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HgMn in binary systems

From a new set of spectroscopic observations carried out at the stellar station ``M. G. Fracastoro'' Catanzaro and Leto () determined orbital parameters of six SB2 systems with one or both components being HgMn stars.

In particular, they slightly refined the orbital periods for HD32964, HD173524, HD174933 and HD216494. Their results for HD358 are in agreement with the previous literature studies (see Fig. 1.19). Regarding HD33647, the orbital period is shorter than previous determinations. HD173524 is a triple system. From the variations of the $\gamma$-velocity deduced from their own and literature data, they refined the orbital period and they estimated the eccentricity of the third companion, for which they obtained e $\approx$ 0.13 and $P_{\rm orb}$ = 36 $\pm$ 3 years. HD191110 and HD216494 seem to be the only synchronous SB2 within the sample. Following the hypothesis of rotational axes perpendicular to the orbital plane, the authors estimated the angle of the orbital plane to the line of sight. they firstly identified in theis spectra the signature of the H$_{\beta}$ of the third component of HD216494 and highlighted a slight variation of the $\gamma$-velocity due to the presence of this component (see Fig. 1.19).

From this sample the SB2 systems HD191110 and HD216494 have been extracted and presented in a poster paper () at a meeting held in Dubrovnik, Croatia (October 2003)

Figure 1.19: Left panel shows the radial velocity curves for HD358. Right panel shows the composite H$_\beta$ observed in HD216494.
\begin{figure*}\centerline{\hbox{
\psfig{file=stars/hd358.ps,width=8cm}
\psfig{file=stars/hd216494_hbeta.ps,width=8cm}}}\end{figure*}

next up previous contents index
Next: Star Formation Up: Chemical Peculiar stars of Previous: Determination of T and   Contents   Index
Innocenza Busa' 2005-11-14