Search for EC 14026: Results of the survey in the Northern Hemisphere

M. Billères 1 and G. Fontaine 2
1 European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, SANTIAGO 19 , CHILE
2 Département de Physique, Univsersité de Montréal, Succ. Centre ville, CP 6128, Montréal, (Qu) H3C 3J7 , CANADA

 

In 1996, we started a small scale survey in the Northern Hemisphere to look for pulsating hot B subdwarf stars. Among a sample of more than 200 stars (mainly PG objects), we selected on the basis of their effective temperature and gravity - values determined through optical spectroscopy - the interesting candidates. The goals of this survey were :


  1. to discover pulsating sdB stars in the Northern Hemisphere;
  2. to investigate the extent of this phenomenon in the T eff-log g plan;
  3. to determine the degree of purity of the empirical instability strip (or region) in that diagram.
During 3 years, at several telescopes (Mont Bigelow, MDM, Mont Mégantic and CFHT), we tracked with LAPOUNE, a three-channel photometer, the pulsating sdB (named EC 14026, according to the prototype). We present in this poster the means and the strategy we used to complete this survey. All the information we can deduce from this sample are reported: statistics, null results, discussion about the success of your project. And, the most important point, the discovery of 4 pulsating sdB - PG 1047+003, KPD 2109+4401, KPD 1930+2752 and PG 0014+067 - is discussed with the summary of their characteristics and what we know about them thanks to the asteroseismology.

 
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