Spectroscopy of HD 86222 – a quintuple system with an eclipsing component^⋆,⋆⋆

¹ Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University, Słoneczna 36, 60-286 Poznań, Poland
e-mail: dimitrov@amu.edu.pl
² National Astronomical Observatory Rozhen, PO Box 136, 4700 Smolyan, Bulgaria
³ Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716 Warszawa, Poland
⁴ Centre for Astrophysics and Planetary Science, University of Kent, Canterbury, Kent, CT2 7NH, UK

Received: 12 February 2013
Accepted: 22 January 2014

Abstract

We present spectroscopic and photometric analysis of the quintuple star HD 86222 with an eclipsing component. Until now three visual components A, B, and C of this multiple star were known. Four components in the A/B pair were detected during the examination of the cross correlation functions obtained from the spectra. We noticed that the visual components A and B, separated by , are in fact two binary stars – one eclipsing pair and one spectroscopic system. The pair with higher radial velocity amplitude corresponds to the eclipsing period. Photometric and spectroscopic observations of the eclipsing binary enable us to obtain the Wilson-Devinney model. The masses of this pair are M₁ = 1.29 ± 0.09  M_⊙ and M₂ = 1.33 ± 0.09  M_⊙, respectively. The radii, slightly higher than for the main sequence stars, are R₁ = 1.35 ± 0.01  R_⊙ and R₂ = 1.36 ± 0.01  R_⊙, respectively. The main parameters of the spectroscopic binary are also estimated, but they must be confirmed by future observations because of the uncertainty of the period. The farthest star named C, is 15 arc seconds from the main A and B components. Assuming that this object is gravitationally connected with the A and B binary pairs, HD 86222 has at least five components.