Spectroscopic variabilities in lambda Pavonis

Autor(es)

Levenhagen, R. S. ^[1] ; Leister, N. V. ^[2] ; Kuenzel, R. ^[3]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Paulo, Dept Ciencias Exatas & Terra, BR-09972270 Diadema, SP - Brazil

^[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Fis, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Astronomy & Astrophysics; v. 533, SEP 2011.
• Citações Web of Science: 1

Resumo

Aims. We investigate the time-varying patterns in line profiles, V/R, and radial velocity of the Be star HD 173948 (lambda Pavonis). Methods. Time series analyses of radial velocity, V/R, and line profiles of He I, Fe II, and Si II were performed with the Cleanest algorithm. An estimate of the stellar rotation frequency was derived from the stellar mass and radius in the Roche limit by adopting an aspect angle i derived from the fittings of non-LTE model spectra affected by rotation. The projected rotation velocity, necessary as input for the spectral synthesis procedure, was evaluated from the Fourier transform of the rotation profiles of all neutral helium lines in the optical range. Results. Emission episodes in Balmer and He i lines, as well as V/R cyclic variations, are reported for spectra observed in year 1999, followed by a relatively quiescent phase (2000) and then again a new active epoch (2001). From time series analyses of line profiles, radial velocities, and V/R ratios, four signals with high confidence levels are detected: nu(1) = 0.17 +/- 0.02, nu(2) = 0.49 +/- 0.05, nu(3) = 0.82 +/- 0.03, and nu(4) = 1.63 +/- 0.04 c/d. We interpret nu 4 as a non-radial pulsation g-mode, nu 3 as a signal related to the orbital timescale of ejected material, which is near the theoretical rotation frequency 0.81 c/d inferred from the fitting of the models taken into account for gravity darkening. The signals nu(1) and nu(2) are viewed as aliases of nu(3) and nu(4). (AU)

• Processo FAPESP: 98/10138-8 - Espectroscopia de média e alta resolução: abundâncias químicas e populações estelares
• Beneficiário: Beatriz Leonor Silveira Barbuy
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 04/14256-8 - Estudo de estrelas B e Be pertencentes ao halo galáctico
• Beneficiário: Ronaldo Savarino Levenhagen
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado