Multiyear and multisite photometric campaigns on the bright high-amplitude pulsating subdwarf B star EC 01541-1409

Abstract

We present follow-up observations of the pulsating subdwarf B (sdB) star EC 01541–1409 as part of our efforts to resolve pulsation spectra for use in asteroseismological analyses. This paper reports on data obtained from a single-site campaign, during 2008, and a multisite campaign, during 2009. From limited 2008 data, we were able to clearly resolve and pre-whiten 24 periods. A subsequent multisite campaign spanning nearly 2 months found over 30 individual periodicities most of which were unstable in amplitude and/or phase. Pulsation amplitudes were found to the detection limit, meaning that further observations would likely reveal more periodicities. EC 01541–1409 reveals itself to be one of two sdB pulsators with many pulsation frequencies covering a large frequency range. Unlike the other star of this type (PG 0048+091), it has one high-amplitude periodicity which appears phase stable, making EC 01541–1409 an excellent candidate for exoplanet studies via pulsation phases. No multiplets were detected leaving EC 01541–1409 as yet another rich p-mode sdB pulsator without these features, limiting observational constraints on pulsation modes.