Spectral Types of Planetary Host Star Candidates: Two New Transiting   Planets?
  Recently, 46 low-luminosity object transits were reported from the Optical Gravitational Lensing Experiment. Our follow-up spectroscopy of the 16 most promising candidates provides a spectral classification of the primary. Together with the radius ratio from the transit measurements, we derived the radii of the low-luminosity companions. This allows to examine the possible sub-stellar nature of these objects. Fourteen of them can be clearly identified as low-mass stars. Two objects, OGLE-TR-03 and OGLE-TR-10 have companions with radii of 0.15 R_sun which is very similar to the radius of the transiting planet HD209458B. The planetary nature of these two objects should therefore be confirmed by dynamical mass determinations. 
S. Dreizler, T. Rauch, P. Hauschildt, S.L. Schuh, W. Kley, K. Werner