Orbital solutions for SB2 systems with a HgMn component ^*,**

¹ INAF - Catania Astrophysical Observatory, via S. Sofia 78, 95123, Catania, Italy
² Istituto di Radioastronomia del CNR, Stazione VLBI di Noto, CP 161 Noto, Italy e-mail: pleto@noto.ira.cnr.it

Corresponding author: G. Catanzaro, gcatanzaro@ct.astro.it

Received: 6 October 2003
Accepted: 27 November 2003

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 HD 32964, HD 173524, HD 174933 and HD 216494. Our results for HD 358 are in agreement with the previous literature studies. Regarding HD 33647, our orbital period is shorter than previous determinations. HD 173524 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_orb = 36 ± 3 years. HD 191110 and HD 216494 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 of the third component of HD 216494 and we highlight a slight variation of the γ-velocity due to the presence of this component.