Oral Presentation
ALMA and JWST synergy in protostellar outflows: the shell-like outflow structures in IRAS 15398-3359
Presenter: Yao-Lun Yang (RIKEN)
Outflows are ubiquitously associated with young protostellar sources. The mass, velocity, and chemistry in outflows constrain accretion, infall, and feedback in the star-forming processes. The dynamical evolution determines the disk formation and evolution, regulating planet formation in the disk. ALMA provides superior angular resolution to map the cool (~10-100 K) gas in outflows, unveiling the gas kinematics and the structures of weakly shocked gas. However, ALMA cannot probe the hot gas that traces the driving jets and winds, which are essential to directly connect outflows to accretion. JWST observations at infrared provides a perfect synergy, measuring the hot shocked gas with comparable angular resolution to that of ALMA. In this talk, I will present the ALMA and JWST observations of the outflow in IRAS 15398-3359 using the data from the CORINOS (JWST) and FAUST (ALMA) programs. This outflow shows four shell-like structures in JWST mid-IR images as well as H2CO emission observed by ALMA. I will show a detailed comparison between the cool molecular gas, observed by ALMA, and the hot gas (H2, [Fe II], and [Ne II]) and dust probed by JWST. Our excitation analysis shows the hot (~1000 K) H2 located within the cool (~50 K) H2CO gas. The hot and cool gas together traces a more complete outflow structure, highlighting the need for both IR and submm observations to characterize outflows. We also find further evidence of jet precession in the last ~10 years, much more recent than the precession indicated by prevous ALMA observations. In this talk, I will discuss possible origins of the observed outflow structures. Furthermore, I will highlight how the WSU upgrade will enable a more efficient outflow survey and the prospect of probing all the mass in outflows using Band 1 observations as well as the synergy with the large FoV JWST imaging.
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