Classification and disk parameters of Herbig Ae/Be stars using WISE and AKARI data

摘要

We present the classification and disk parameters of 50 Herbig Ae/Be stars using WISE and AKARI data. These stars have been classified into 4 groups based on the scheme proposed by Koenig et al. (2012) using WISE pass bands and by constructing their SEDs using data up to 12 pass bands. We could successfully classify 18 sources as Class I, 22 as Class II, 6 as Class III and 4 as sources with transitional disk. One-third of the sample (classification of 14 of 50 and disk parameters of 19 of 50) were studied for the first time. SEDs created with and without AKARI data were found to be similar for a good fraction of sources, though some sources showed large deviation. The SEDs are also used to derive the stellar as well as the circumstellar disk parameters. Our analysis suggests that sources more massive than ~ 6 M_⊙ may have a very short Class II phase. We have studied the correlation between various stellar and disk parameters. Among the present sample, this study tentatively suggests that one set of stars are found to lose their disk rapidly, within 3-4 Myr, whereas another set of sources are found to retain their disk as well as accretion till 6-8 Myr.