Orbital periods of cataclysmic variables identified by the SDSS. VI. The 4.5-hr period eclipsing system SDSS J100658.40+233724.4

TL;DR

This paper reports detailed observations and modeling of the eclipsing cataclysmic variable SDSS J100658.40+233724.4, determining its orbital period, component masses, and system properties with high precision.

Contribution

It provides the first comprehensive measurement of the system's parameters, including masses, radii, and temperature, using spectroscopy, photometry, and advanced modeling techniques.

Findings

Orbital period of 0.18591324 days (267.71507 min).

White dwarf mass of 0.78 +/- 0.12 Msun.

Secondary star mass of 0.40 +/- 0.10 Msun and radius of 0.466 +/- 0.036 Rsun.

Abstract

We present time-resolved spectroscopy and photometry of SDSS J100658.40+233724.4, which we have discovered to be an eclipsing cataclysmic variable with an orbital period of 0.18591324 days (267.71507 min). The observed velocity amplitude of the secondary star is 276 +/- 7 km/s, which an irradiation correction reduces to 258 +/- 12 km/s. Doppler tomography of emission lines from the infrared calcium triplet supports this measurement. We have modelled the light curve using the LCURVE code and Markov Chain Monte Carlo simulations, finding a mass ratio of 0.51 +/- 0.08. From the velocity amplitude and the light curve analysis we find the mass of the white dwarf to be 0.78 +/- 0.12 Msun and the masses and radii of the secondary star to be 0.40 +/- 0.10 Msun and 0.466 +/- 0.036 Rsun, respectively. The secondary component is less dense than a normal main sequence star but its properties are in good agreement with the expected values for a CV of this orbital period. By modelling the spectral energy distribution of the system we find a distance of 676 +/- 40 pc and estimate a white dwarf effective temperature of 16500 +/- 2000 K.