Recent research has unveiled significant findings regarding star formation and interstellar chemistry in the Large Magellanic Cloud (LMC). A survey conducted using the Atacama Large Millimeter/submillimeter Array (ALMA) focused on 30 massive protostellar objects. This study aims to enhance our understanding of star formation under conditions of subsolar metallicity, revealing critical insights into hot cores in the LMC.
The survey, which employed observations at 350 GHz, identified a total of 36 compact sources. Among these, the research team, led by Takashi Shimonishi and Kei E. I. Tanaka, confirmed the presence of nine hot cores and one hot-core candidate, including two newly identified sources.
The analysis detected a range of molecules including carbon monoxide (CO), methanol (CH3OH), and sulfur dioxide (SO2), among others. Notably, the detection of CH3OCH3, a complex organic molecule larger than methanol, marks its first identification in a hot core outside the LMC bar region. This finding broadens our understanding of chemical complexity in extraterrestrial environments.
Key Chemical Findings in Hot Cores
The study revealed that all identified hot cores exhibited stronger emissions in the high-excitation SO line compared to non-hot-core sources. This trend suggests that detecting this line could serve as a reliable method for identifying hot-core candidates within the LMC. Additionally, a significant variation was observed in the abundances of methanol, with some sources showing a deficiency in complex organic molecules (COMs). In contrast, sulfur dioxide was consistently detected in all hot cores, exhibiting a strong correlation with rotational temperature.
The hot cores lacking methanol detection were primarily located outside the LMC bar region, characterized by either high luminosity or active star formation in their vicinity. These observations imply that a combination of low metallicity, high protostellar luminosity, and vigorous star formation could contribute to the unique hot core chemistry observed in the LMC.
The spatial distribution of the hot cores was illustrated in the study, with those showing methanol detection indicated by magenta squares and those without by cyan squares. The remaining sources were marked in white. This distribution highlights the association of various hot cores with prominent regions such as 30 Dor and N11, known for their intense star formation activity.
Overall, the findings from this survey deepen our understanding of the chemical processes occurring in the LMC and offer crucial insights into the dynamics of star formation in environments that differ from our own. This research has been accepted for publication in the Astrophysical Journal Supplement and provides a foundation for future studies aimed at unraveling the complexities of interstellar chemistry in various cosmic locales.
