Ethyl alcohol and sugar in comet C/2014 Q2 (Lovejoy)

The presence of numerous complex organic molecules (COMs; defined as those containing six or more atoms) around protostars shows that star formation is accompanied by an increase of molecular complexity. These COMs may be part of the material from which planetesimals and, ultimately, planets formed. Comets represent some of the oldest and most primitive material in the solar system, including ices, and are thus our best window into the volatile composition of the solar protoplanetary disk. Molecules identified to be present in cometary ices include water, simple hydrocarbons, oxygen, sulfur, and nitrogen-bearing species, as well as a few COMs, such as ethylene glycol and glycine. We report the detection of 21 molecules in comet C/2014 Q2 (Lovejoy), including the first identification of ethyl alcohol (ethanol, C2H5OH) and the simplest monosaccharide sugar glycolaldehyde (CH2OHCHO) in a comet. The abundances of ethanol and glycolaldehyde, respectively 5 and 0.8% relative to methanol (0.12 and 0.02% relative to water), are somewhat higher than the values measured in solar-type protostars. Overall, the high abundance of COMs in cometary ices supports the formation through grain-surface reactions in the solar system protoplanetary disk.

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Organic molecules in protostellar environments

Proceedings of the International Astronomical Union ◽

10.1017/s174392130802125x ◽

2008 ◽

Vol 4 (S251) ◽

pp. 79-88 ◽

Cited By ~ 6

Author(s):

Cecilia Ceccarelli

Keyword(s):

Solar System ◽

Organic Molecules ◽

Planetary System ◽

Chemistry Laboratory ◽

Chemical Factory ◽

Solar Type ◽

Molecular Complexity ◽

Simple Molecules ◽

Complex Organic ◽

Collapse Phase

AbstractThe sequence that brings matter from a molecular cloud to a fully developed star plus planetary system seems to be a unique and rich chemistry laboratory where, step by step, molecular complexity increases. During the cold pre-collapse phase, atoms and simple molecules, like CO, freeze out onto the dust grains, forming icy mantles. Reactions on the grain surfaces likely form hydrogenated molecules (notably H2O, CH4, H2CO, CH3OH, and NH3) and perhaps even more complex organic molecules. The hallmark of this era is the super-deuteration phenomenon, i. e. the abnormal enhancement of molecules containing one or more D atoms instead of H atoms, by up to 13 orders of magnitude with respect to the cosmic elemental D/H ratio (~10−5). The frozen molecules are released into the gas upon warming by the forming star and undergo reactions which further increase the molecular complexity, leading to several complex organic molecules. Products of this efficient chemical factory are observed in the hot corinos, which are warm (~100 K), dense (~107–108 cm−3) solar-system-sized regions at the centre of the collapsing envelopes of solar type protostars. In this contribution, I review what is known about the organic molecules in protostellar environments, with emphasis on the hot corinos, and how possibly the organic molecules formed at this stage may constitute an heritage for the forming planetary system.

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The ALMA-PILS Survey: New insights into the complex chemistry of young stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319002849 ◽

2018 ◽

Vol 14 (S345) ◽

pp. 132-136

Author(s):

Jes K. Jørgensen ◽

Keyword(s):

Solar System ◽

Organic Molecules ◽

High Sensitivity ◽

Young Stars ◽

Early Solar System ◽

Fundamental Goal ◽

Solar Type ◽

Complex Chemistry ◽

Spectral Survey ◽

Complex Organic

AbstractUnderstanding how, when and where complex organic and potentially prebiotic molecules are formed is a fundamental goal of astrochemistry. Since its beginning the Atacama Large Millimeter/submillimeter Array (ALMA) has demonstrated its capabilities for studies of the chemistry of solar-type stars. Its high sensitivity and fine spectral and angular resolution makes it possible to study the chemistry of young stars on Solar System scales. We here present an unbiased spectral survey, Protostellar Interferometric Line Survey (PILS), of the astrochemical template source and Class 0 protostellar binary IRAS 16293-2422 using ALMA. The high quality ALMA data have allowed us to detect a wealth of species previously undetected toward solar-type protostars as well as the interstellar medium in general. Also, the data show the presence of numerous rare isotopologues of complex organic molecules and other species: the exact measurements of the abundances of the complex organic molecules and their isotopologues shed new light onto the formation of these species and provide a chemical link between the embedded protostellar stages and the early Solar System.

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Prebiologically Important Interstellar Molecules

Symposium - International Astronomical Union ◽

10.1017/s0074180900193246 ◽

2004 ◽

Vol 213 ◽

pp. 185-188

Author(s):

Y.-J. Kuan ◽

H.-C. Huang ◽

S. B. Charnley ◽

W.-L. Tseng ◽

L. E. Snyder ◽

...

Keyword(s):

Amino Acid ◽

Organic Molecules ◽

Prebiotic Chemistry ◽

Interstellar Space ◽

Central Question ◽

Dna And Rna ◽

The Galaxy ◽

Molecular Complexity ◽

Cloud Cores ◽

Complex Organic

Understanding the organic chemistry of molecular clouds, particularly the formation of biologically important molecules, is fundamental to the study of the processes which lead to the origin, evolution and distribution of life in the Galaxy. Determining the level of molecular complexity attainable in the clouds, and the nature of the complex organic material available to protostellar disks and the planetary systems that form from them, requires an understanding of the possible chemical pathways and is therefore a central question in astrochemistry. We have thus searched for prebiologically important molecules in the hot molecular cloud cores: Sgr B2(N-LMH), W51 e1/e2 and Orion-KL. Among the molecules searched: Pyrimidine is the unsubstituted ring analogue for three of the DNA and RNA bases. 2H-Azirine and Aziridine are azaheterocyclic compounds. And Glycine is the simplest amino acid. Detections of these interstellar organic molecular species will thus have important implications for Astrobiology. Our preliminary results indicate a tentative detection of interstellar glycine. If confirmed, this will be the first detection of an amino acid in interstellar space and will greatly strengthen the thesis that interstellar organic molecules could have played a pivotal role in the prebiotic chemistry of the early Earth.

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Seeds of Life in Space (SOLIS)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201937297 ◽

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.

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The role of stellar cosmic rays in protoplanetary disk evolution

10.5194/epsc2020-20 ◽

2020 ◽

Author(s):

Donna Rodgers-Lee ◽

Andrew Taylor ◽

Turlough Downes ◽

Tom Ray

Keyword(s):

Cosmic Rays ◽

Organic Molecules ◽

Protoplanetary Disks ◽

Protoplanetary Disk ◽

X Rays ◽

Solar Mass ◽

Density Profiles ◽

Disk Mass ◽

Solar Type

The role of magnetic fields in the evolution and dispersal of protoplanetary disks remains unclear to date partially due to the uncertainty regarding the sources of ionisation present in protoplanetary disks. Magnetic fields can only influence protoplanetary disk dynamics if the disks are sufficiently ionised. Ionisation due to X-rays, FUV photons and radioactivity is well-studied and generally only leads to high levels of ionisation close to the young star and in the surface layers of protoplanetary disks due to high disk column densities. Here I will instead focus on the importance of stellar cosmic rays which may provide a source of ionisation for the outer regions, and closer to the midplane, of protoplanetary disks. Young solar-type stars are very magnetically active and drive stronger stellar winds in comparison to the present day Sun. The increased magnetic activity of young solar-type stars suggests that they are efficient ~GeV particle accelerators producing so-called stellar cosmic rays. Thus, protoplanetary disks are likely to be bombarded by stellar cosmic rays, influencing their chemical and dynamic evolution. These incident particles are believed to trigger the formation of complex organic molecules. Thus, they are essential to advance our understanding of how organic molecules, the building blocks of life in the Universe, form. Recent ALMA observations have provided a number of tantalising clues as to the possible importance of stellar cosmic rays in protoplanetary disks. On the one hand, chemical modelling of observations of TW Hya&#8217;s protoplanetary disk suggest that the overall ionisation rate is remarkably low. While on the other hand, ALMA observations have been used to infer the presence of significant turbulent motion in DM Tau&#8217;s protoplanetary disk. This turbulent motion is likely driven by the magneto-rotational instability which would require a much higher level of ionisation than was inferred in TW Hya&#8217;s disk for instance. I will discuss the potential influence of stellar cosmic rays in these disks.&#160; More generally, I will present recent results which investigated the propagation, and ionising effect, of stellar cosmic rays in protoplanetary disks around young solar-mass stars. Unlike X-rays and FUV photons, stellar cosmic rays may effectively avoid being attenuated by the high column densities in the inner regions of protoplanetary disks due to their diffusive transport. To construct our disk density profiles, we use observationally inferred values from nearby star-forming regions for the total disk mass and the radial density profile. By varying the disk mass within the observed scatter for a solar-mass star, we find for a large range of disk masses and density profiles that protoplanetary disks are &#8220;optically thin&#8221; to low energy stellar cosmic rays. I will describe how our results indicate, for a wide range of disk masses, that low energy stellar cosmic rays provide an important source of ionisation at the disk midplane at large radii (&#8764;70 au). Finally, I will discuss the type of systems where we expect that stellar cosmic rays are likely to be most influential.&#160;

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Exploring molecular complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)

Astronomy and Astrophysics ◽

10.1051/0004-6361/201527268 ◽

2016 ◽

Vol 587 ◽

pp. A91 ◽

Cited By ~ 84

Author(s):

A. Belloche ◽

H. S. P. Müller ◽

R. T. Garrod ◽

K. M. Menten

Keyword(s):

Organic Molecules ◽

Molecular Complexity ◽

Complex Organic

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Carbonaceous chondrite meteorites as a record of protoplanetary disk conditions

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009177 ◽

2019 ◽

Vol 15 (S350) ◽

pp. 135-138

Author(s):

Sara S. Russell ◽

Enrica Bonato ◽

Helena Bates ◽

Ashley J. King ◽

Natasha V. Almeida ◽

...

Keyword(s):

Organic Molecules ◽

Carbonaceous Chondrite ◽

Protoplanetary Disk ◽

Parent Body ◽

Carbonaceous Chondrites ◽

Aqueous Processing ◽

Chondritic Meteorites ◽

Dust Component ◽

Key Features ◽

Complex Organic

AbstractChondritic meteorites, and especially the most volatile-rich chondrites, the carbonaceous chondrites, preserve a record of the solar protoplanetary disk dust component and how it has been changed both in the disk environment itself and in its asteroidal parent body. Here we review some of the key features of carbonaceous chondrites and report some new data on their organics component. These show that the nebula reached temperature of >10000C, but only very locally, to produce chondrules. Most meteoritic material underwent thermal and/or aqueous processing, but some retain delicate nebular components such as complex organic molecules and amorphous silicates.

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