Radial-velocity measurements of subdwarf B stars

Synthetic photometry for non-radial pulsations in subdwarf B stars

We describe a method for computing theoretical photometric amplitude ratios for a number of modes of nonradially pulsating subdwarf B stars in both SDSS and UBVR systems. In order to avoid costly solutions of the non-adiabatic nonradial pulsation equations, we have adopted the adiabatic approximation. We argue that this is a valid approach, at least for the V361 Hya stars, because observations ...

Mass loss predictions for Subdwarf B stars

We present the results of Monte Carlo mass-loss computations for hot low-mass stars, specifically for Subdwarf B (SdB) stars. It is shown that the massloss rates on the Horizontal Branch (HB) computed from radiative line-driven wind models are not high enough to create SdB stars. We argue, however, that mass loss plays a role in the chemical abundance patterns observed both in field SdB stars, ...

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

High-speed spectroscopy of two pulsating subdwarf B stars, KPD2109+4401 and PB8783, is presented. Radial motions are detected with the same frequencies as reported from photometric observations and with amplitudes of ∼ 2 kms in two or more independent modes. These represent the first direct observations of surface motion due to multimode non-radial oscillations in subdwarf B stars. In the case ...

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...

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