Orbital solutions for SB2 systems with a HgMn component

Abstract

From a new set of spectroscopic observations we determined orbital parameters of six SB2 systems with one or both components being HgMn stars.We slightly refined the orbital periods for <ASTROBJ>HD 32964</ASTROBJ>, <ASTROBJ>HD 173524</ASTROBJ>, <ASTROBJ>HD 174933</ASTROBJ> and <ASTROBJ>HD 216494</ASTROBJ>. Our results for <ASTROBJ>HD 358</ASTROBJ> are in agreement with the previous literature studies. Regarding <ASTROBJ>HD 33647</ASTROBJ>, our orbital period is shorter than previous determinations. <ASTROBJ>HD 173524</ASTROBJ> is a triple system. From the variations of the γ-velocity deduced from our and literature data, we refined the orbital period and we estimated the eccentricity of the third companion, for which we get e ≈ 0.13 and P<SUB>orb</SUB> = 36 ± 3 years. <ASTROBJ>HD 191110</ASTROBJ> and <ASTROBJ>HD 216494</ASTROBJ> seem to be the only synchronous SB2 within our sample. Following the hypothesis of rotational axes perpendicular to the orbital plane, we estimated the angle of the orbital plane to the line of sight. We identified in our spectra the signature of the H<SUB>β</SUB> of the third component of <ASTROBJ>HD 216494</ASTROBJ> and we highlight a slight variation of the γ-velocity due to the presence of this component.Based on observations collected at the Stellar Station ``M. G. Fracastoro'' of the Catania Astrophysical Observatory, Italy.Appendix A is only available in electronic form at http://www.edpsciences.org