Binary star system in the constellation Hydra
Psi Hydrae (ψ Hydrae ) is astar system in the equatorialconstellation ofHydra . Based upon an annualparallax shift of 14.09 mas as seen from Earth, it is located around 231 light years away from theSun . It is faintly visible to the naked eye with anapparent magnitude of 4.97.[ 2]
This is a probableastrometric binary system.[ 9] evolved giant star with astellar classification of K0 III.[ 3] red clump star that is generating energy through the fusion of helium at its core.[ 10] angular diameter is± 0.02 mas [ 11] radius of the Sun .[ 6] [ 7] solar luminosity from itsphotosphere at aneffective temperature of 4,680. K.[ 5]
Cultural significance [ edit ] TheKalapalo people ofMato Grosso state in Brazil called this star andβ Hya Kafanifani .[ 12]
^a b c d e 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 . ^a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)",Catalogue of Eggen's UBV Data ,SIMBAD ,Bibcode :1986EgUBV........0M . ^a b Houk, Nancy; Smith-Moore, M. (1978),Michigan catalogue of two-dimensional spectral types for the HD stars , vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan,Bibcode :1988mcts.book.....H . ^ 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. ^a b c d e McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants",Astrophysical Journal Supplement Series ,74 :1075– 1128,Bibcode :1990ApJS...74.1075M ,doi :10.1086/191527 ^a b Lang, Kenneth R. (2006),Astrophysical formulae Birkhäuser ,ISBN 3-540-29692-1 * ) is given by:2 ⋅ R ∗ = ( 71.0 ⋅ 1.39 ⋅ 10 − 3 ) AU 0.0046491 AU / R ⨀ ≈ 21.2 ⋅ R ⨀ {\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(71.0\cdot 1.39\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 21.2\cdot R_{\bigodot }\end{aligned}}} ^a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars",Monthly Notices of the Royal Astronomical Society ,427 (1):343– 57,arXiv :1208.2037 Bibcode :2012MNRAS.427..343M ,doi :10.1111/j.1365-2966.2012.21873.x S2CID 118665352 . ^ "* psi Hya" .SIMBAD Centre de données astronomiques de Strasbourg . Retrieved2017-03-17 .{{cite web }}: CS1 maint: postscript (link )^ Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion",The Astronomical Journal ,129 (5):2420– 2427,Bibcode :2005AJ....129.2420M ,doi :10.1086/429590 ^ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity",The Astrophysical Journal ,539 (2):732– 741,arXiv :astro-ph/0003329 Bibcode :2000ApJ...539..732A ,doi :10.1086/309278 ,S2CID 16673121 . ^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements",Astronomy and Astrophysics ,431 (2):773– 777,Bibcode :2005A&A...431..773R ,doi :10.1051/0004-6361:20042039 ^ Basso, Ellen B. (1987).In Favor of Deceit: A Study of Tricksters in an Amazonian Society 360 .ISBN 0-8165-1022-9
