Dissecting the donor star in the eclipsing polar HU Aquarii

A. D. Schwope*, K. Horne, D. Steeghs, M. Still

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

Medium-resolution spectroscopic observations with full phase coverage of the eclipsing polar HU Aqr are presented. Na I absorption and Ca II emission lines are used to trace the secondary star. While the Na I lines seem to have contributions from both hemispheres of the donor star, the Ca II lines were found to originate from the irradiated part of its surface alone. An irradiation model was applied and the irradiation-weighted radial velocity amplitude was used to determine the mass ratio Q = M(WD)/M(2) = 4.58 +/- 0.20. When combined with high-speed photometric low-state eclipse light curves, the white dwarf mass is constrained to 0.75 <M(WD)/M(circle dot) <0.84 with a best-fit value of M(WD) = (0.80 +/- 0.04) M(circle dot), and M(2) = (0.18 +/- 0.06) M(circle dot) at an orbital inclination of i = 87(-0.5)(o+0.8).

Original languageEnglish
Article number34
Number of pages6
JournalAstronomy & Astrophysics
Volume531
DOIs
Publication statusPublished - Jul 2011

Keywords

  • binaries: eclipsing
  • stars: variables: general
  • CATACLYSMIC VARIABLES
  • ACCRETION STREAM
  • WHITE-DWARF
  • QQ-VUL
  • AM-HER
  • SECONDARY
  • AQR
  • SPECTROSCOPY
  • TOMOGRAPHY
  • DISCOVERY

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