Whole earth telescope observations of the interacting binary white dwarf v803 cen in its low state

• Autor(a) principal: O'Donoghue, Darragh
• Data de Publicação: 1990
• Outros Autores: Wargau, W., Warner, B., Kilkenny, Dave, Martinez, Peter, Kanaan Neto, Antonio Nemer, Kepler, Souza Oliveira, Henry, G.W., Winget, Donald Earl, Clemens, J. Christopher, Grauer, Albert D.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/88364
• topic: Astrofísica; Anãs brancas; Fotometria; Tecnicas oticas de alta velocidade

Using a network of observatories in the southern hemisphere, high-speed photometry of the interacting binary white dwarf (IBWD) V803 Cen in its low state is presented. Because of the faintness of the system, the 1611-s oscillation, reported in previous studies when V803 Cen was near maximum, was difficult to distinguish from the noise in many of the individual high-speed photometric runs; it was, however, unambiguously detected in combinations of runs. No evidence for the presence of either its harmonics or the previously observed 175-s oscillation was found. Low state optical spectroscopy of V803 Cen confirmed the presence of weak He emission lines which had been suspected in an earlier study. The line profiles showed evidence of doubling, typical of an accretion disc, and varied in strength, possibly correlated with system luminosity. The breadths of the emission lines were similar to those of the He absorption lines seen near maximum, suggesting that the same mechanism, Stark broadening, is responsible. The He emission-line strengths indicate that the lines are optically thick and their weakness at times suggests that the continuum is nearly optically thick; the construction of detailed hydrogen-deficient disc models to account for these properties is urged.