipper (Alkaid, in the picture above right).
See also
Web links
Individual evidence
- ↑ a b c eps Boo. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on October 13, 2018 .
- ↑ a b c d eps Boo A. In: SIMBAD. Center de Données astronomiques de Strasbourg, accessed on October 13, 2018 .
- ↑ a b c d eps Boo B. In: SIMBAD. Center de Données astronomiques de Strasbourg, accessed on October 13, 2018 .