Hot molecular cores in young stellar objects of different luminosities

Alvaro Sanchez-Monge (INAF-Osservatorio Astrofisico di Arcetri)

Aina Palau (IEEC-CSIC, Spain), Robert Estalella (UB, Spain), Stan Kurtz (CRyA, Mexico)


First discovered in the vicinity of massive protostars, hot molecular cores (HMCs) are compact (107cm-3) objects with relatively high temperatures (>100K) that show a very rich chemistry in complex organic molecules (e.g., CH3CN, CH3OH, CH3HCO, (CH3)2CO). They are considered to be one of the first evolutionary signposts of massive star formation. However, many questions remain still open regarding HMCs. Must all the protostars undergo the HMC stage? Which is the lifetime of HMCs? Are the HMCs specifically associated with a dominant star formation phenomena?

In this work, we present interferometric observations toward two YSOs of different luminosities (370 Land 70000 L) in order to compare the properties of their hot molecular cores, simultaneously to their outflow, dense gas and radiocontinuum emission. The hot core emission for these two objects appears associated with faint ionized gas emission likely tracing radiojets and molecular outflows, suggesting that HMCs are associated with the stages of accretion and outflow activity. The main difference of both objects is the chemistry of the HMC: low-luminous HMCs could be more rich in OH-bearing molecules, while high-luminous HMCs could be more rich in CN-bearing molecules.