2016/10/24 by U. Heber, Heber, Ulrich
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.1610.07516
openalex publication_date 2016/10/24 · openalex created_date 2019/12/05 · openalex updated_date 2026/07/28
Some gaps in the mosaic of binary star evolution have recently been filled by\nthe discoveries of helium-core white dwarf progenitors (often called extremely\nlow mass (ELM) white dwarfs) as stripped cores of first-giant branch objects.\nTwo varieties can be distinguished. One class is made up by SB1 binaries,\ncompanions being white dwarfs as well, another class, the so-called EL CVn\nstars, are composite spectrum binaries, with A-Type companions. Pulsating stars\nare found among both classes. A riddle is posed by the apparently single\nobjects. There is a one-to-one correspondence of the phenomena found for these\nnew classes of star to those observed for sdB stars. In fact, standard\nevolutionary scenarios explain the origin of sdB stars as red giants that have\nbeen stripped close to the tip of first red giant branch. A subgroup of\nsubluminous B stars can also be identified as stripped helium-cores of red\ngiants. They form an extension of the ELM sequence to higher temperatures.\nHence low mass white dwarfs of helium cores and sdB stars in binaries are close\nrelatives in terms of stellar evolution.\n