Discovery of fourteen new ZZ Cetis with SOAR

¹ Instituto de Física, Universidade Federal do Rio Grande do Sul, 91501-900 Porto-Alegre, RS, Brazil e-mail: kepler@if.ufrgs.br
² SOAR, Casilla 603, La Serena, Chile
³ Sloan Digital Sky Survey, Apache Pt. Observatory, PO Box 59, Sunspot, NM 88349, USA
⁴ Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712, USA
⁵ Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721, USA

Received: 16 June 2005
Accepted: 21 July 2005

Abstract

We report the discovery of fourteen new ZZ Cetis with the 4.1 m Southern Astrophysical Research telescope, at Cerro Pachon, in Chile. The candidates were selected from the SDSS (Sloan Digital Sky Survey) DA white dwarf stars with  obtained from the optical spectra fit, inside the ZZ Ceti instability strip. Considering these stars are multi-periodic pulsators and the pulsations propagate to the nucleus of the star, they carry information on the structure of the star and evolution of the progenitors. The ZZ Cetis discovered till 2003 are mainly within 100 pc from the Sun, and probe only the solar vicinity. The recently discovered ones, and those reported here, may sample a distinct population as they were selected mainly perpendicular to the galactic disk and cover a distance up to ≈ pc.