Speaker
Description
How the chemistry in the universe evolves from diffuse interstellar medium to a life-harboring environment on our Earth? Complex organic molecules (COMs), typically defined as carbon-bearing molecules with at least six atoms, have gained their popularity over the past several decades due to their importance of linking atoms and simple molecules with prebiotic species. COMs are suggested to be first formed in ice mantles of dust grains during the cold pre-stellar phase, and then sublimated into the gas phase when temperature goes up in the hot core phase. Gas-phase COMs can be observed in (sub)millimeter wavelengths using radio telescopes like ALMA, which is the most powerful one and has detected a rich inventory of COMs in star-forming regions, mostly in Class 0 protostars. The detection of solid-phase COMs (i.e., COM ices) was only confirmed for methanol (CH3OH), the simplest COM, but is now becoming promising for other COMs using JWST and its Mid-InfraRed Instrument (MIRI). The absorption bands of COM ices mainly fall in the mid-infrared, especially the fingerprint region between 6.8 and 8.8 µm that contains a series of vibrational modes of oxgen-bearing COMs (O-COMs). Tracing COMs in both phases in young stellar objects (YSOs) can help us probe their formation history, and shed light on how the chemistry evolves from simple to complex in the universe. We will show the results from the latest ALMA and JWST observations with a nonexclusive focus on O-COMs, which are relatively abundant and therefore more detectable for both telescopes. We start with case studies on two low-mass protostars that are famous for their rich COM chemistry in both gas and ice, NGC 1333 IRAS 2A and B1-c, as part of our JWST Observations of Young protoStars (JOYS+) program. By comparing the ratios between O-COMs and the reference species such as H2O and CH3OH, we find that COMs are likely to be inherited from ice to gas, while there is also evidence of gas-phase reprocessing that alters the COM ratios in the two phases. A more statistical study on a larger JOYS+ sample is undergoing.
| Talk category | NOVA Network 2 |
|---|---|
| Preference for a talk or poster | Talk |
| Talk preference for PhD students | 4th-year |
