A study of the Herbig Ae-type stars UX Ori and CD -44°3318 based on IUE spectra, and on visual and infrared photometry.

Abstract

Far ultraviolet spectra of the two Herbig Ae stars UX Ori and CD -44°3318 are used to derive spectral types A2 III for UX Ori, and A0 - 1 III for CD -44°3318. The spectral energy distributions are in agreement with that of a Kurucz model with T_eff = 9500K and log g = 4.0. In the near infrared both stars have a large excess of radiation, due to bound-free and free-free emission from a hot circumstellar gas shell, and to thermal re-emission of a dust shell. The positions of the stars in the Hertzsprung-Russell diagram were determined. UX Ori corresponds with a 2 M_sun; pre-main sequence star, whereas CD -44°3318 is situated on the pre-main sequence contraction track of a 2.5 - 3 M_sun; star.