In this paper we present the results of a detailed spectroscopic and photometric analysis of the V=13 ^ { m } .4 low-mass eclipsing binary NSVS 06507557 with an orbital period of 0.515 d. We obtained a series of mid-resolution spectra covering nearly entire orbit of the system .
In addition we obtained simultaneous VRI broadband photometry using a small aperture telescope .
From these spectroscopic and photometric data we have derived the system ’ s orbital parameters and determined the fundamental stellar parameters of the two components .
Our results indicate that NSVS 06507557 consists of a K9 and an M3 pre-main-sequence stars with masses of 0.66 \pm 0.09 M _ { \odot } and 0.28 \pm 0.05 M _ { \odot } and radii of 0.60 \pm 0.03 and 0.44 \pm 0.02 R _ { \odot } , located at a distance of 111 \pm 9 pc .
The radius of the less massive secondary component is larger than that of the zero-age main-sequnce star having the same mass .
While the radius of the primary component is in agreement with ZAMS the secondary component appers to be larger by about 35 % with respect to its ZAMS counterpart .
Night-to-night intrinsic light variations up to 0 ^ { m } .2 have been observed .
In addition , the H _ { \alpha } , H _ { \beta } lines and the forbidden line of [ O i ] are seen in emission .
The Li i 6708 Å absorption line is seen in most of the spectra .
These features are taken to be the signs of the classic T Tauri stars ’ characteristics .
The parameters we derived are consistent with an age of about 20 Myr according to the stellar evolutionary models .
The spectroscopic and photometric results are in agreement with those obtained by theoretical predictions .