The absorption spectrum of V838 Mon in 2002 February - March. I. Atmospheric parameters and iron abundance

We present a determination of the effective temperatures, iron abundances, and microturbulent velocities for the pseudophotosphere of V838 Mon on 2002 February 25, and March 2 and 26. Physical parameters of the line forming region were obtained in the framework of a self-consistent approach, using fits of synthetic spectra to observed spectra in the wavelength range 5500-6700A. We obtained Tef = 5330, 5540 and 4960 K, for February 25, March 2, and March 26, respectively. The iron abundance log N(Fe)=-4.7 does not appear to change in the atmosphere of V838 Mon from February 25 to March 26, 2002.