Astronomy:Xi Hydrae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h 33m 00.11505s[1] |
| Declination | −31° 51′ 27.4435″[1] |
| Apparent magnitude (V) | 3.54[2] |
| Characteristics | |
| Spectral type | G7 III[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.90±0.30[3] km/s |
| Proper motion (μ) | RA: −209.62[1] mas/yr Dec.: −40.84[1] mas/yr |
| Parallax (π) | 25.16 ± 0.16[1] mas |
| Distance | 129.6 ± 0.8 ly (39.7 ± 0.3 pc) |
| Absolute magnitude (MV) | +0.54[4] |
| Details | |
| Mass | 2.94±0.15[5] M☉ |
| Radius | 10.2±0.1[6] R☉ |
| Luminosity | 57.65±2.39[6] L☉ |
| Surface gravity (log g) | 2.87±0.02[5] cgs |
| Temperature | 5,044±40[5] K |
| Metallicity [Fe/H] | +0.16±0.20[5] dex |
| Rotational velocity (v sin i) | 2.7[6] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Xi Hydrae, Latinised from ξ Hydrae, is a solitary[9] star in the equatorial constellation of Hydra. It was also given the Flamsteed designation 19 Crateris. This magnitude 3.54[2] star is situated 130 light-years from Earth and has a radius about 10 times that of the Sun. It is radiating 58 times as much luminosity as the Sun.[6]
Flamsteed gave Xi Hydrae the designation 19 Crateris. He included a number of stars now within the IAU boundaries of Hydra as part of a Hydra & Crater constellation overlapping parts of both modern constellations.[10]
The star Xi Hydrae is particularly interesting in the field of asteroseismology since it shows solar-like oscillations. Multiple frequency oscillations are found with periods between 2.0 and 5.5 hours.[11]
Xi Hydrae has left the main sequence, having exhausted the supply of hydrogen in its core. Its spectrum is that of a red giant. Modelling its physical properties against theoretical evolutionary tracks shows that it has just reached the foot of the red giant branch for a star with an initial mass around 3 M☉. This puts its age at about 510 myr.[12]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics 352: 495–507, Bibcode: 1999A&A...352..495M.
- ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 5.0 5.1 5.2 5.3 Heiter, U.; Jofré, P.; Gustafsson, B.; Korn, A. J.; Soubiran, C.; Thévenin, F. (2015), "Gaia FGK benchmark stars: Effective temperatures and surface gravities", Astronomy & Astrophysics 582: A49, doi:10.1051/0004-6361/201526319, Bibcode: 2015A&A...582A..49H.
- ↑ 6.0 6.1 6.2 6.3 Bruntt, H. et al. (July 2010), "Accurate fundamental parameters for 23 bright solar-type stars", Monthly Notices of the Royal Astronomical Society 405 (3): 1907–1923, doi:10.1111/j.1365-2966.2010.16575.x, Bibcode: 2010MNRAS.405.1907B.
- ↑ "URANOMETRIA ARGENTINA". http://www.uranometriaargentina.com/.
- ↑ "ksi Hya". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ksi+Hya.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Wagman, M. (August 1987), "Flamsteed's Missing Stars", Journal for the History of Astronomy 18 (3): 216, doi:10.1177/002182868701800305, Bibcode: 1987JHA....18..209W.
- ↑ Frandsen, S.; Carrier, F.; Aerts, C.; Stello, D.; Maas, T.; Burnet, M.; Bruntt, H.; Teixeira, T. C. et al. (2002). "Detection of Solar-like oscillations in the G7 giant star ξ Hya". Astronomy and Astrophysics 394: L5–L8. doi:10.1051/0004-6361:20021281. Bibcode: 2002A&A...394L...5F.
- ↑ Thévenin, F.; Kervella, P.; Pichon, B.; Morel, P.; Di Folco, E.; Lebreton, Y. (2005). "VLTI/VINCI diameter constraints on the evolutionary status of δ Eri, ξ Hya, η Boo". Astronomy and Astrophysics 436 (1): 253. doi:10.1051/0004-6361:20042075. Bibcode: 2005A&A...436..253T.
External links
- Wisky.org Star Catalogue
- ESO Article: The Ultrabass Sounds of the Giant Star Xi Hya.
- Listen to Xi Hya (wav).
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