A new absolute magnitude calibration with 2MASS for cataclysmic variables

Using reliable trigonometric measurements, we find that the absolute magnitude of cataclysmic variables depends on the orbital period and de-reddened $(J-H)_{0}$ and $(H-K_{s})_{0}$ colours of {\em 2MASS} (Two Micron All Sky Survey) photometric system. The calibration equation covers the ranges $0.032^{d} < P_{orb} \leq 0.454^{d}$, $-0.08 < (J-H)_{0} \leq 1.54$, $-0.03 <(H-K_{s})_{0} \leq 0.56$ and $2.0 < M_{J} < 11.7$; It is based on trigonometric parallaxes with relative errors of $(\sigma_{\pi}/\pi) \leq 0.4$. By using the period-luminosity-colours (PLCs) relation, we estimated the distances of cataclysmic variables with orbital periods and {\em 2MASS} observations and compared them with distances found from other methods. We suggest that the PLCs relation can be a useful statistical tool to estimate the distances of cataclysmic variables.