DETERMINING THE ACCRETION CRITERION FOR YOUNG ACCRETING LATE-M DWARFS IN NEARBY ASSOCIATIONS

Abstract

Studying young accreting very low-mass objects (late-M and brown dwarfs) in nearby associations will shed lights into their formation mechanism at different stages. Therefore, the identification of these bona-fide accreting objects is the first important step for further studies. The 10% width of Hα emission profile with a value of about 200 km.s^-1 has widely been used to detect young accreting brown dwarfs in star-forming regions. However, there has not been any independent criterion to verify the accreting and non-accreting nature of the detected objects, especially objects detected in young nearby associations. Based on the Wide Infrared Survey Explorer data, a small sample of previously identified accreting and non-accreting late-M and brown dwarfs in starforming regions and young nearby associations was collected to construct their spectral energy distribution. The results of this study which were based on infrared excesses are aligned with the previous works. It is suggested that the Hα 10% velocity width at 200 km.s^-1 could be applied for identifying accreting very low-mass objects in young associations.