BL Herculis
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Star BL Herculis |
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| AladinLite | |||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | Hercules | ||||||||||
| Right ascension | 18 h 01 m 9.22 s | ||||||||||
| declination | + 19 ° 14 ′ 56.7 ″ | ||||||||||
| Apparent brightness | 9.7 mag 9.7 to 10.62 mag |
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| Typing | |||||||||||
| B − V color index | +0.84 | ||||||||||
| Spectral class | F0-F6 II-III | ||||||||||
| Variable star type | CWB | ||||||||||
| Astrometry | |||||||||||
| Radial velocity | +18.0 km / s | ||||||||||
| parallax | (0.79 ± 0.03) mas | ||||||||||
| distance | (4130 ± 150) ly 1,260 pc |
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| Proper movement | |||||||||||
| Rec. Share: | (−4.14 ± 0.04) mas / a | ||||||||||
| Dec. portion: | (−11.75 ± 0.06) mas / a | ||||||||||
| Physical Properties | |||||||||||
| Dimensions | 0.75 M ☉ | ||||||||||
| radius | 8.5 R ☉ | ||||||||||
| Metallicity [Fe / H] | (−0.1) | ||||||||||
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Other names and catalog entries |
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BL Herculis is a star about 4500 light years away . It is the prototype of the BL Herculis stars ( Type II Cepheids ), which belong to the pulsation-variable stars .
BL Herculis shows during a period of 1.3 days a fluctuation of the magnitude from about 9.7 at the maximum to 10.6 at the minimum.
See also
Web links
Individual evidence
- ↑ a b c d e f BL Her. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed September 15, 2018 .
- ↑ a b c d Aaron L. Alexander, Michael D. Joner, DH McNamara: A photometric study of BL Herculis . In: The Astrophysical Society of the Pacific . 99, 1987, pp. 645-653. doi : 10.1086 / 132028 .
- ↑ a b c BL Her. In: VSX. AAVSO, accessed September 15, 2018 .
- ↑ Thomas Maas, Sunetra Giridhar, David L. Lambert: The Chemical Compositions of the Type II Cepheids-The BL Herculis and W Virginis Variables . In: The Astrophysical Journal . 666, 2007, p. 378. arxiv : 0706.2029 . bibcode : 2007ApJ ... 666..378M . doi : 10.1086 / 520081 .