Speaker
Description
The Class I protostellar stage is a critical phase early in stellar evolution, where a rotating disk of gas and dust is formed, setting the chemical budget for the formation of planets. However, unlike the slightly older Class II disks, Class I protostars are deeply embedded in their natal envelopes. With the coverage, sensitivity and spectral resolution of the JWST, we are now capable of characterising their warm inner (<10au) planet-forming regions.
We present new JWST MIRI-MRS spectra of four Class I protostars in the Ophiuchus and Taurus star-forming regions. These spectra, alongside archival spectra, host a large variety of molecular emission and absorption features. Previous CRIRES observations of resolved CO emission for these targets revealed multiple components of emission
with various origins, including disks, outflows and envelopes. By comparing the features observed in MIRI-MRS spectra with these resolved CO line profiles, we aim to disentangle H$_2$O and hydrocarbon emission components from the disk and envelope analogous to those observed in CO. We then apply LTE slab-models to determine the column densities, excitation temperatures and emitting radii for H$_2$O, CO$_2$, OH, HCN and C$_2$H$_2$.
We will show how we can use the line-broadening of emission in the MIRI-MRS spectra to locate the emission, which molecules are associated with disks or outflows in our sample, and the range of excitation conditions present in each component.
Our new observations of Class I disks targeted with JWST-MIRI allow, for the first time, a systematic study of the molecular composition of the disk at the onset of planet formation.
| Talk category | NOVA Network 2 |
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