Precise Ages of Field Stars from White Dwarf Companions in Gaia DR2

• Published in: The Astrophysical journal. Supplement series Vol. 253; no. 2; p. 58
• Main Authors: Qiu, Dan, Tian, Hai-Jun, Wang, Xi-Dong, Nie, Jia-Lu, Hippel, Ted von, Liu, Gao-Chao, Fouesneau, Morgan, Rix, Hans-Walter
• Format: Journal Article
• Language: English
• Published: Saskatoon IOP Publishing 01.04.2021
• Subjects: Age; Binary stars; Stellar age; Stellar systems; White dwarf stars
• ISSN: 0067-0049; 1538-4365
• DOI: 10.3847/1538-4365/abe468

Abstract We analyze 4050 wide binary star systems involving a white dwarf (WD) and usually a main-sequence (MS) star, drawn from the large sample assembled by Tian et al. Using the modeling code BASE-9, we determine the system’s ages, the WD progenitors’ zero-age MS masses, the extinction values ( A V ), and the distance moduli. Discarding the cases with poor age convergences, we obtain ages for 3551 WDs, with a median age precision of σ τ / τ = 20%, and system ages typically in the range of 1–6 Gyr. We validated these ages against the very few known clusters and through cross validation of 236 WD-WD binaries. Under the assumption that the components are coeval in a binary system, this provides precise age constraints on the usually low-mass MS companions, mostly inaccessible by any other means.