Balloon 090100001: A bright, high amplitude sdB pulsator^*

¹ Instituto de Astrofísica de Canarias, 38200, Spain
² Departamento Física Aplicada, Universidade de Vigo, 36200, Spain e-mail: ulla@uvigo.es; cristinatrl@uvigo.es
³ Departamento Astrofísica, Universidad de La Laguna, 38200, Spain e-mail: fph@ll.iac.es
⁴ Isaac Newton Group of Telescopes, 37800 Santa Cruz de La Palma, Spain e-mail: roy@ing.iac.es
⁵ Department of Physics and Astronomy, University of Delaware, Newark, DE1976, USA e-mail: jimmacd@udel.edu

Corresponding author: R. Oreiro, ror@ll.iac.es

Received: 18 November 2003
Accepted: 8 January 2004

Abstract

We report the discovery of pulsations in the light curve of Balloon 090100001, a bright sdB star () from the balloon-borne survey of Bixler et al. (1991). Our time series observations made with the IAC80 telescope reveal a powerful short period oscillation with a period of 356 s and an amplitude (~59 mmag) only matched in all of the sdB pulsators by the main pulsation of PG 1605+072. The first harmonic (at 178 s) and another independent period (at 264 s) are also present in the amplitude spectrum of this new EC 14026 star. New spectroscopic data from the William Herschel Telescope provide the parameters K and dex. These place Balloon 090100001 in the low temperature and low gravity corner of the sdBV instability region, making it an interesting target for study of possible frequency changes due to stellar evolution.