Fundamental parameters and evolutionary state of the Herbig Ae star candidate HD 35929

Abstract

HD 35929 is a pre-main-sequence Herbig Ae star candidate that exhibits emission in the Hα line and a weak IR excess. Although its luminosity type was estimated as IV from low-resolution spectroscopy, the insignificant HIPPARCOS parallax (0.88±0.93 mas) contradicted the low luminosity. To resolve this discrepancy, we took 3 high-resolution optical spectra of the star (region 5200-6915 Å, R ∼60 000) and used an archival one (4000-6800 Å, R ∼48 000). Our analysis of the spectral and photometric information shows that HD 35929 is an F2 III star with T_eff=6880±100 K, log g = 3.3±0.1, log L/L_⊙=1.7±0.2, v sin i =70±5 km s^-1, M=2.3±0.2 M_⊙, a mild metal deficit [Fe/H]=-0.2±0.1, and a weak interstellar reddening (A_V ∼0.1 mag) at a distance D = 345±60 pc. These results confirm an earlier suggestion by Marconi et al. (\cite{marc00}) that HD 35929 is located within the instability strip. At the same time, we argue that it is not a young object, but rather a post-main-sequence giant. The fundamental parameters and IR excess of HD 35929 are similar to those of HD 19993, an emission-line late A-type giant recently discovered by us (Miroshnichenko et al. \cite{mir03}). These objects might represent a group of evolved intermediate-mass stars with an enhanced mass loss.