We apply asteroseismic tools to the newly discovered subdwarf B (sdB) pulsator EPIC 203948264, observed with K2, the two-gyro mission of the Kepler space telescope. A time series analysis of the 83-d Campaign 2 (C2) short-cadence data set has revealed a g-mode pulsation spectrum with 22 independent pulsation periods between 0.5 and 2.8 h. Most of the pulsations fit the asymptotic period sequences for ℓ = 1 or 2, with average period spacings of 261.3 ± 1.1 and 151.18 ± 0.37 s, respectively. The pulsation amplitudes are below 0.77 ppt and vary over time. We include updated spectroscopic parameters, including atmospheric abundances and radial velocities, which give no indication for binarity in this star. We detect one possible low-amplitude multiplet, which corresponds to a rotation period of 46 d or longer. EPIC 203948264 appears as another slowly rotating sdB star.
Physics, Astronomy, and Materials Science
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
stars oscillations, stars subdwarfs
Ketzer, L., M. D. Reed, A. S. Baran, P. Németh, J. H. Telting, R. H. Østensen, and C. S. Jeffery. "K2 observations of pulsating subdwarf B stars: analysis of EPIC 203948264 observed during Campaign 2." Monthly Notices of the Royal Astronomical Society 467, no. 1 (2017): 461-468.
Monthly Notices of the Royal Astronomical Society