Optical observations and cyclops post-shock region modelling of the polar V348 Pav

Abstract

Post-shock regions (PSR) of polar cataclysmic variables produce most of their luminosity and give rise to high circular polarization in optical wavelengths and strong variability on the white dwarf rotation period, which are distinctive features of these systems. To investigate the polar candidate V348 Pav, we obtained a comprehensive observational set including photometric, polarimetric, and spectroscopic data, which was used to constrain the post-shock properties of the system. The object presents high circular polarization (∼ 30 per cent) and high He ii 4686Å to H β line ratio, confirming it is a polar. From both radial velocities and light curves, we determined an orbital period of 79.98 min, close to the orbital period minimum of CVs. The H β radial velocity curve has a semi-amplitude of 141.4±1.5 km s −1 . Doppler tomography showed that most of the spectral line emission in this system is originated in the region of the companion star facing the WD, possibly irradiated by the emission related to the PSR. We modelled the PSR using the cyclops code. The PSR density and temperature profiles, obtained by a proper solution of the hydro-thermodynamic equations, were used in a 3D radiative transfer solution that takes into account the system geometry. We could reproduce the V348 Pav B, V, R, and I photometric and polarimetric data using a model with a WD magnetic field of ∼ 28 MG, a WD mass of ∼ 0.85 M and a low (∼ 25 • ) orbital inclination. These values for the WD mass and orbital inclination are consistent with the measured radial velocities.

Exploratory Spectroscopy of Magnetic Cataclysmic Variables Candidates and Other Variable Objects. II

“…The remaining 30 percent of the sample were classified as extragalactic sources or as other types of variable stars. The first results on followup studies of mCV candidates from Paper I are presented in Silva et al (2015) and Oliveira et al (2019), confirming their polar classification.…”

Breaking the Degeneracy in Magnetic Cataclysmic Variable X-Ray Spectral Modeling Using X-Ray Light Curves

“…To do so, we upgraded the 3D CYCLOPS code (Costa & Rodrigues 2009;Silva et al 2013) such that the PSR is consistently built based on the model parameters. An example of fitting with this new version of the code has been recently performed by Oliveira et al (2019), who investigated the polar V348 Pav in optical wavelengths. In addition, we analyze the properties of the X-ray spectra resulting from the PSR modeling and discuss how model parameters affect them.…”

Breaking the degeneracy in magnetic cataclysmic variable X-ray spectral modeling using X-ray light curves

“…To do so, we upgraded the 3D CYCLOPS code (Costa & Rodrigues 2009;Silva et al 2013) such that the PSR is consistently built based on the model parameters. An example of fitting with this new version of the code has been recently performed by Oliveira et al (2019), who investigated the polar V348 Pav in optical wavelengths. In addition, we analyze the properties of the X-ray spectra resulting from the PSR modeling and discuss how model parameters affect them.…”