Binary star system in the constellation Pyxis
Delta Pyxidis (δ Pyxidis ) is binary star [ 9] system in southern constellation of Pyxis . Having an apparent visual magnitude of +4.877,[ 2] it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 13.19 mas as seen from Earth,[ 1] it is located around 250 light years from the Sun.
In Chinese , 天狗 (Tiān Gǒu ), meaning Celestial Dog , refers to an asterism consisting of δ Pyxidis, e Velorum , f Velorum , β Pyxidis , α Pyxidis and γ Pyxidis . Consequently, δ Pyxidis itself is known as 天狗七 (Tiān Gǒu qī , English: the Seventh Star of Celestial Dog .)[ 10]
This is an astrometric binary system, as determined by changes in the proper motion of the primary.[ 11] The visible component has a stellar classification of A3 IV,[ 3] indicating it has the spectrum of an A-type subgiant star that is consuming the last of the hydrogen at its core. At the age of around 296 million years,[ 6] it is 92.5%[ 3] of the way through its main sequence lifetime and is spinning with a projected rotational velocity of 68 km/s.[ 6] The star has an estimated 1.8[ 6] times the mass of the Sun and about 1.6[ 7] times the Sun's radius . It is radiating 59[ 3] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,609 K.[ 6]
References
^ a b c d e f 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 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile , 1 , Publicaciones Universidad de Chile, Department de Astronomy: 1– 17, Bibcode :1966PDAUC...1....1G .
^ a b c d e 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 .
^ 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.
^ 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 d e f g h i 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 .
^ a b Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics , 367 (3rd ed.): 521– 524, arXiv :astro-ph/0012289 , Bibcode :2001A&A...367..521P , doi :10.1051/0004-6361:20000451 , S2CID 425754 .
^ "del Pyx" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-07-19 .{{cite web }}
: CS1 maint: postscript (link )
^ 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 .
^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日 Archived 2012-02-04 at the Wayback Machine
^ Frankowski, A.; et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics , 464 (1): 377– 392, arXiv :astro-ph/0612449 , Bibcode :2007A&A...464..377F , doi :10.1051/0004-6361:20065526 , S2CID 14010423 .