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

Sewiło, M.; Charnley, Steven B.; Schilke, P.; Taquet, V.; Oliveira, J. M.; Shimonishi, Takashi; Wirström, E. S.; Indebetouw, R.; Ward, Jason; Loon, Jacco Th. van; Wiseman, Jennifer; Zahorecz, Sarolta; Onishi, Toshikazu; Kawamura, Akiko; Chen, C.-H. Rosie; Fukui, Y.; Golshan, Roya Hamedani

doi:10.1021/acsearthspacechem.9b00065

Cited by 18 publications

(16 citation statements)

References 166 publications

(418 reference statements)

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“…Prior to the present study, COMs with more than six atoms had only been detected toward two hot cores in the LMC: A1 and B3 in the star-forming region N 113 (N 113 A1 and N 113 B3;Sewiło et al 2018Sewiło et al , 2019. Sewiło et al (2018) reported the detection of methyl formate (HCOOCH 3 ) and dimethyl ether (CH 3 OCH 3 ), together with their likely parent species CH 3 OH, with fractional abundances with respect to H 2 (corrected for a reduced metallicity in the LMC with respect to the Milky Way) at the lower end, but within the range measured toward Galactic hot cores.…”

Section: Hot Molecular Cores In the Lmcmentioning

confidence: 78%

“…A typical Galactic hot core has a very rich spectrum at submm wavelengths including lines from many complex organics -the products of interstellar grain-surface chemistry or postdesorption gas chemistry (e.g., Herbst & van Dishoeck 2009;Oberg 2016;Jørgensen et al 2020). Methanol has also been detected toward a handful of other locations in the LMC, but outside hot cores ("cold methanol"; see e.g., Sewiło et al 2019).…”

Section: Hot Molecular Cores In the Lmcmentioning

confidence: 99%

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ALMA Observations of Molecular Complexity in the Large Magellanic Cloud: The N105 Star-Forming Region

Sewiło,

Cordiner,

Charnley

et al. 2022

Preprint

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The Large Magellanic Cloud (LMC) is the nearest laboratory for detailed studies on the formation and survival of complex organic molecules (COMs), including biologically important ones, in lowmetallicity environments-typical for earlier cosmological epochs. We report the results of 1.2 mm continuum and molecular line observations of three fields in the star-forming region N 105 with the Atacama Large Millimeter/submillimeter Array (ALMA). N 105 lies at the western edge of the LMC bar with on-going star formation traced by H 2 O, OH, and CH 3 OH masers, ultracompact H ii regions, and young stellar objects. Based on the spectral line modeling, we estimated rotational temperatures, column densities, and fractional molecular abundances for twelve 1.2 mm continuum sources. We identified sources with a range of chemical make-ups, including two bona fide hot cores and four hot core candidates. The CH 3 OH emission is widespread and associated with all the continuum sources. COMs CH 3 CN and CH 3 OCH 3 are detected toward two hot cores in N 105 together with smaller molecules typically found in Galactic hot cores (e.g., SO 2 , SO, and HNCO) with the molecular abundances roughly scaling with metallicity. We report a tentative detection of the astrobiologically relevant formamide molecule (NH 2 CHO) toward one of the hot cores; if confirmed, this would be the first detection of NH 2 CHO in an extragalactic sub-solar metallicity environment. We suggest that metallicity inhomogeneities resulting from the tidal interactions between the LMC and the Small

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Section: Hot Molecular Cores In the Lmcmentioning

confidence: 78%

Section: Hot Molecular Cores In the Lmcmentioning

confidence: 99%

ALMA Observations of Molecular Complexity in the Large Magellanic Cloud: The N105 Star-Forming Region

Sewiło,

Cordiner,

Charnley

et al. 2022

Preprint

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“…While this model has been applied to meteoritic amino acids, we note that other organic molecules have been found in meteorites [e.g., [107][108][109][110][111][112] and comets [113], and the search for extraterrestrial organic molecules remains an active field in observational astronomy [e.g., [114][115][116][117] and planetary science [e.g., [118][119][120][121][122]. However, in addition to chiral amino acids, other chiral organic molecules have been found in meteorites with non-zero enantiomeric excesses [123,124] as well as isotopic ratios which differ from terrestrial values [124].…”

Section: Discussionmentioning

confidence: 99%

Chiral Selection, Isotopic Abundance Shifts, and Autocatalysis of Meteoritic Amino Acids

Famiano,

Boyd,

Onaka

et al. 2021

Preprint

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The discovery of amino acids in meteorites has presented two clues to the origin of their processing subsequent to their formation: a slight preference for left-handedness in some of them, and isotopic anomalies in some of their constituent atoms. Numerous models have been developed to explain these phenomena. In this article we present theoretical results from the Supernova Neutrino Amino Acid Processing (SNAAP) model, which uses electron anti-neutrinos and the magnetic fields from source objects such as supernovae or colliding neutron stars to selectively destroy one amino acid chirality, and the same anti-neutrinos to create isotopic anomalies. For plausible magnetic fields and electron anti-neutrino fluxes, non-zero, positive enantiomeric excesses, ees, defined to be the relative left/right asymmetry in an amino acid population, are reviewed for two amino acids, and conditions are suggested that would produce ee > 0 for all of the α-amino acids. This is accomplished by electron anti-neutrinos produced by the cosmic object interacting with the 14 N nuclei in the amino acids. The relatively high energy anti-neutrinos that produce the ees would inevitably also produce isotopic anomalies. A nuclear reaction network was developed to describe the reactions resulting from them and the nuclides in the meteorites. At similar anti-neutrino fluxes, assumed recombination of the detritus from the anti-neutrino interactions is shown to produce appreciable isotopic anomalies in qualitative agreement with those observed for D/ 1 H and 15 N/ 14 N. The isotopic anomalies for 13 C/ 12 C are predicted to be small, as are also observed. Autocatalysis, a chemical enrichment of a small imbalance, may be necessary for the SNAAP model, or for any model suggested so far, to produce the largest ees observed in meteorites. Thus a new autocatalysis model is developed that includes both the spins of the nuclei and the chirality of the amino acids. Autocatalysis allows the constraints of the original SNAAP model to be relaxed, providing more flexibility in its application, and increasing the probability of meteoroid survival in sites where amino acid processing is possible. The SNAAP Model thus explains all of the observed phenomena related to processing of the amino acids in meteorites. These results have obvious implications for the origin of life on Earth.

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“…N113, located in the central part of the LMC, contains the most intense H 2 O maser of the Magellanic Clouds (Ellingsen et al 2010), which indicates active star formation activity at an early stage. A large number of molecular transitions have been reported in N113 (e.g., Chin et al 1996Chin et al , 1997Heikkilä et al 1998;Wang et al 2009;Paron et al 2014;Nishimura et al 2016;Tang et al 2017b;Sewiło et al 2018Sewiło et al , 2019, while interferometric data from HCN, HCO + , HNC, CH 3 OH, and 1.3 mm continuum (Wong et al 2006;Seale et al 2012;Sewiło et al 2018Sewiło et al , 2019 reveal a filamentary structure elongated roughly North-South with a length of ∼6 pc, including a few dense clumps with radius ∼0.5 pc. N159W, located at the southwestern tip of 30 Doradus, one of the most intense star-forming regions in the LMC, contains a large number of O-and B-type stars, embedded young stellar objects (YSOs), and ultracompact H II regions (e.g., Jones et al 2005;Fariña et al 2009;Chen et al 2010;Carlson et al 2012).…”

Section: Targetsmentioning

confidence: 99%

Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde IV. The ALMA view of N113 and N159W in the LMC

Tang,

Henkel,

Menten

et al. 2021

Preprint

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We mapped the kinetic temperature structure of two massive star-forming regions, N113 and N159W, in the Large Magellanic Cloud (LMC). We have used ∼1 . 6 (∼0.4 pc) resolution measurements of the para-H 2 CO J KaKc = 3 03 -2 02 , 3 22 -2 21 , and 3 21 -2 20 transitions near 218.5 GHz to constrain RADEX non-LTE models of the physical conditions. The gas kinetic temperatures derived from the para-H 2 CO line ratios 3 22 -2 21 /3 03 -2 02 and 3 21 -2 20 /3 03 -2 02 range from 28 to 105 K in N113 and 29 to 68 K in N159W. Distributions of the dense gas traced by para-H 2 CO agree with those of the 1.3 mm dust and Spitzer 8.0 µm emission, but do not significantly correlate with the Hα emission. The high kinetic temperatures (T kin 50 K) of the dense gas traced by para-H 2 CO appear to be correlated with the embedded infrared sources inside the clouds and/or YSOs in the N113 and N159W regions. The lower temperatures (T kin < 50 K) are measured at the outskirts of the H 2 CO-bearing distributions of both N113 and N159W. It seems that the kinetic temperatures of the dense gas traced by para-H 2 CO are weakly affected by the external sources of the Hα emission. The non-thermal velocity dispersions of para-H 2 CO are well correlated with the gas kinetic temperatures in the N113 region, implying that the higher kinetic temperature traced by para-H 2 CO is related to turbulence on a ∼0.4 pc scale. The dense gas heating appears to be dominated by internal star formation activity, radiation, and/or turbulence. It seems that the mechanism heating the dense gas of the star-forming regions in the LMC is consistent with that in Galactic massive star-forming regions located in the Galactic plane.

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

Cited by 18 publications

References 166 publications

ALMA Observations of Molecular Complexity in the Large Magellanic Cloud: The N105 Star-Forming Region

ALMA Observations of Molecular Complexity in the Large Magellanic Cloud: The N105 Star-Forming Region

Chiral Selection, Isotopic Abundance Shifts, and Autocatalysis of Meteoritic Amino Acids

Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde IV. The ALMA view of N113 and N159W in the LMC

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