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Related papers: Chemical Modelling of Young Stellar Objects, I. Me…

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Detailed radial/vertical structure modeling of observations of disks around Young Stellar Objects (YSOs) can provide information on the physical conditions and on the characteristics of the gas and dust in their interiors. We describe…

Astrophysics · Physics 2007-05-23 Nuria Calvet , Paola D'Alessio

We conducted observations of 12CO(J=5-4) and dust thermal continuum emission toward twenty star-forming galaxies on the main sequence at z~1.4 using ALMA to investigate the properties of the interstellar medium. The sample galaxies are…

Aims: Our aim is to determine the critical parameters in water chemistry and the contribution of water to the oxygen budget by observing and modelling water gas and ice for a sample of eleven low-mass protostars, for which both forms of…

Astrophysics of Galaxies · Physics 2014-12-03 M. Schmalzl , R. Visser , C. Walsh , T. Albertsson , E. F. van Dishoeck , L. E. Kristensen , J. C. Mottram

We use the Atacama Large sub/Millimetre Array (ALMA) to efficiently observe spectral lines across Bands 3, 4, 5, 6, 7, and 8 at high-resolution (0.5" - 0.1") for 16 bright southern Herschel sources at $1.5 < z < 4.2$. With only six and a…

Chemical abundance determinations from stellar spectra are challenged by observational noise, limitations in stellar models, and departures from simplifying assumptions. While traditional and supervised machine learning methods have made…

Solar and Stellar Astrophysics · Physics 2025-12-24 Theosamuele Signor , Paula Jofré , Hernan Lira , Sara Vitali , Luis Martí , Nayat Sánchez-Pi

We aim to understand the rich chemical composition of AFGL 2591, a prototypical isolated high-mass star-forming region. Based on HIFI and JCMT data, the molecular abundances of species found in the protostellar envelope of AFGL 2591 were…

In the context of the concordance cosmology, structure formation in the Universe is the result of the amplification, by gravitational effects, of small perturbations in the primeval density field. This results in the formation of structures…

Astrophysics of Galaxies · Physics 2021-06-11 L. Biaus , C. Scannapieco , S. E. Nuza

Understanding the gas abundance distribution is essential when tracing star formation using molecular line observations. Changing density and temperature conditions cause gas to freeze-out onto dust grains, and this needs to be taken into…

Astrophysics · Physics 2009-11-13 C. Brinch , R. J. van Weeren , M. R. Hogerheijde

Complex organic molecules (COMs) are known to be abundant toward some low-mass young stellar objects (YSOs), but how these detections relate to typical COM abundance are not yet understood. We aim to constrain the frequency distribution of…

Astrophysics of Galaxies · Physics 2015-06-19 Karin I. Oberg , Trish Lauck , Dawn Graninger

The investigation of star forming regions have enormously benefited from the recent advent of the ALMA interferometer. More specifically, the unprecedented combination of high-sensitivity and high-angular resolution provided by ALMA allows…

We present the chemical abundance analysis of 19 upper main-sequence stars of the young open cluster NGC 6250 (log t ~ 7.42 yr). This work is part of a project aimed at setting observational constraints on the theory of atomic diffusion in…

Solar and Stellar Astrophysics · Physics 2017-01-18 A. J. Martin , M. J. Stift , L. Fossati , S. Bagnulo , C. Scalia , F. Leone , B. Smalley

In previous works, we have investigated the star-forming region G29.96$-$0.02 where the massive young stellar object (MYSO) G29.862$-$0.0044 (hereafter G29) is embedded in a hot molecular core. In one of them, of multiwavelength nature,…

Astrophysics of Galaxies · Physics 2024-06-05 N. C. Martinez , S. Paron , D. Mast , M. E. Ortega , A. Petriella , C. Fariña

(abridged) The far-UV wavelength range (912-2000A) provides access to atomic and molecular transitions of many species the interstellar medium (ISM), circumgalactic medium (CGM), and intergalactic medium, within phases spanning a wide range…

Aims: To calculate chemistry and gas temperature of evolving protoplanetary disks with decreasing mass or dust settling, and to explore the sensitivity of gas-phase tracers. Methods: The density and dust temperature profiles for a range of…

Astrophysics · Physics 2009-11-11 B. Jonkheid , C. P. Dullemond , M. R. Hogerheijde , E. F. van Dishoeck

The chemical composition of diffuse interstellar clouds is not fully established. They host an active chemistry despite their relatively low density and the ubiquitous presence of far-UV radiation. To further explore the chemical…

Astrophysics of Galaxies · Physics 2025-11-21 Maryvonne Gerin , Harvey Liszt , Belen Tercero , Jose Cernicharo

(Abridged) We explore the chemistry of the most abundant C, O, S, and N bearing species in molecular clouds, in the context of the IRAM 30 m Large Programme Gas phase Elemental abundances in Molecular Clouds (GEMS). In this work, we aim to…

Filamentary molecular clouds are an essential intermediate stage in the star formation process. To test whether these structures are universal throughout cosmic star formation history, it is crucial to study low-metallicity environments…

(Abridged) Aims: We aim to use the progressive heating of the gas caused by the feedback of high-mass young stellar objects (YSOs) to prove the statistical validity of the most common schemes used to define an evolutionary sequence for…

Astrophysics of Galaxies · Physics 2017-07-05 A. Giannetti , S. Leurini , F. Wyrowski , J. Urquhart , T. Csengeri , K. M. Menten , C. König , R. Güsten

Understanding the chemical evolution in star-forming cores is a necessary pre-condition to correctly assess physical conditions when using molecular emission. We follow the evolution of chemistry and molecular line profiles through the…

Astrophysics · Physics 2009-11-10 Jeong-Eun Lee , Edwin A. Bergin , Neal J. Evans

We report on the observation of hot water vapor (steam) in the inner AU of a young massive star located in the star-forming region IRAS 08576-4334. The water lines are detected in a medium resolution (R=10,000) K-band spectrum taken by the…

Astrophysics · Physics 2009-11-10 W. -F. Thi , A. Bik
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