astro.wikisort.org - Star

Search / Calendar

Tau1 Hydrae is a triple star[3] system in the equatorial constellation of Hydra. Based upon the annual parallax shift of the two visible components as seen from Earth,[1] they are located about 18 parsecs (59 ly) from the Sun. The system has a combined apparent visual magnitude of +4.59,[2] which is bright enough to be visible to the naked eye at night.

For other stars with this Bayer designation, see τ Hydrae.
Tau1 Hydrae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Hydra
Right ascension 09h 29m 08.89655s[1]
Declination −02° 46′ 08.2649″[1]
Apparent magnitude (V) +4.59 (4.60 + 7.15)[2]
Characteristics
Spectral type F6 V + ? + K0[3]
B−V color index +0.411±0.015[2]
Astrometry
Radial velocity (Rv)+10.85±0.28[4] km/s
Absolute magnitude (MV)+3.28[5]
τ1 Hydrae A
Proper motion (μ) RA: +107.115[6] mas/yr
Dec.: −29.652[6] mas/yr
Parallax (π)56.2938 ± 0.5309 mas[6]
Distance57.9 ± 0.5 ly
(17.8 ± 0.2 pc)
τ1 Hydrae B
Proper motion (μ) RA: +138.487[7] mas/yr
Dec.: −17.371[7] mas/yr
Parallax (π)55.3675 ± 0.0638 mas[7]
Distance58.91 ± 0.07 ly
(18.06 ± 0.02 pc)
Orbit[8]
Period (P)2,807±23 d
Eccentricity (e)0.33±0.12
Periastron epoch (T)2445260 ± 150 JD
Semi-amplitude (K1)
(primary)		2.98±0.39 km/s
Details
τ1 Hydrae A
Mass1.20[9] M☉
Radius1.4[10] R☉
Luminosity (bolometric)3.369[2] L☉
Surface gravity (log g)4.12±0.14[9] cgs
Temperature6,473±220[9] K
Metallicity [Fe/H]−0.01[2] dex
Rotational velocity (v sin i)30.4±1.5[5] km/s
Age3.61[2] Gyr
τ1 Hydrae B
Mass0.86[11] M☉
Radius0.81[10] R☉
Luminosity0.435[7] L☉
Temperature5,197[7] K
Other designations
τ1 Hya, 31 Hydrae, BD−02°2901, GJ 348, HD 81997, HIP 46509, HR 3759, SAO 136895, WDS J09291-0246[12]
Database references
SIMBADτ1 Hya AB
τ1 Hya A
τ1 Hya B

The inner pair of stars form a single-lined spectroscopic binary with an orbital period of about 2,807 days and an eccentricity of 0.33.[8] The visible member of the pair, component A, is a visual magnitude 4.60[2] F-type main sequence star with a stellar classification of F6 V.[3] During the 1990s, it was thought to be a Gamma Doradus variable, but this was later discounted as it shows no short-term photometric variability. The star does show some long-term variability, possibly as a result of a magnetic activity cycle similar to the solar cycle.[13]

The tertiary member, component B, is a visual magnitude 7.15[2] K-type star with a class of K0.[3] It lies at a separation of 1,120 AU from the primary.[14] As of 2012, it was positioned at an angular separation of 67.5 arc seconds along a position angle of 4°.[15]


References


  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. Montesinos, B.; et al. (September 2016), "Incidence of debris discs around FGK stars in the solar neighbourhood", Astronomy & Astrophysics, 593: 31, arXiv:1605.05837, Bibcode:2016A&A...593A..51M, doi:10.1051/0004-6361/201628329, S2CID 55251562, A51.
  3. 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  4. 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  5. Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv:astro-ph/0509399, Bibcode:2006A&A...446..267R, doi:10.1051/0004-6361:20053911, S2CID 8642707
  6. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  7. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. Pourbaix, D.; et al. (September 2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy and Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  9. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  10. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  11. Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 14, arXiv:1401.6827, Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87, S2CID 56066740, 87.
  12. "tau01 Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-22.{{cite web}}: CS1 maint: postscript (link)
  13. Henry, G. W.; et al. (March 1999), "tau1 Hydrae: NOT A gamma DORADUS VARIABLE", Information Bulletin on Variable Stars, 4688 (4688): 1, Bibcode:1999IBVS.4688....1H.
  14. Allen, Peter R.; et al. (August 2012), "Low-mass Tertiary Companions to Spectroscopic Binaries. I. Common Proper Motion Survey for Wide Companions Using 2MASS", The Astronomical Journal, 144 (2): 12, arXiv:1206.4289, Bibcode:2012AJ....144...62A, doi:10.1088/0004-6256/144/2/62, S2CID 51051184, 62.
  15. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.

На других языках

- [en] Tau1 Hydrae

[es] Tau1 Hydrae

Tau1 Hydrae (τ1 Hydrae / 31 Hydrae / HD 81997)[1] es una estrella en la constelación de Hidra de magnitud aparente +4,60. Comparte la denominación de Bayer Tau con τ2 Hydrae, no existiendo relación física entre ambas estrellas. Ocasionalmente recibe el nombre de Ukdah Prima, «la primera (estrella) del nudo» —Ukdah proviene el árabe عقدة (uqdah), «nudo»—.

[ru] Тау 1 Гидры

Для того чтобы посмотреть другие звездные систем с этим обозначением Байера, см. Тау Гидры


Текст в блоке "Читать" взят с сайта "Википедия" и доступен по лицензии Creative Commons Attribution-ShareAlike; в отдельных случаях могут действовать дополнительные условия.

Другой контент может иметь иную лицензию. Перед использованием материалов сайта WikiSort.org внимательно изучите правила лицензирования конкретных элементов наполнения сайта.

2019-2025
WikiSort.org - проект по пересортировке и дополнению контента Википедии