Characterization of intermediate mass young stars from spectral energy distributions and Gaia EDR3

Abstract

Herbig Ae/Be objects (HAeBes) are young, intermediate-mass stars surrounded by protoplanetary disks. From the point of view of star and planet formation, these objects have crucial characteristics. First, their stellar parameters, such as mass or temperature, are between those belonging to the low-mass and high-mass regimes. Second, the presence of bright and large protoplanetary disks makes these stars excellent laboratories to learn how planets form. However, the relatively small amount of known HAeBes sharply contrasts with the large number of their low-mass counterparts. Furthermore, HAeBes have usually been studied on the basis of small samples scattered on the sky, and their stellar and circumstellar parameters have been derived using heterogeneous methodologies. In this contribution I will show the work carried out by Guzmán-Díaz et al. (2021), who provided a homogeneous characterization of a sample of 209 HAeBes from their spectral energy distributions (SEDs) and Gaia EDR3 parallaxes. Using the online tool Virtual Observatory SED Analyzer (VOSA), multi-wavelength photometry of our objects was collected, and the stellar parameters were derived by fitting the optical SEDs with the best Kuruzc models. In addition, the infrared SEDs were classified according to two schemes, and the mass accretion rates, protoplanetary disks masses, and the sizes of dust inner cavities were uniformly estimated. Such a large amount of data allowed us to perform a statistical analysis searching for correlations between the stellar and circumstellar parameters. A major result is that the disk dissipation mechanism in B-type and A-type Herbig stars is most probably different. With the advent of new techniques and more powerful instrumentation, the number of known HAeBes is increasing. A homogeneous stellar and circumstellar characterization, such as the one presented here, will allow us to better understand the formation and evolution of Herbig Ae/Be stars.