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相关论文: Tracing the sulfur depletion in starless and pre-s…

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Dense low mass cores in nearby clouds like Taurus and Auriga are some of the simplest sites currently forming stars like our Sun. Because of their simplicity and proximity, dense cores offer the clearest view of the different phases of star…

天体物理学 · 物理学 2017-03-08 Mario Tafalla

High resolution UVES spectra of 40 main-sequence stars with -3.3 < [Fe/H] < -1.0 are used to derive S, Fe and Zn abundances from lines in the 400 - 950 nm region. For one star we also present novel observations of the SI triplet at 1.046…

天体物理学 · 物理学 2009-11-13 P. E. Nissen , C. Akerman , M. Asplund , D. Fabbian , F. Kerber , H. U. Kaufl , M. Pettini

Sulfur abundances have been determined for ten stars to resolve a debate in the literature on the Galactic chemical evolution of sulfur in the halo phase of the Milky Way. Our analysis is based on observations of the S I lines at 9212.9,…

天体物理学 · 物理学 2009-11-10 N. Ryde , D. L. Lambert

(Abridged) We present evidence that low-mass starless cores, the simplest units of star formation, are systematically differentiated in their chemical composition. Molecules including CO and CS almost vanish near the core centers, where the…

天体物理学 · 物理学 2008-11-26 M. Tafalla , P. C. Myers , P. Caselli , C. M. Walmsley , C. Comito

This work aims to study the unexplained sulfur depletion observed toward dense clouds and protostars. We made simulation experiments of the UV-photoprocessing and sublimation of H2S and H2S:H2O ice in dense clouds and circumstellar regions,…

地球与行星天体物理 · 物理学 2015-06-03 A. Jiménez-Escobar , G. M. Muñoz Caro

We aim to investigate the chemistry and gas phase abundance of HNCO and the variation of the HNCO/CS abundance ratio as a diagnostic of the physics and chemistry in regions of massive star formation. A numerical-chemical model has been…

星系天体物理 · 物理学 2015-05-14 D. M. Tideswell , G. A. Fuller , T. J. Millar , A. J. Markwick

The sulphur chemistry in nine regions in the earliest stages of high-mass star formation is studied through single-dish submillimeter spectroscopy. The line profiles indicate that 10-50% of the SO and SO2 emission arises in high-velocity…

天体物理学 · 物理学 2009-11-10 F. F. S. van der Tak , A. M. S. Boonman , R. Braakman , E. F. van Dishoeck

The nature and abundance of sulfur chemistry in protoplanetary disks (PPDs) may impact the sulfur inventory on young planets and therefore their habitability. PPDs also present an interesting test bed for sulfur chemistry models, since each…

星系天体物理 · 物理学 2019-05-15 Romane Le Gal , Karin I. Öberg , Ryan Loomis , Jamila Pegues , Jennifer B. Bergner

Context. The measurement of $\alpha$-elements abundances provides a powerful tool to put constraints on chemical evolution and star formation history of galaxies. The majority of studies on the $\alpha$-element Sulfur (S) are focused on…

星系天体物理 · 物理学 2021-12-22 F. Lucertini , L. Monaco , E. Caffau , P. Bonifacio , A. Mucciarelli

Sulphur depletion in the interstellar medium (ISM) is a long-standing issue, as only 1% of its cosmic abundance is detected in dense molecular clouds (MCs), while it does not appear to be depleted in other environments. In addition to gas…

星系天体物理 · 物理学 2024-01-22 Jessica Perrero , Leire Beitia-Antero , Asunción Fuente , Piero Ugliengo , Albert Rimola

We present the results of a single-pointing survey of 207 dense cores embedded in Planck Galactic Cold Clumps distributed in five different environments ($\lambda$ Orionis, Orion A, B, Galactic plane, and high latitudes) to identify dense…

We have performed new determinations of sulphur and silicon abundances for a sample of 26 disk stars based on high-resolution, high signal-to-noise spectra. The results indicate a solar [S/Fe] for [Fe/H] >-0.3, below which [S/Fe] increases…

天体物理学 · 物理学 2009-11-07 Y. Q. Chen , P. E. Nissen , G. Zhao , M. Asplund

We study the content in S-bearing molecules of protoplanetary disks around low-mass stars. We used the new IRAM 30-m receiver EMIR to perform simultaneous observations of the $1_{10}-1_{01}$ line of H$_2$S at 168.8 GHz and $2_{23}-1_{12}$…

We present the chemistry, temperature, and dynamical state of a sample of 193 dense cores or core candidates in the Perseus Molecular cloud and compare the properties of cores associated with young stars and clusters with those which are…

We report observations of the expected main S-bearing species (SO, SO2 and H2S) in the low-mass star forming region L1689N. We obtained large scale (~300''x200'') maps of several transitions from these molecules with the goal to study the…

天体物理学 · 物理学 2007-05-23 V. Wakelam , A. Castets , C. Ceccarelli , B. Lefloch , E. Caux , L. Pagani

H2S is thought to be the main sulphur reservoir in the ice, being therefore a key molecule to understand sulphur chemistry in the star formation process and to solve the missing sulphur problem. The H2S deuterium fraction can be used to…

Aims. Our goal is to complete the inventory of S-bearing molecules and their abundances in the prototypical photodissociation region (PDR) the Horsehead nebula to gain insight into sulphur chemistry in UV irradiated regions. Based on the…

Starless molecular cores are natural laboratories for interstellar molecular chemistry research. The chemistry of ices in such objects was investigated with a three-phase (gas, surface, and mantle) model. We considered the center part of…

星系天体物理 · 物理学 2015-04-24 Juris Kalvans

We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores, and explore the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of…

星系天体物理 · 物理学 2015-06-03 Konstantinos Tassis , Karen Willacy , Harold W. Yorke , Neal J. Turner

Sulfur is important: the site of its formation is uncertain, and at very low metallicity the trend of [S/Fe] against [Fe/H] is controversial. Below [Fe/H]=-2.0, [S/Fe] remains constant or it decreases with [Fe/H], depending on the author…