Low-Mass Young Stars in Cep OB2: Ages, Distribution and Accretion Disks

摘要

We are studying the young clusters Tr37 and NGC7160 in the Cep OB2 region as part of a program to understand the evolution of accretion disks at the ages of disk dissipation and planet formation. Here, we present the first identifications of low mass (spectral types K-M) members of the clusters and study the presence and characteristics of their accretion disks, finding evidences of disk evolution. Using optical photometry and spectroscopy, we have identified ∼70 members in Tr37 and ∼20 in NGC7160, confirming age estimates of 3 and 10 Myr respectively. Accretion rates are ∼10−8 M ⊙yr−1 in Tr37. We have not found any accreting members in NGC7160, suggesting that disk accretion generally ends before the age of 10 Myr, which is consistent with the results from other populations.