White dwarf variability with gPhoton : pulsators

• Autor(a) principal: Tucker, Michael A.
• Data de Publicação: 2018
• Outros Autores: Fleming, S.W., Pelisoli, Ingrid Domingos, Romero, Alejandra Daniela, Bell, Keaton, Kepler, Souza Oliveira, Caton, Daniel B., Debes, John, Montgomery, Michael Houston, Thompson, S. E., Koester, Detlev, Million, Chase, Shiao, Bernie
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/179603
• topic: Anãs brancas; Fotometria astronômica; Pulsacoes estelares; Techniques: photometric; Stars: oscillations; White dwarfs; Ultraviolet: stars

We present results from a search for short time-scale white dwarf variability using gPhoton, a time-tagged data base of GALEX photon events and associated software package. We conducted a survey of 320 white dwarf stars in the McCook–Sion catalogue, inspecting each for photometric variability with particular emphasis on variability over time-scales less than∼30 min. From that survey, we present the discovery of a new pulsating white dwarf:WD 2246-069. A Ca II K line is found in archival ESO spectra and an IR excess is seen in WISE W1 and W2 bands. Its independent modes are identified in follow-up optical photometry and used to model its interior structure. Additionally, we detect UV pulsations in four previously known pulsating ZZ Ceti-type (DAVs). Included in this group is the simultaneous fitting of the pulsations of WD 1401-147 in optical, near-ultraviolet and far-ultraviolet bands using nearly concurrent Whole Earth Telescope and GALEX data, providing observational insight into the wavelength dependence of white dwarf pulsation amplitudes.