Binary star system in the constellation Draco
6 Draconis is a single-lined spectroscopic binary [ 4] star system in the northern constellation of Draco , located about 430 light years away from the Sun. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.95.[ 2] radial velocity of 3 km/s.[ 2]
The variable radial velocity of this star system was announced by W. W. Campbell in 1922. Griffin et al. (1990) found an orbital period of 1.5 yr and an eccentricity of 0.26. The primary has an "a sin i " value of 51.4 Gm (0.34 AU ), where a is the semimajor axis and i is the (unknown) orbital inclination . This value provides a lower bound on the actual semimajor axis, which is one half of the longest dimension of their elliptical orbit.[ 4]
The visible component is an evolved giant star with a stellar classification of K2.5 III Fe-2 ,[ 3] spectrum . The measured angular diameter of this star, after correction for limb darkening , is ± 0.04 mas [ 9] radius of the Sun .[ 5] [ 2] Sun's luminosity from its enlarged photosphere at an effective temperature of 4,210 K.[ 6] A-type main-sequence star with a class of A8–9 V.[ 4]
References
^ a b c d e 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 e f g h 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 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series , 71 : 245, Bibcode :1989ApJS...71..245K , doi :10.1086/191373 . ^ a b c d e Griffin, R. F.; et al. (June 1990), "The spectroscopic orbit of 6 Draconis", Journal of Astrophysics and Astronomy , 11 (2): 255, Bibcode :1990JApA...11..255G , doi :10.1007/BF02715020 , S2CID 120297735 ^ a b Lang, Kenneth R. (2006), Astrophysical formulae Birkhäuser , ISBN 3-540-29692-1 * ) is given by:
2
⋅
R
∗
=
(
132.7
⋅
2.54
⋅
10
−
3
)
AU
0.0046491
AU
/
R
⨀
≈
72.5
⋅
R
⨀
{\displaystyle {\begin{aligned}2\cdot R_{*}&={\frac {(132.7\cdot 2.54\cdot 10^{-3})\ {\text{AU}}}{0.0046491\ {\text{AU}}/R_{\bigodot }}}\\&\approx 72.5\cdot R_{\bigodot }\end{aligned}}}
^ a b c d McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series , 74 : 1075– 1128, Bibcode :1990ApJS...74.1075M , doi :10.1086/191527 ^ De Medeiros, J. R.; et al. (October 2002), "The Rotation of Binary Systems with Evolved Components", The Astrophysical Journal , 578 (2): 943– 950, arXiv :astro-ph/0207288 Bibcode :2002ApJ...578..943D , doi :10.1086/342613 , S2CID 16196039 . ^ "6 Dra" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 2019-01-23 .^ Richichi, A.; Percheron, I.; Khristoforova, M. (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
