scholarly journals Prevalence of Complex Organic Molecules in Starless and Prestellar Cores within the Taurus Molecular Cloud

2020 ◽  
Vol 891 (1) ◽  
pp. 73 ◽  
Author(s):  
Samantha Scibelli ◽  
Yancy Shirley
Keyword(s):  
Molecular Cloud ◽  
Organic Molecules ◽  
Prestellar Cores ◽  
Complex Organic ◽  
Taurus Molecular Cloud

scholarly journals Complex Organic Molecules in Taurus Molecular Cloud-1

2018 ◽  
Vol 854 (2) ◽  
pp. 116 ◽  
Author(s):  
Tatsuya Soma ◽  
Nami Sakai ◽  
Yoshimasa Watanabe ◽  
Satoshi Yamamoto
Keyword(s):  
Molecular Cloud ◽  
Organic Molecules ◽  
Complex Organic ◽  
Taurus Molecular Cloud

scholarly journals Fullerenes in the IC 348 star cluster of the Perseus Molecular Cloud

2019 ◽  
Author(s):  
S Iglesias-Groth
Keyword(s):  
Molecular Cloud ◽  
Organic Molecules ◽  
Protoplanetary Disks ◽  
Building Blocks ◽  
Cluster Emission ◽  
Star Forming ◽  
Available Carbon ◽  
Prebiotic Molecules ◽  
Complex Organic ◽  
Early Phases

Abstract We present the detection of fullerenes C60 and C70 in the star-forming region IC 348 of the Perseus molecular cloud. Mid-IR vibrational transitions of C60 and C70 in emission are found in Spitzer IRS spectra of individual stars (LRLL 1, 2, 58), in the averaged spectrum of three other cluster stars (LRLL 21, 31 and 67) and in spectra obtained at four interstellar locations distributed across the IC 348 region. Fullerene bands appear widely distributed in this region with higher strength in the lines-of-sight of stars at the core of the cluster. Emission features consistent with three most intense bands of the C$_{60}^+$ and with one of C$_{60}^-$ are also found in several spectra, and if ascribed to these ionized species it would imply ionization fractions at 20 and 10 %, respectively. The stars under consideration host protoplanetary disks, however the spatial resolution of the spectra is not sufficient to disentangle the presence of fullerenes in them. If fullerene abundances in the cloud were representative of IC 348 protoplanetary disks, C60, the most abundant of the two species, could host ∼ 0.1 % of the total available carbon in the disks. This should encourage dedicated searches in young disks with upcoming facilities as JWST. Fullerenes provide a reservoir of pentagonal and hexagonal carbon rings which could be important as building blocks of prebiotic molecules. Accretion of these robust molecules in early phases of planet formation may contribute to the formation of complex organic molecules in young planets.

scholarly journals Seeds of Life in Space (SOLIS)

2020 ◽  
Vol 635 ◽  
pp. A189
Author(s):  
C. Favre ◽  
C. Vastel ◽  
I. Jimenez-Serra ◽  
D. Quénard ◽  
P. Caselli ◽  
...  
Keyword(s):  
Star Formation ◽  
Organic Molecules ◽  
Physical Structure ◽  
Excitation Temperature ◽  
Gas Density ◽  
Large Program ◽  
Prestellar Cores ◽  
Solar Type ◽  
Complex Organic ◽  
Solar Type Star

Aims. The Seeds Of Life In Space IRAM/NOEMA large program aims at studying a set of crucial complex organic molecules in a sample of sources with a well-known physical structure that covers the various phases of solar-type star formation. One representative object of the transition from the prestellar core to the protostar phases has been observed toward the very low luminosity object (VeLLO) L1521F. This type of source is important to study to link prestellar cores and Class 0 sources and also to constrain the chemical evolution during the process of star formation. Methods. Two frequency windows (81.6–82.6 GHz and 96.65–97.65 GHz) were used to observe the emission from several complex organics toward the L1521F VeLLO. These setups cover transitions of ketene (H2CCO), propyne (CH3CCH), formamide (NH2CHO), methoxy (CH3O), methanol (CH3OH), dimethyl ether (CH3OCH3), and methyl formate (HCOOCH3). Results. Only two transitions of methanol (A+, E2) have been detected in the narrow window centered at 96.7 GHz (with an upper limit on E1) in a very compact emission blob (~7′′ corresponding to ~1000 au) toward the northeast of the L1521F protostar. The CS 2–1 transition is also detected within the WideX bandwidth. Consistently with what has been found in prestellar cores, the methanol emission appears ~1000 au away from the dust peak. The location of the methanol blob coincides with one of the filaments that have previously been reported in the literature. The excitation temperature of the gas inferred from methanol is (10 ± 2) K, while the H2 gas density (estimated from the detected CS 2–1 emission and previous CS 5–4 ALMA observations) is a factor >25 higher than the density in the surrounding environment (n(H2) ≥ 107 cm−3). Conclusions. Based on its compactness, low excitation temperature, and high gas density, we suggest that the methanol emission detected with NOEMA is (i) either a cold and dense shock-induced blob that formed recently (≤ a few hundred years) by infalling gas or (ii) a cold and dense fragment that may just have been formed as a result of the intense gas dynamics within the L1521F VeLLO system.

scholarly journals Complex organic molecules in the intermediate mass protostar OMC2-FIR4

2008 ◽  
Vol 4 (S251) ◽  
pp. 119-120
Author(s):  
Nicolas Crimier ◽  
Cecilia Ceccarelli ◽  
Bertrand Lefloch ◽  
Alex Faure
Keyword(s):  
Molecular Cloud ◽  
Organic Molecules ◽  
Physical Structure ◽  
Temperature Profiles ◽  
Intermediate Mass ◽  
Structure Density ◽  
Cloud Complex ◽  
Complex Organic

AbstractWe present the physical structure (density and temperature profiles) and the distribution of formaldehyde and methanol in intermediate mass protostar OMC2-FIR4 in the Orion molecular cloud complex.

THE ORIGIN OF COMPLEX ORGANIC MOLECULES IN PRESTELLAR CORES

2014 ◽  
Vol 795 (1) ◽  
pp. L2 ◽  
Author(s):  
C. Vastel ◽  
C. Ceccarelli ◽  
B. Lefloch ◽  
R. Bachiller
Keyword(s):  
Organic Molecules ◽  
Prestellar Cores ◽  
Complex Organic

scholarly journals A survey of CH2DOH towards starless and pre-stellar cores in the Taurus molecular cloud

2020 ◽  
Vol 501 (1) ◽  
pp. 347-355
Author(s):  
Hannah E Ambrose ◽  
Yancy L Shirley ◽  
Samantha Scibelli
Keyword(s):  
Gas Phase ◽  
Molecular Cloud ◽  
Organic Molecules ◽  
Dust Grains ◽  
Systematic Survey ◽  
Taurus Molecular Cloud

ABSTRACT Recent observations indicate that organic molecules are prevalent towards starless and pre-stellar cores. Deuteration of these molecules has not been well studied during the starless phase. Published observations of singly deuterated methanol, CH2DOH, have only been observed in a couple of well-studied, dense, and evolved pre-stellar cores (e.g. L1544, L183). Since the formation of gas-phase methanol during this cold phase is believed to occur via desorption from the icy grain surfaces, observations of CH2DOH may be useful as a probe of the deuterium fraction in the ice mantles of dust grains. We present a systematic survey of CH2DOH towards 12 starless and pre-stellar cores in the B10 region of the Taurus molecular cloud. Nine of the 12 cores are detected with [CH2DOH]/[CH3OH] ranging from <0.04 to 0.23$^{+0.12}_{-0.06}$ with a median value of 0.11. Sources not detected tend to have larger virial parameters and larger methanol linewidths than detected sources. The results of this survey indicate that deuterium fractionation of organic molecules, such as methanol, during the starless phase may be more easily detectable than previously thought.

scholarly journals Submillimeter-wave Observations of Complex Organic Molecules in Southern Massive Star Forming Regions

2012 ◽  
Vol 8 (S292) ◽  
pp. 107-107
Author(s):  
Kazuhisa Kamegai ◽  
Takeshi Sakai ◽  
Nami Sakai ◽  
Tomoya Hirota ◽  
Satoshi Yamamoto
Keyword(s):  
Chemical Composition ◽  
Molecular Cloud ◽  
Massive Star ◽  
Organic Molecules ◽  
Methyl Formate ◽  
Submillimeter Wave ◽  
Star Forming ◽  
Star Forming Regions ◽  
Cloud Cores ◽  
Complex Organic

AbstractSubmillimeter-wave observations of complex organic molecules toward southern massive star forming regions were carried out with ASTE 10m telescope. Methyl formate (HCOOCH3) and dimethyl ether (CH3OCH3) were detected in some molecular cloud cores with young protostars. Differences in chemical composition among neighboring cores were also found.

Imine as a Linchpin Approach for Distal C(sp2)–H Functionalization

2020 ◽  
Author(s):  
Sukdev Bag ◽  
Sadhan Jana ◽  
Sukumar Pradhan ◽  
Suman Bhowmick ◽  
Nupur Goswami ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Bond Activation ◽  
Bond Formation ◽  
Ancillary Ligand ◽  
Significant Challenge ◽  
Site Selectivity ◽  
Directing Group ◽  
Covalently Linked ◽  
Complex Organic ◽  
Post Functionalization

<p>Despite the widespread applications of C–H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing group (DG) served as an ancillary ligand to ensure proximal <i>ortho</i>-, distal <i>meta</i>- and <i>para</i>-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C–H functionalization: introduction of DG prior to C–H activation and removal of DG post-functionalization. We introduce here a transient directing group for distal C(<i>sp<sup>2</sup></i>)-H functionalization <i>via</i> reversible imine formation. By overruling facile proximal C-H bond activation by imine-<i>N</i> atom, a suitably designed pyrimidine-based transient directing group (TDG) successfully delivered selective distal C-C bond formation. Application of this transient directing group strategy for streamlining the synthesis of complex organic molecules without any necessary pre-functionalization at the distal position has been explored.</p>

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