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arXiv · 1804.09059

The sdA problem - II. Photometric and Spectroscopic Follow-up

Ingrid Pelisoli·S. O. Kepler·D. Koester·B. G. Castanheira·A. D. Romero·L. Fraga
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Abstract

Subdwarf A star (sdA) is a spectral classification given to objects showing H-rich spectra and sub-main sequence surface gravities, but effective temperature lower than the zero-age horizontal branch. Their evolutionary origin is an enigma. In this work, we discuss the results of follow-up observations of selected sdAs. We obtained time resolved spectroscopy for 24 objects, and time-series photometry for another 19 objects. For two targets, we report both spectroscopy and photometry observations. We confirm seven objects to be new extremely-low mass white dwarfs (ELMs), one of which is a known eclipsing star. We also find the eighth member of the pulsating ELM class.

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Ingrid Pelisoli, S. O. Kepler, D. Koester, B. G. Castanheira, A. D. Romero, L. Fraga. 2018-04-24. The sdA problem - II. Photometric and Spectroscopic Follow-up. https://doi.org/10.1093/mnras/sty1101

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