Open AccessContribution to the search for binaries among Am stars – IV. HD 100054B and 187258
Author(s) -
Ginestet N.,
Prieur J.L.,
Carquillat J.M.,
Griffin R. F.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06489.x
Subject(s) - physics , astrophysics , orbital period , stars , orbital elements , radial velocity , orbital motion , orbit (dynamics) , binary number , binary star , light curve , circular orbit , orbital inclination , astronomy , angular momentum , arithmetic , mathematics , engineering , quantum mechanics , aerospace engineering
Radial velocity observations of HD 100054B and 187258 with CORAVEL instruments at Haute‐Provence and Cambridge Observatories are reported. Known as Am/Fm metallic‐line stars, both objects were included in our spectroscopic survey of Am‐type stars, the purpose of which was to determine the frequency and properties of binaries in this stellar family. HD 100054B is found to be a single‐lined spectroscopic binary with a variable value of V 0 , the systemic velocity of the centre of gravity of the pair. The variation of this parameter is interpreted in terms of orbital motion of an unseen third body with a much longer period. The orbital elements are derived for both the short‐ and the long‐period orbits. We find P = 12.794 30 d, T = 244 9781.19 HJD, ω= 137°, e = 0.028, K 1 = 18.69 km s −1 , a 1 sin i = 3.29 Gm and f ( m ) = 0.0087 M ⊙ for the short‐period orbit; and P = 874.2 d, T = 244 9377 HJD, ω= 172°, e = 0.097, K 1 = 5.30 km s −1 , V 0 =−13.52 km s −1 , a 1 sin i = 63.4 Gm and f ( m ) = 0.013 M ⊙ for the long‐period orbit. HD 187258 is found to be a single‐lined spectroscopic binary, the orbital elements of which are P = 25.8048 d, T = 244 9628.91 HJD , , e = 0.370, K 1 = 17.36 km s −1 , V 0 =−34.76 km s −1 , a 1 sin i = 5.72 Gm and f ( m ) = 0.011 M ⊙ . Physical parameters of the primary components of these systems are derived.