演講資訊

摘要：

In this talk, I will present a detailed analysis of the Class 0 protostar IRAS 16253-2429, the lowest luminosity (L$\text{bol}$ = 0.2 L$\odot$) and mass (M$*$ = 0.15 M$\odot$) object in the JWST Cycle 1 program, "Investigating Protostellar Accretion" (IPA), complemented by ALMA observations from the "Early Planet Formation in Embedded Disks" (eDisk) program. Our JWST observations reveal a wide, hourglass-shaped continuum cavity and molecular hydrogen (H$_2$) emission, traced across multiple rotational transitions, mapping the wide-angle outflow from the protostar, as also seen in $^{12}$CO from ALMA, which surrounds a highly collimated, fast (170 km/s) [Fe II] jet. We detect 15 pure rotational H$_2$ lines, ranging from H$_2$ 0-0 S(1) to H$_2$ 0-0 S(15), along with H$_2$ 0-0 O and H$_2$ 1-1 S transitions. The outflow, traced by H$_2$ 0-0 S(11), measures 33.6 $\pm$ 1.4 au wide at its base, comparable to the dust disk diameter of 30 au and the Keplerian disk diameter of 32 $\pm$ 6 au, but broader than the 20-23 au width of the [Fe II] jet. Additionally, we find that higher excitation H$2$ components are more collimated, with the outflow's opening angle narrowing as the excitation energy (E$\text{up}$) increases. Position-velocity diagrams reveal that lower excitation H$_2$ lines have velocities of 3-4 km/s, while higher-J lines span a velocity range of 7-10 km/s. These findings provide new insights into the jet and outflow launching mechanisms from protostars.