Discovery of five new massive pulsating white dwarf stars

• Autor(a) principal: Castanheira, Bárbara Garcia
• Data de Publicação: 2013
• Outros Autores: Kepler, Souza Oliveira, Kleinman, Scot James, Nitta, Atsuko, Fraga, Luciano
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/93384
• topic: Anãs brancas; Massa estelar; Pulsacoes estelares; Telescópios astronômicos; White dwarfs

Using the SOuthern Astrophysical Research telescope (SOAR) Optical Imager at the SOAR 4.1 m telescope, we report on the discovery of five new massive pulsating white dwarf stars. Our results represent an increase of about 20 per cent in the number of massive pulsators. We have detected both short and long periods, low and high amplitude pulsation modes, covering the whole range of the ZZ Ceti instability strip. In this paper, we present a first seismological study of the new massive pulsators based on the few frequencies detected. Our analysis indicates that these stars have masses higher than average, in agreement with the spectroscopic determinations. In addition, we study for the first time the ensemble properties of the pulsating white dwarf stars with masses above 0.8 Mʘ. We found a bimodal distribution of the main pulsation period with the effective temperature for the massive DAVs, which indicates mode selection mechanisms.