Dynamical mass of the white dwarf in XY Ari: a test for intermediate polar X-ray spectral models

A. Álvarez-Hernández; M. A. P. Torres; P. Rodríguez-Gil; T. Shahbaz; J. Sánchez-Sierras; J. A. Acosta-Pulido; P. G. Jonker; K. D. Gazeas; P. Hakala; J. M. Corral-Santana

doi:10.1093/mnras/stad2010

paper

Dynamical mass of the white dwarf in XY Ari: a test for intermediate polar X-ray spectral models

arXiv:2304.08524 · doi:10.1093/mnras/stad2010

Abstract

We present a dynamical study of the eclipsing intermediate polar XY Ari based on time-resolved near-infrared spectroscopy obtained with the EMIR spectrograph on the 10.4-m Gran Telescopio Canarias. Using main sequence template spectra taken with the same instrument setup as the target spectra, we measure a radial velocity amplitude of the late K-type donor star $K_{2} = 256 \pm 2$ km s $^{- 1}$ . We also obtain the rotational broadening of its photospheric lines $v_{rot} sin i = 141 \pm 3$ km s $^{- 1}$ . From these and the eclipse geometry, we derive a donor-to-white-dwarf mass ratio $q = M_{2} / M_{1} = 0.62 \pm 0.02$ , an orbital inclination $i = 80. 8^{\circ} \pm 0. 5^{\circ}$ and dynamical masses $M_{1} = 1.21 \pm 0.04 M_{⊙}$ and $M_{2} = 0.75 \pm 0.04 M_{⊙}$ ( $1 σ$ ). This result places the white dwarf in XY Ari as one of the three most massive known in a cataclysmic variable. Comparison with white dwarf mass estimates from X-ray spectral studies could indicate the necessity of an improvement of the X-ray models and/or analysis techniques, as a number of X-ray white dwarf masses are in disagreement with the dynamical mass value.

arXiv comment10 pages, 4 figures, 5 tables, accepted for publication in MNRAS

Dynamical mass of the white dwarf in XY Ari: a test for intermediate polar X-ray spectral models

Abstract

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