HD191110 a SB2 system with HgMn and Hg components. Orbital elements and abundances analysis

In this paper we present the first quantitative abundance analysis of the SB2 system with HgMn and Hg components HD 191110. Time-resolved (R=14 000) spectroscopic observations of this system have been obtained during September and October 2002 at the Catania Astrophysical Observatory. Combining these observations with spectra (R = 50 000-110 000) taken from the CFHT archive, we refined the orbital period of this system (P=9.34661 +/- 0.00002 d) and then we recalculated the fundamental parameters characterizing its orbit. From the fit of the Hbeta profiles, obtained at different orbital phases, we determined the effective temperatures and surface gravities of each component and the light ratio: TeffA=11 000 K, loggA=3.60, TeffB= 10 700 K, log gB=3.90, LA/LB=1.20. Regarding the chemical composition, both components have solar abundances of sulfur, titanium and iron; magnesium and silicon are slightly underabundant; platinum and yttrium are overabundant. Manganese lines have been detected only in the spectrum of the primary. As to rare-earths, two lines of NdIII have been identified in the secondary's spectrum. Other lines we identified in our spectra belong to PII, CrII, NiII, SrII, ZrII and AuII. We also discuss the isotopic structure of the HgII lambda 3983.9 Å line.