Radial velocities of pulsating subdwarf B stars : KPD 2109 + 4401 and PB 8783 ⋆

Radial velocities of pulsating subdwarf B stars: KPD 2109+4401 and PB 8783

Radial velocities of pulsating subdwarf B stars : KPD 2109 1 4401 and PB 8783

High-speed spectroscopy of two pulsating subdwarf B stars, KPD 210914401 and PB 8783, is presented. Radial motions are detected with the same frequencies as reported from photometric observations and with amplitudes of ,2 km s in two or more independent modes. These represent the first direct observations of surface motion arising from multimode non-radial oscillations in subdwarf B stars. In t...

KPD 1930 + 2752 – a candidate Type Ia supernova progenitor

We present spectra of the pulsating sdB star KPD 1930+2752 which confirm that this star is a binary. The radial velocities measured from the Hα and HeI 6678Å spectral lines vary sinusoidally with the same period (2 h 17 m) as the ellipsoidal variability seen byBilì eres et al. (2000). The amplitude of the orbital motion (349.3±2.7 km s −1) combined with the canonical mass for sdB stars (0.5M ⊙)...

2 00 7 Follow - up observations of pulsating subdwarf B stars : Multisite campaigns on PG 1618 + 563 B and PG 0048 + 091

We present follow-up observations of pulsating subdwarf B (sdB) stars as part of our efforts to resolve the pulsation spectra for use in asteroseismological analyses. This paper reports on multisite campaigns of the pulsating sdB stars PG 1618+563B and PG 0048+091. Data were obtained from observatories placed around the globe for coverage from all longitudes. For PG 1618+563B, our five-site cam...

sdB+WD binary with a pulsating subdwarf

The recently discovered subdwarf B (sdB) pulsator KIC 11558725 is one of the 16 pulsating sdB stars detected in the Kepler field. It features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods. This makes it a promising target for a seismic study aiming to constrain the internal structure of this star, and of sdB stars in general. We have obtained ground-based s...