Unukalhai
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Star Unukalhai (α serpentis) |
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| AladinLite | |||||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Snake | ||||||||||||||||||
| Right ascension | 15 h 44 m 16.08 s | ||||||||||||||||||
| declination | + 06 ° 25 ′ 32.3 ″ | ||||||||||||||||||
| Apparent brightness | 2.63 likes | ||||||||||||||||||
| Typing | |||||||||||||||||||
| B − V color index | +1.17 | ||||||||||||||||||
| U − B color index | +1.24 | ||||||||||||||||||
| R − I index | +0.56 | ||||||||||||||||||
| Spectral class | K2 III | ||||||||||||||||||
| Astrometry | |||||||||||||||||||
| Radial velocity | (+2.9 ± 0.4) km / s | ||||||||||||||||||
| parallax | (44.10 ± 0.19) mas | ||||||||||||||||||
| distance | (74.0 ± 0.3) ly (22.7 ± 0.1) pc |
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| Visual absolute brightness M vis | +0.85 mag | ||||||||||||||||||
| Proper movement | |||||||||||||||||||
| Rec. Share: | (133.84 ± 0.21) mas / a | ||||||||||||||||||
| Dec. portion: | (44.81 ± 0.19) mas / a | ||||||||||||||||||
| Physical Properties | |||||||||||||||||||
| Luminosity |
70 L ☉ |
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| Effective temperature | 4300 K | ||||||||||||||||||
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Other names and catalog entries |
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Unukalhai (also Unuk ), Bayer name α Serpentis ( Alpha Serpentis , α Ser for short ), is a triple star in the constellation Snake, about 70 light years away . The name Unuk is an abbreviation of Unukalhai ( Unuk Al-Haia ) and means something like neck of the serpent عنق الحية / ʿUnuqu ʾl-ḥayya . α Serpentis is also called Cor Serpentis ( Latin heart of the snake ).
The main component α Serpentis A is of the spectral type K2 III and has an apparent magnitude of +2.6 mag. It has 70 times the brightness at a surface temperature of 4300 Kelvin and 15 times the radius of the sun.
58 arc seconds away is α Serpentis B (spectral type A3) with an apparent brightness of 11.8 mag; α Serpentis C, a 13th magnitude star, is 2.3 arc minutes from A.