A predicted astrometric microlensing event by a nearby white dwarf


Type
Article
Change log
Authors
McGill, P 
Smith, LC 
Evans, NW 
Smart, RL 
Abstract

We used the Tycho-Gaia Astrometric Solution catalogue, part of the Gaia Data Release 1, to search for candidate astrometric microlensing events expected to occur within the remaining lifetime of the Gaia satellite. Our search yielded one promising candidate. We predict that the nearby DQ type white dwarf LAWD 37 (WD 1142-645) will lens a background star and will reach closest approach on November 11th 2019 (± 4 days) with impact parameter 380±10 mas. This will produce an apparent maximum deviation of the source position of 2.8±0.1 mas. In the most propitious circumstance, Gaia will be able to determine the mass of LAWD 37 to ∼3%. This mass determination will provide an independent check on atmospheric models of white dwarfs with helium rich atmospheres, as well as tests of white dwarf mass radius relationships and evolutionary theory.

Description
Keywords
gravitational lensing: micro, astrometry, white dwarfs
Journal Title
Monthly Notices of the Royal Astronomical Society: Letters
Conference Name
Journal ISSN
1745-3925
1745-3933
Volume Title
478
Publisher
Oxford University Press (OUP)
Sponsorship
Science and Technology Facilities Council (ST/N000927/1)
STFC (1950369)