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A&A Supplement series, Vol. 127, January II 1998, 243-249

Received February 26; accepted May 13, 1997

Cyclic phenomena in the circumstellar gaseous envelope of the candidate Herbig A0e star HD163296gif

N.G.Beskrovnayatex2html_wrap1224 - M.A.Pogodintex2html_wrap1224 - R.V.Yudintex2html_wrap1224 - G.A.P.Francotex2html_wrap1230 - S.L.A. Vieiratex2html_wrap1230 - A. Evanstex2html_wrap1234

Send offprint request: N.G.Beskrovnaya

tex2html_wrap1236  Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140 Saint-Petersburg, Russia
tex2html_wrap1238  Departamento de Fısica - ICEX - UFMG, Caixa Postal 702, 30.161-970 - Belo Horizonte - MG, Brazil
tex2html_wrap1240  Department of Physics - Keele University, Keele, Staffordshire ST5 5BG, UK


We present new results of a spectroscopic and polarimetric investigation of the candidate young Herbig Ae/Be star HD163296. Twenty two spectra of this object near the tex2html_wrap_inline1198, HeI 5876 and DNaI lines had been obtained in 1992-1995 at the Astrophysical National Laboratory of Brazil (LNA). In addition, forty seven high-resolution spectra in Htex2html_wrap_inline1200 and Htex2html_wrap_inline1202 were obtained at the ESO (Chile) in 1991-1992. tex2html_wrap_inline1204-polarimetry (about forty measurements of the Stokes parameters tex2html_wrap_inline1206 in each passband) were carried out at the SAAO (South Africa) in July 17-30, 1995.

Striking profile variability has been found in all the lines on time scales from hours to months. Analysis of the profiles revealed manifestations of a remote cool shell which is in active interaction with the variable kinematically stratified stellar wind. Signs of cyclic positional variations of the Htex2html_wrap_inline1200 and Htex2html_wrap_inline1202 emission peaks were observed during five nights in July, 1991.

Sinusoidal variations of the linear polarization parameters detected in July, 1995 are explained in the framework of a model involving magnetized gaseous condensation, rotating in the envelope with the period of 15 days.

Marginal detection of circular polarization is also reported.

keywords: line: profiles -- polarization -- stars: circumstellar matter -- stars: individual (HD163296) -- stars: mass loss -- stars: pre-main sequence

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