The McDonald Observatory search for pulsating sdA stars: Asteroseismic support for multiple populations
The McDonald Observatory search for pulsating sdA stars: Asteroseismic support for multiple populations
Context. The nature of the recently identified spectroscopic class of star is not well understood. The thousands of known sdAs have H-dominated spectra, spectroscopic surface gravities intermediate to main sequence stars and isolated white dwarfs, and effective temperatures below the lower limit for He-burning subdwarfs. Most are likely products of …