August 11-15, 2014


Time series spectroscopic and photometric observations of Massive DAV BPM37093

Atsuko Nitta (Gemini Observatory)

S.O. Kepler (Universidade Federal do Rio Grande do Sul) Andre-Nicolas Chene (Gemini Observatory), S.J. Kleinman (Gemini Observatory), J.L. Provencal (University of Delaware), D.J. Sullivan (Victoria University of Wellington), Paul Chote (Victoria University of Wellington) Ramotholo Sefako (SAAO), D. Koester (University of Kiel), Antonio Kanaan (Universidade Federal de Santa Catarina), Alejandra(Universidade Federal do Rio Grande do Sul), Mariela Corti (Universidad Nacional de La Plata), M.H.Montgomery (University of Texas at Austin), Don Winget (University of Texas at Austin)

BPM 37093 was the first of only a handful of massive (1.05+/-0.05 Msun; Bergeron et al. 2004; sitta 2000) WD pulsators discovered (Kanaan et al. 1992). These stars are particularly interesting because the crystallized mass-fraction as a function of mass and temperature is poorly constrained by observation, yet this process adds a 12 Gyr uncertainty in the ages of the oldest white dwarf stars observed and hence, in the ages of associations that contain them (Abrikosov 1960; Kirzhnitz 1960; Salpeter 1961). Last year, we discovered that ESO uses BPM 37093 as standard star and extracted corresponding spectra from the public archive. The data suggested a variation in the observed hydrogen line profiles that could potentially be due to pulsations, but the measurement did not reach a detection-quality threshold. To further explore this possibility, though, we obtained 4hrs of continuous time series spectroscopy of BPM37093 with Gemini in the Northern Spring of 2014. We present our preliminary results from these data along with those from the accompanying time series photometric observations we gathered from Mt. John (New Zealand), SAAO and PROMPT  to support the Gemini observations.

Mode of presentation: poster