other querymodes : Identifierquery Coordinatequery Criteriaquery Referencequery Basicquery Scriptsubmission TAP Outputoptions Help

2002ApJ...578..515B - Astrophys. J., 578, 515-522 (2002/October-2)

A survey for pulsating hot B subdwarfs in the northern hemisphere.

BILLERES M., FONTAINE G., BRASSARD P. and LIEBERT J.

Abstract (from CDS):

We present the final results of a survey to search for pulsating hot B subdwarf (sdB) stars. We picked our candidates on the basis of their values of Teffand logg, as estimated from available quantitative optical spectroscopy. With the help of a three-channel photometer, we gathered white-light'' light curves using a uniform sampling time of 10 s for a total of 74 stars. Our survey had a yield of ∼5.4%, leading to the discovery of detectable luminosity variations in four objects: PG 1047+003, KPD 2109+4401, KPD 1930+2752, and PG 0014+067. For the light curves of the other 70 stars, we derive upper limits on the amplitudes of possible periodic signals (in the period window 20-1000 s) that range from ∼0.05% of the mean brightness of the star at an apparent magnitude of y∼12 to ∼0.20% at y∼15. We use our survey results as well as those of others to discuss the location and extent of the empirical instability strip'' for pulsating sdB stars in the logg-Teffdiagram. We also address the question of the coexistence of pulsators and nonvariable stars in the same region of that diagram.