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Related papers: Decrease of the organic deuteration during the evo…

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The recent detection of gas-phase methanol (CH$_3$OH) lines in the disc of TW Hya by Walsh et al. provided the first observational constraints on the complex O-bearing organic content in protoplanetary discs. The emission has a ring-like…

Solar and Stellar Astrophysics · Physics 2017-03-14 S. Yu. Parfenov , D. A. Semenov , Th. Henning , A. S. Shapovalova , A. M. Sobolev , R. Teague

This paper presents a detailed study of the chemistry in the outflow associated with the low-mass protostar NGC1333-IRAS2A down to 3" (650 AU) scales. Millimeter-wavelength aperture-synthesis observations from the OVRO and BIMA…

Deuterated ions are abundant in cold (T=10 K), dense (n=10^5 cm^-3) regions, in which CO is frozen out onto dust grains. In such environments, the deuterium fractionation of such ions can exceed the elemental abundance ratio of D/H by a…

Astrophysics · Physics 2009-11-13 M. Emprechtinger , P. Caselli , N. H. Volgenau , J. Stutzki , M. C. Wiedner

The Central Molecular Zone (CMZ) contains most of the mass of our Galaxy but its star formation rate is one order of magnitude lower than in the Galactic disc. This is likely related to the fact that the bulk of the gas in the CMZ is in a…

Chemical models predict that in cold cores gas-phase methanol is expected to be abundant at the outer edge of the CO depletion zone, where CO is actively adsorbed. CO adsorption correlates with volume density in cold cores, and, in nearby…

Radioastronomical observations have recently discovered PAHs of moderate size (up to 24 carbon atoms) in cold dark clouds, although it is currently unknown whether they are formed in situ through a bottom-up mechanism or from larger PAHs…

We present the spectra of Complex Organic Molecules (COMs) detected in HOPS 373SW with the Atacama Large Millimeter/submillimeter Array (ALMA). HOPS 373SW, which is a component of a protostellar binary with a separation of 1500 au, has been…

Solar and Stellar Astrophysics · Physics 2023-06-30 Jeong-Eun Lee , Giseon Baek , Seokho Lee , Jae-Hong Jeong , Chul-Hwan Kim , Yuri Aikawa , Gregory J. Herczeg , Doug Johnstone , John J. Tobin

(Abridged) The purpose of this paper is to explore and compare the physical and chemical structure of Class I low-mass protostellar sources on protoplanetary disc scales. We present a study of the dust and gas emission towards a…

High-mass stars are expected to form from dense prestellar cores. Their precise formation conditions are widely discussed, including their virial condition, which results in slow collapse for super-virial cores with strong support by…

Astrophysics of Galaxies · Physics 2017-06-21 Bastian Körtgen , Stefano Bovino , Dominik R. G. Schleicher , Andrea Giannetti , Robi Banerjee

Context: In the last years, the H2D+ and D2H+ molecules have gained great attention as probes of cold and depleted dense molecular cloud cores. These ions are at the basis of molecular deuterium fractionation, a common characteristic…

Astrophysics of Galaxies · Physics 2015-05-19 B. Parise , A. Belloche , F. Du , R. Güsten , K. M. Menten

We present maps of the 6 cm and 1.3 mm transitions of formaldehyde toward three cold, dense pre-protostellar cores: L1498, L1512, and L1544. The 6 cm transition is a unique probe of high density gas at low temperature. However, our models…

Astrophysics · Physics 2009-11-10 Kaisa E. Young , Jeong-Eun Lee , Neal J. Evans , Paul F. Goldsmith , Steven D. Doty

The standard interstellar ratio of deuterium to hydrogen (D/H) atoms is $\sim 1.5 \times 10^{-5}$. However, the deuterium fractionation is in fact found to be enhanced, to different degrees, in cold, dark cores, hot cores around massive…

Solar and Stellar Astrophysics · Physics 2015-06-19 Zainab Awad , Serena Viti , Estelle Bayet , Paola Caselli

Young massive stars are usually found embedded in dense massive molecular clumps and are known for being highly obscured and distant. During their formation process, deuteration is regarded as a potentially good indicator of the very early…

Iram 30-m Observations towards eight protostellar outflow sources were taken in the 96-\SI{176}{\giga\hertz} range. Transitions of CH$_3$OH and CH$_3$CHO were detected in seven of them. The integrated emission of the transitions of each…

Recent studies suggest that infrared dark clouds (IRDCs) have the potential of harboring the earliest stages of massive star formation and indeed evidence for this is found toward distinct regions within them. We present a study with the…

Astrophysics of Galaxies · Physics 2015-05-27 Laura Gomez , Friedrich Wyrowski , Thushara Pillai , Silvia Leurini , Karl M. Menten

We report on the detection of deuterated molecular hydrogen, HD, at $z = 0.18$. HD and H$_{\rm 2}$ are detected in HST/COS data of a low metallicity ($Z \sim 0.07Z_\odot$) damped Ly$\alpha$ system at $z = 0.18562$ toward QSO B0120$-$28,…

Astrophysics of Galaxies · Physics 2015-06-18 Cristina M. Oliveira , Kenneth R. Sembach , Jason Tumlinson , John O'Meara , Christopher Thom

The HDO/H2O ratio is a powerful diagnostic to understand the evolution of water from the first stages of star formation to the formation of planets and comets. Our aim is to determine precisely the abundance distribution of HDO towards the…

Methanol (CH$_{3}$OH) is a key complex organic molecule (COM) in the interstellar medium, widely used as a tracer of dense gas and hot molecular cores (HMCs). Using high-resolution ALMA observations from the ATOMS survey, we investigate the…

Saturn's moon Enceladus has vents emerging from a sub-surface ocean, offering unique probes into the liquid environment. These vents drain into the larger neutral torus in orbit around Saturn. We present a methanol (CH3OH) detection…

Earth and Planetary Astrophysics · Physics 2017-09-28 E. Drabek-Maunder , J. Greaves , H. J. Fraser , D. L. Clements , L. -N. Alconcel

We present ALMA maps of the starless molecular cloud core Ophiuchus/H-MM1 in the lines of deuterated ammonia (ortho-NH2D), methanol (CH3OH), and sulphur monoxide (SO). The dense core is seen in NH2D emission, whereas the CH3OH and SO…

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