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arXiv · astro-ph/0510365

Ages of White Dwarf-Red Subdwarf Systems

Hektor Monteiro·Wei-Chun Jao·Todd Henry·John Subasavage·Thom Beaulieu
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Abstract

We provide the first age estimates for two recently discovered white dwarf-red subdwarf systems, LHS 193AB and LHS 300AB. These unusual systems provide a new opportunity for linking the reliable age estimates for the white dwarfs to the (measurable) metallicities of the red subdwarfs. We have obtained precise photometry in the $V_{J}R_{KC}I_{KC}JH$ bands and spectroscopy covering from 6000Åto 9000Åfor the two new systems, as well as for a comparison white dwarf-main sequence red dwarf system, GJ 283 AB. Using model grids available in the literature, we estimate the cooling age as well as temperature, surface gravity, mass, progenitor mass and {\it total} lifetimes of the white dwarfs. The results indicate that the two new systems are probably ancient thick disk objects with ages of at least 6-9 Gyr. We also conduct searches of red dwarf and white dwarf compendia from SDSS data and the L{é}pine Shara Proper Motion (LSPM) catalog for additional common proper motion white dwarf-red subdwarf systems. Only seven new candidate systems are found, which indicates the rarity of these systems.

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Hektor Monteiro, Wei-Chun Jao, Todd Henry, John Subasavage, Thom Beaulieu. 2005-10-12. Ages of White Dwarf-Red Subdwarf Systems. https://doi.org/10.1086/498676

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