Complex organic molecules tracing the comet-forming zones in protoplanetary disks

2019 ◽  
Vol 15 (S350) ◽  
pp. 463-464
Author(s):  
Catherine Walsh ◽  
John D. Ilee
Keyword(s):  
Gas Phase ◽  
Column Density ◽  
Organic Molecules ◽  
Rotational Temperature ◽  
Protoplanetary Disks ◽  
Independent Determination ◽  
Model Independent ◽  
Abundance And Distribution ◽  
Complex Organic

AbstractResolved emission from gas-phase methanol can reveal the abundance and distribution of the comet-forming ice reservoir in protoplanetary disks. ALMA Cycle 4 observations of four transitions of gas-phase methanol in TW Hya allow the first model-independent determination of the rotational temperature of methanol in a prototoplanetary disk. The data confirm that the methanol is rotationally cold (Trot < 50 K), and well constrain the column density to 2 × 1012 cm−2. Astrochemical models will constrain the chemical origin of methanol in TW Hya.

scholarly journals Laboratory data in support of JWST observations of interstellar ices

2019 ◽  
Vol 15 (S350) ◽  
pp. 420-421
Author(s):  
Marina G. Rachid ◽  
Jeroen Terwisscha van Scheltinga ◽  
Daniël Koletzki ◽  
Giulia Marcandalli ◽  
Ewine F. van Dishoeck ◽  
...  
Keyword(s):  
Solid State ◽  
Gas Phase ◽  
Organic Molecules ◽  
Methyl Formate ◽  
Laboratory Data ◽  
Protoplanetary Disks ◽  
Theoretical Studies ◽  
James Webb Space Telescope ◽  
Complex Organic ◽  
Experimental And Theoretical Studies

AbstractExperimental and theoretical studies have shown that Complex Organic Molecules (COMs) can be formed on icy dusty grains in molecular clouds and protoplanetary disks. The number of astronomical detections of solid COMs, however, is very limited. With the upcoming launch of the James Webb Space Telescope (JWST) this should change, but in order to identify solid state features of COMs, accurate laboratory data are needed. Here we present high resolution (0.5 cm–1) infrared ice spectra of acetone (C3H6O) and methyl formate (HCOOCH3), two molecules already identified in astronomical gas phase surveys, whose interstellar synthesis is expected to follow solid state pathways.

scholarly journals Laboratory constraints on ice formation, restructuring and desorption

2015 ◽  
Vol 11 (A29A) ◽  
pp. 309-312
Author(s):  
Karin I. Öberg
Keyword(s):  
Gas Phase ◽  
Chemical Reactions ◽  
Organic Molecules ◽  
Protoplanetary Disks ◽  
Ice Formation ◽  
Circumstellar Dust ◽  
Dust Grains ◽  
Complex Molecules ◽  
Detailed Understanding ◽  
Complex Organic

AbstractIces form on the surfaces of interstellar and circumstellar dust grains though freeze-out of molecules and atoms from the gas-phase followed by chemical reactions. The composition, chemistry, structure and desorption properties of these ices regulate two important aspects of planet formation: the locations of major condensation fronts in protoplanetary disks (i.e. snow lines) and the formation efficiencies of complex organic molecules in astrophysical environments. The latter regulates the availability of prebiotic material on nascent planets. With ALMA it is possible to directly observe both (CO) snowlines and complex organics in protoplanetary disks. The interpretation of these observations requires a detailed understanding of the fundamental ice processes that regulate the build-up, evolution and desorption of icy grain mantles. This proceeding reviews how experiments on thermal CO and N2 ice desorption, UV photodesorption of CO ice, and CO diffusion in H2O ice have been used to guide and interpret astrochemical observations of snowlines and complex molecules.

scholarly journals X-ray processing of a realistic ice mantle can explain the gas abundances in protoplanetary disks

2020 ◽  
Vol 117 (28) ◽  
pp. 16149-16153
Author(s):  
Angela Ciaravella ◽  
Guillermo M. Muñoz Caro ◽  
Antonio Jiménez-Escobar ◽  
Cesare Cecchi-Pestellini ◽  
Li-Chieh Hsiao ◽  
...  
Keyword(s):  
Gas Phase ◽  
Organic Molecules ◽  
Protoplanetary Disks ◽  
Abundant Species ◽  
X Rays ◽  
X Ray ◽  
Solar Systems ◽  
Detailed Observation ◽  
Solar Type ◽  
Complex Organic

The Atacama Large Millimeter Array has allowed a detailed observation of molecules in protoplanetary disks, which can evolve toward solar systems like our own. While CO,CO2, HCO, andH2COare often abundant species in the cold zones of the disk,CH3OHorCH3CNare only found in a few regions, and more-complex organic molecules are not observed. We simulate, experimentally, ice processing in disks under realistic conditions, that is, layered ices irradiated by soft X-rays. X-ray emission from young solar-type stars is thousands of times brighter than that of today’s sun. The ice mantle is composed of aH2O:CH4:NH3mixture, covered by a layer made ofCH3OHand CO. The photoproducts found desorbing from both ice layers to the gas phase during the irradiation converge with those detected in higher abundances in the gas phase of protoplanetary disks, providing important insights on the nonthermal processes that drive the chemistry in these objects.

scholarly journals Model-Independent Determination of the Spin of the Ω− and Its Polarization Alignment in ψ(3686)→Ω−Ω¯+

2021 ◽  
Vol 126 (9) ◽  
Author(s):  
M. Ablikim ◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
M. Albrecht ◽  
...  
Keyword(s):  
Independent Determination ◽  
Model Independent

Model independent determination of GEn from the reaction

1988 ◽  
Vol 206 (2) ◽  
pp. 187-189 ◽  
Author(s):  
E.L. Tomusiak ◽  
H. Arenhövel
Keyword(s):  
Independent Determination ◽  
Model Independent

Model-independent determination of the degree of charge transfer in molecular and metal complexes

2015 ◽  
Vol 51 (81) ◽  
pp. 15071-15074 ◽  
Author(s):  
Bora Joo ◽  
Eung-Gun Kim
Keyword(s):  
Charge Transfer ◽  
Metal Complexes ◽  
Active Space ◽  
Model Free ◽  
Independent Determination ◽  
Charge Analysis ◽  
Model Independent ◽  
Degree Of Charge Transfer

Choosing a small active space of electrons for charge analysis allows the model-free determination of the degree of charge transfer.

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.

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