Pleione (star)
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Star Pleione |
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| Left in the Pleiades: Pleione | |||||||||||||||||||
| AladinLite | |||||||||||||||||||
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Observation dates equinox : J2000.0 , epoch : J2000.0 |
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| Constellation | bull | ||||||||||||||||||
| Right ascension | 03 h 49 m 11.22 s | ||||||||||||||||||
| declination | + 24 ° 08 ′ 12.2 ″ | ||||||||||||||||||
| Apparent brightness | 5.09 (4.83 to 5.38) mag | ||||||||||||||||||
| Typing | |||||||||||||||||||
| B − V color index | (−0.08) | ||||||||||||||||||
| U − B color index | (−0.28) | ||||||||||||||||||
| Spectral class | B8 Vne | ||||||||||||||||||
| Variable star type | Yes | ||||||||||||||||||
| Astrometry | |||||||||||||||||||
| Radial velocity | (5.1 ± 0.2) km / s | ||||||||||||||||||
| parallax | (7.72 ± 0.20) mas | ||||||||||||||||||
| distance | (422 ± 11) ly (129 ± 3) pc |
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| Proper movement | |||||||||||||||||||
| Rec. Share: | (18,638 ± 0.487) mas / a | ||||||||||||||||||
| Dec. portion: | (−48,678 ± 0.334) mas / a | ||||||||||||||||||
| Physical Properties | |||||||||||||||||||
| Dimensions | (3.6 ± 0.2) M ☉ | ||||||||||||||||||
| radius | (4.17 ± 0.17) R ☉ | ||||||||||||||||||
| Effective temperature | (12100 ± 280) K. | ||||||||||||||||||
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Other names and catalog entries |
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The star Pleione is a member of the Pleiades star cluster in the constellation Taurus . In addition to its proper name , it also bears the designations 28 Tauri and the variable designation BU Tauri.
The star is named after Pleione , the mother of the Pleiades in Greek mythology .
properties
Pleione is one of the bizarre of the known stars in the Milky Way : it rotates so fast that the star shape is no longer spherical, but flattened like a disc. In the equatorial region they are matter in the form of a plasma disk ( decretion disk ab). It is so hot that about half of the radiation from this star is generated by the disk, not by the star. There is evidence of a precession of the disk axis, possibly caused by a companion star. A smaller companion star and a protoplanetary disk are suspected.
According to the preliminary measurement results of the space probe Gaia, Pleione is at a distance of about 422 light years from Earth, while the Hipparcos mission found the star to be 382 light years away. It is a variable Be star that changes its brightness at irregular intervals between 4.83 m and 5.38 m .
Web links
- Pleione in Jim Kaler's star catalog
Individual evidence
- ↑ a b c d e Gaia data release 2 ( Gaia DR2 ), April 2018
- ↑ a b c d e eta Tau. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed July 22, 2018 .
- ↑ a b BU Tau. In: VSX. AAVSO, accessed July 22, 2018 .
- ↑ J. Zorec, Y. Fremat, L. Cidale: On the evolutionary status of Be stars. I. Field Be stars near the Sun . In: Astronomy and Astrophysics . 441, 2005, p. 235. arxiv : astro-ph / 0509119 . bibcode : 2005A & A ... 441..235Z . doi : 10.1051 / 0004-6361: 20053051 .
- ↑ a b TR White, BJS Pope, V. Antoci, PI Pápics, C. Aerts, DR Gies, K. Gordon, D. Huber, GH Schaefer, S. Aigrain, S. Albrecht, T. Barclay, G. Barentsen, PG Beck, TR Bedding, M. Fredslund Andersen, F. Grundahl, SB Howell, MJ Ireland, SJ Murphy, MB Nielsen, V. Silva Aguirre, PG Tuthill: Beyond the Kepler / K2 bright limit: Variability in the seven brightest members of the Pleiades . In: Monthly Notices of the Royal Astronomical Society . 471, No. 3, 2017, pp. 2882–2901. arxiv : 1708.07462 . bibcode : 2017MNRAS.471.2882W . doi : 10.1093 / mnras / stx1050 .
- ^ Hipparcos, the New Reduction (van Leeuwen, 2007)