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Photometric and spectral observations of two W UMa stars with periods of one third of a day
Author(s) -
Kjurkchieva D. P.,
Marchev D. V.,
Popov V. A.
Publication year - 2018
Publication title -
astronomische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.394
H-Index - 63
eISSN - 1521-3994
pISSN - 0004-6337
DOI - 10.1002/asna.201813483
Subject(s) - physics , astrophysics , light curve , orbital inclination , radial velocity , stars , stellar classification , mass ratio , binary number , arithmetic , mathematics
Photometric and spectral observations of the W UMa binaries NSVS 254037 and V505 Lac with periods of around 8 hr are presented. The simultaneous light curve and radial velocity curve solutions revealed that their components are of G spectral type. The two targets undergo partial eclipses. They both have overcontact configurations of W subtype with fill‐out factor f ∼ 0.1. The derived parameters of NSVS 254037 are: mass ratio q = 2.42; orbital inclination i = 67.1°; temperatures T 1 = 5800 K and T 2 = 5585 K; masses M 1 = 0.47 M ⊙ and M 2 = 1.15 M ⊙ ; radii R 1 = 0.72 R ⊙ and R 2 = 1.07 R ⊙ ; luminosities L 1 = 0.53 L ⊙ and L 2 = 1.0 L ⊙ ; equatorial velocities V 1 = 89 km −1 and V 2 = 146 km −1 ; and distance d = 175 pc, almost the same as those of GAIA(DR2). The derived parameters of V505 Lac are: mass ratio q = 2.53; orbital inclination i = 57.3 0 ; temperatures T 1 = 5,600 K and T 2 = 5,166 K; masses M 1 = 0.38 M ⊙ and M 2 = 0.97 M ⊙ ; radii R 1 = 0.69 R ⊙ and R 2 = 1.04 R ⊙ ; luminosities L 1 = 0.41 L ⊙ and L 2 = 0.68 L ⊙ ; equatorial velocities V 1 = 106 km −1 and V 2 = 129 km −1 ; and distance d = 117 pc, smaller than those of GAIA by 19%. Thus, NSVS 254037 and V505 Lac turned out similar not only in periods and magnitudes but also in mass ratios, radii, and fill‐out factors.