Binary star in the constellation Cygnus
35 Cygni is a spectroscopic binary star in the constellation Cygnus . Its apparent magnitude is 5.18. Located around 1,000 parsecs (3,300 ly) distant, its primary is a yellow supergiant of spectral type F6Ib, a massive star that has used up its core hydrogen and is now fusing heavier elements.
Yellow supergiants are usually variable, often Classical Cepheid variables , but 35 Cyg is notable for having an especially constant brightness.[ 10]
35 Cyg is a single-lined spectroscopic binary with a period of 2,440 days (over 6 years).[ 11] The secondary cannot be seen directly, nor can its spectral lines be identified but the overall spectrum can be match by a combination of an F4 supergiant and a less luminous B6.5 star.[ 12]
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^ a b Luck, R. Earle (2014). "Parameters and Abundances in Luminous Stars" . The Astronomical Journal . 147 (6): 137. Bibcode :2014AJ....147..137L . doi :10.1088/0004-6256/147/6/137 .
^ Abt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries". The Astrophysical Journal Supplement . 180 (1): 117–118. Bibcode :2009ApJS..180..117A . doi :10.1088/0067-0049/180/1/117 . S2CID 122811461 .
^ Gontcharov, G. A. (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 c d Kovtyukh, V. V.; Gorlova, N. I.; Belik, S. I. (2012). "Accurate luminosities from the oxygen λ7771-4 Å triplet and the fundamental parameters of F-G supergiants" . Monthly Notices of the Royal Astronomical Society . 423 (4): 3268. arXiv :1204.4115 . Bibcode :2012MNRAS.423.3268K . doi :10.1111/j.1365-2966.2012.21117.x . S2CID 118683158 .
^ a b c Lyubimkov, Leonid S.; Lambert, David L.; Kaminsky, Bogdan M.; Pavlenko, Yakov V.; Poklad, Dmitry B.; Rachkovskaya, Tamara M. (2012). "Lithium abundance in atmospheres of F- and G-type supergiants and bright giants" . Monthly Notices of the Royal Astronomical Society . 427 (1): 11–26. arXiv :1212.6057 . Bibcode :2012MNRAS.427...11L . doi :10.1111/j.1365-2966.2012.21617.x . S2CID 119191810 .
^ Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics". Astronomy and Astrophysics . 367 (2): 521. arXiv :astro-ph/0012289 . Bibcode :2001A&A...367..521P . doi :10.1051/0004-6361:20000451 . S2CID 425754 .
^ McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars" . Monthly Notices of the Royal Astronomical Society . 427 (1): 343–357. arXiv :1208.2037 . Bibcode :2012MNRAS.427..343M . doi :10.1111/j.1365-2966.2012.21873.x . S2CID 118665352 .
^ Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood" . Monthly Notices of the Royal Astronomical Society . 402 (2): 1369. arXiv :0911.1335 . Bibcode :2010MNRAS.402.1369L . doi :10.1111/j.1365-2966.2009.15979.x . S2CID 119096173 .
^ Adelman, S. J.; Cay, I. H.; Cay, M. T.; Kocer, D. (2000). "On the Variability of A6 to F9 Supergiants". Information Bulletin on Variable Stars . 4947 : 1. Bibcode :2000IBVS.4947....1A .
^ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I. ; Torres, G.; Udry, S. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics . 424 (2): 727–732. arXiv :astro-ph/0406573 . Bibcode :2004A&A...424..727P . doi :10.1051/0004-6361:20041213 . S2CID 119387088 .
^ Parsons, Sidney B.; Ake, Thomas B. (1998). "Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. V. The Entire IUE Sample" . The Astrophysical Journal Supplement Series . 119 (1): 83. Bibcode :1998ApJS..119...83P . doi :10.1086/313152 .