Binary star system in the constellation Hydra
Theta Hydrae , Latinized from θ Hydrae , is a binary star [ 8] constellation Hydra . It is visible to the naked eye with an apparent visual magnitude of 3.9.[ 2] proper motion [ 8] parallax shift of mas [ 1] light years double with a magnitude 9.9 star located at an angular separation of arcseconds [ 10]
The primary component of this system is a B-type main sequence star with a stellar classification of B9.5 V.[ 3] Lambda Boötis star , indicating it displays an underabundance of iron peak elements.[ 11] peculiar B star .[ 12]
An orbiting white dwarf companion was discovered in 1998 from its X-ray emission . This degenerate star must have evolved from a progenitor that was once more massive than the current primary.[ 8] [ 8] mass of the Sun , whereas Holberg et al. (2013) put it as high as 1.21[ 3] [ 13]
References
^ a b c d e f 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 .^ a b c d Cousins, A. W. J. (1984), "Standardization of Broadband Photometry of Equatorial Standards", South African Astronomical Observatory Circulars , 8 : 59, Bibcode :1984SAAOC...8...59C . ^ a b c d e f Holberg, J. B.; et al. (November 2013), "Where are all the Sirius-like binary systems?", Monthly Notices of the Royal Astronomical Society , 435 (3): 2077– 2091, arXiv :1307.8047 Bibcode :2013MNRAS.435.2077H , doi :10.1093/mnras/stt1433 ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system", Astronomy Letters , 32 (11): 759– 771, arXiv :1606.08053 Bibcode :2006AstL...32..759G , doi :10.1134/S1063773706110065 , S2CID 119231169 . ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters , 38 (5): 331, arXiv :1108.4971 Bibcode :2012AstL...38..331A , doi :10.1134/S1063773712050015 , S2CID 119257644 . ^ a b c Wu, Yue; et al. (January 2011), "Coudé-feed stellar spectral library – atmospheric parameters", Astronomy and Astrophysics , 525 : A71, arXiv :1009.1491 Bibcode :2011A&A...525A..71W , doi :10.1051/0004-6361/201015014 , S2CID 53480665 . ^ Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics , 537 : A120, arXiv :1201.2052 Bibcode :2012A&A...537A.120Z , doi :10.1051/0004-6361/201117691 , S2CID 55586789 . ^ a b c d e Burleigh, M. R.; Barstow, M. A. (January 1999), "Theta Hya: spectroscopic identification of a second B star+white dwarf binary", Astronomy and Astrophysics , 341 : 795– 798, arXiv :astro-ph/9810113 Bibcode :1999A&A...341..795B . ^ "tet Hya" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 2017-01-04 .{{cite web }}: CS1 maint: postscript (link )^ Privett, Grant; Jones, Kevin (2013), The Constellation Observing Atlas Bibcode :2013coa..book.....P , ISBN 978-1461476481 ^ King, J. R. (July 1994), "Accretion from Circumstellar Discs and the Lambda-Bootis Phenomenon" , Monthly Notices of the Royal Astronomical Society 269 (1): 209– 217, Bibcode :1994MNRAS.269..209K , doi :10.1093/mnras/269.1.209 ^ Baschek, Bodo; Searle, Leonard (February 1969), "The Chemical Composition of the Lambda Bootis Stars", Astrophysical Journal , 155 : 537, Bibcode :1969ApJ...155..537B , doi :10.1086/149890 ^ Vennes, S.; Kawka, A. (September 2008), "On the empirical evidence for the existence of ultramassive white dwarfs", Monthly Notices of the Royal Astronomical Society , 389 (3): 1367– 1374, arXiv :0806.4742 Bibcode :2008MNRAS.389.1367V , doi :10.1111/j.1365-2966.2008.13652.x S2CID 15349194 .
External links
Kaler, James B. (May 8, 2015), "Theta Hydrae" , Stars , University of Illinois, retrieved 2016-01-04 .
Information related to Theta Hydrae
