Eva Wirstrom | Searcharxiv

arXiv2023

High resolution study of outflows and chemical environment of First Hydrostatic Core candidate Chamaeleon-MMS1

The earliest stages of low-mass star-formation are unclear, but it has been proposed that Chamaeleon-MMS1 is a candidate First Hydrostatic Core (FHSC), the transition stage between a prestellar and protostellar core. This work describes the local (~4000 AU) outflow activity associated with Chamaeleon-MMS1 and its effect on the surrounding material in order to determine the evolutionary state of this young low-mass source. We used the Atacama Large Millimeter/sub-millimeter Array (ALMA) to observe Chamaeleon MMS1 at 220 GHz at high spatial (~75 AU) and spectral resolutions (0.1-0.3 km/s). A low energy outflow is detected through its interaction with the surrounding cloud. The outflow consists of two components, a broad spectral feature to the northeast and narrow features to both the northeast and southwest. The rotational temperature of formaldehyde (H2CO) is calculated to be 50 (+/-30) K toward the continuum source with similarly low temperatures (25-45 K) toward clumps affected by the outflow. Methanol (CH3OH) is only detected toward gas clumps located away from the continuum source, where the methanol is expected to have been released by the energy of the outflow through ice sputtering in shock waves. Chamaeleon-MMS1 shows outflow activity with the power source being either a single precessing outflow or two outflows from a binary system. While molecular emission and high outflow speeds rule it out as a FHSC, the outflow is less energetic than outflows detected from other Class 0 objects and the inferred gas temperatures toward the continuum source are relatively low, which indicates that Cha-MMS1 is one of the youngest known sources.

astro-ph.SR↗

arXiv2019

Complex Organic Molecules in Star-Forming Regions of the Magellanic Clouds

The Large and Small Magellanic Clouds (LMC and SMC), gas-rich dwarf companions of the Milky Way, are the nearest laboratories for detailed studies on the formation and survival of complex organic molecules (COMs) under metal poor conditions. To date, only methanol, methyl formate, and dimethyl ether have been detected in these galaxies - all three toward two hot cores in the N113 star-forming region in the LMC, the only extragalactic sources exhibiting complex hot core chemistry. We describe a small and diverse sample of the LMC and SMC sources associated with COMs or hot core chemistry, and compare the observations to theoretical model predictions. Theoretical models accounting for the physical conditions and metallicity of hot molecular cores in the Magellanic Clouds have been able to broadly account for the existing observations, but fail to reproduce the dimethyl ether abundance by more than an order of magnitude. We discuss future prospects for research in the field of complex chemistry in the low-metallicity environment. The detection of COMs in the Magellanic Clouds has important implications for astrobiology. The metallicity of the Magellanic Clouds is similar to galaxies in the earlier epochs of the Universe, thus the presence of COMs in the LMC and SMC indicates that a similar prebiotic chemistry leading to the emergence of life, as it happened on Earth, is possible in low-metallicity systems in the earlier Universe.

astro-ph.GA↗