VLBI astrometry on the white dwarf pulsar AR Scorpii
Journal article, 2023
AR Scorpii (AR Sco), the only-known radio-pulsing white dwarf binary, shows unusual pulsating emission at the radio, infrared, optical, and ultraviolet bands. To determine its astrometric parameters at the radio band independently, we conducted multi-epoch Very Long Baseline Interferometry (VLBI) phase-referencing observations with the European VLBI Network at 5 GHz and the Chinese VLBI Network plus the Warkworth 30-m telescope (New Zealand) at 8.6 GHz. By using the differential VLBI astrometry, we provide high-precision astrometric measurements on the parallax (pi = 8.52(-0.07)(+0.04) mas) and proper motion (mu(alpha) = 9.48(-0.07)(+0.04) mas yr(-1), mu(delta) = -51.32(-0.38)(+0.22) mas yr (-1)). The new VLBI results agree with the optical Gaia astrometry. Our kinematic analysis reveals that the Galactic space velocities of AR Sco are quite consistent with that of both intermediate polars and polars. Combined with the previous tightest VLBI constraint on the size, our parallax distance suggests that the radio emission of AR Sco should be located within the light cylinder of its white dwarf.
white dwarfs
pulsars: individual: AR Sco
radio continuum: stars
techniques: high angular resolution
parallaxes
Author
Pengfei Jiang
Chinese Academy of Sciences
Lang Cui
Chinese Academy of Sciences
Jun Yang
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Bo Zhang
Chinese Academy of Sciences
Shuangjing Xu
Chinese Academy of Sciences
Korea Astronomy and Space Science Institute
Fengchun Shu
Chinese Academy of Sciences
Wu Jiang
Chinese Academy of Sciences
Wen Chen
Chinese Academy of Sciences
Guanghui Li
Chinese Academy of Sciences
Bo Xia
Chinese Academy of Sciences
Stuart Weston
Auckland University of Technology
Sergei Gulyaev
Auckland University of Technology
Hongmin Cao
Shangqiu Normal University
Xiang Liu
Chinese Academy of Sciences
Tao An
Chinese Academy of Sciences
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 520 2 2942-2951Novel EXplorations Pushing Robust e-VLBI Services (NEXPReS)
European Commission (EC) (EC/FP7/261525), 2010-07-01 -- 2013-06-30.
Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Other Physics Topics
DOI
10.1093/mnras/stad327