Radial velocity curve of the spectroscopic binary HD 25639 (ADS 2984A)

Abstract

We present the results of the reduction of our observations for the spectroscopic binary ADS 2984A (B0 II–B0 III), which along with its visual component ADS 2984B (SZ Cam) are the brightest members of the open star cluster NGC 1502. The spectroscopic data were obtained with a fiber-fed echelle spectrograph (R = 15 000) at the 1.2-m telescope of the Astronomical Observatory of the Ural Federal University. The period of ADS 2984A (P_orb = 57.24 ± 0.05 days) has been found for the first time. This spectroscopic binary is shown to belong to the SB1 type. We have determined the parameters of the radial velocity curve for the visible spectroscopic component, V₀ = −5.5 ± 1.2 km s⁻¹ and K = 41.5 ± 1.7 km s⁻¹. The lower mass limit for the invisible spectroscopic component has been estimated to be ~\(5M_ \odot \). Evidence for the presence of a stellar wind outflowing from the surface of this blue giant is presented.