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We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless to Class I. Our results show that the density structure of all but one observed cores can be modeled with a single power law rho \propto…

Solar and Stellar Astrophysics · Physics 2014-11-20 Chao-Ling Hung , Shih-Ping Lai , Chi-Hung Yan

Star formation is a series of mass assembly processes and starless cores, those cold and dense condensations in molecular clouds, play a pivotal role as initial seeds of stars. With only a limited sample of known starless cores, however,…

Chemical diversity of the gas in low-mass protostellar cores is widely recognized. In order to explore its origin, a survey of chemical composition toward 36 Class 0/I protostars in the Perseus molecular cloud complex, which are selected in…

We have compared molecular line emission to dust continuum emission and modeled molecular lines using Monte Carlo simulations in order to study the depletion of molecules and the ionization fraction in three preprotostellar cores, L1512,…

Astrophysics · Physics 2009-11-07 Jeong-Eun Lee , Neal J. Evans , Yancy L. Shirley , Ken'ichi Tatematsu

We investigated the chemical evolutions of gas phase and grain surface species across the Taurus molecular cloud-1 (TMC-1) filament from translucent phase to dense phase. By comparing observations with modeling results from an up-to-date…

Astrophysics of Galaxies · Physics 2022-04-11 Long-Fei Chen , Di Li , Donghui Quan , Xia Zhang , Qiang Chang , Xiaohu Li , Lin Xiao

Cha-MMS1 was mapped in the NH_3(1,1) line and the 1.2 cm continuum using the Australia Telescope Compact Array, ATCA. The angular resolution of the ATCA observations is 7'' (~ 1000 AU), and the velocity resolution is 50 m s^{-1}. The core…

Astrophysics of Galaxies · Physics 2017-05-26 M. S. Väisälä , J. Harju , M. J. Mantere , O. Miettinen , R. S. Sault , C. M. Walmsley , J. B. Whiteoak

We present the first comprehensive study on physical and chemical properties of quiescent starless cores L1495B and L1521B, which are known to be rich in carbon-chain molecules like the cyanopolyyne peak of TMC-1 and L1521E. We have…

Astrophysics · Physics 2009-11-10 Tomoya Hirota , Hiroyuki Maezawa , Satoshi Yamamoto

The main sulfur-bearing molecules OCS, H2S, SO, SO2, and CS have been observed in four high mass dense cores (W43-MM1, IRAS 18264, IRAS 05358, and IRAS 18162). Our goal is to put some constraints on the relative evolutionary stage of these…

Astrophysics of Galaxies · Physics 2015-05-27 V. Wakelam , F. Hersant , F. Herpin

The chemical inventory of planets is determined by the physical and chemical processes that govern the early phases of star formation. The aim is to investigate N-bearing complex organic molecules towards two Class 0 protostars (B1-c and…

Two families of models compete to explain the formation of high-mass stars. The quasi-static models predict the existence of high-mass pre-stellar cores sustained by a high degree of turbulence while competitive accretion models predict…

Astrophysics of Galaxies · Physics 2019-02-13 F. Louvet , S. Neupane , G. Garay , D. Russeil , A. Zavagno , A. Guzman , L. Gomez , L. Bronfman , T. Nony

We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find…

The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…

Astrophysics · Physics 2009-11-06 Emanuele Ripamonti , Francesco Haardt , Andrea Ferrara , Monica Colpi

We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation. We made a high-resolution column density map…

Spectral line survey observations of 7 molecular clouds in the Large Magellanic Cloud (LMC) have been conducted in the 3 mm band with the Mopra 22 m telescope to reveal chemical compositions in low metallicity conditions. Spectral lines of…

Pre-stellar cores represent the earliest stage of the star- and planet-formation process. By characterizing the physical and chemical structure of these cores we can establish the initial conditions for star and planet formation and…

Astrophysics of Galaxies · Physics 2023-07-05 S. S. Jensen , S. Spezzano , P. Caselli , T. Grassi , T. Haugbølle

In this study, the main goal is to understand the molecular cloud core collapse through the stages of first and second hydrostatic core formation. We investigate the properties of Larson's first and second cores following the evolution of…

Solar and Stellar Astrophysics · Physics 2018-10-24 Asmita Bhandare , Rolf Kuiper , Thomas Henning , Christian Fendt , Gabriel-Dominique Marleau , Anders Kölligan

We study molecular emission in a massive condensation at the border of the HII region RCW 120, paying particular attention to the Core 1 and Core 2 objects, the most massive fragments of the condensation found previously by ALMA. The latter…

Astrophysics of Galaxies · Physics 2021-03-03 M. S. Kirsanova , S. V. Salii , S. V. Kalenskii , D. S. Wiebe , A. M. Sobolev , P. A. Boley

To complement the optical absorption-line survey of diffuse molecular gas in Paper I, we obtained and analyzed far ultraviolet H$_2$ and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column…

Astrophysics · Physics 2009-11-13 K. Pan , S. R. Federman , Y. Sheffer , B. -G. Andersson

We present a comparative study of several molecular lines and of the dust contiunuum at 1.2mm in a pre-stellar core that is embedded in the Galactic cirrus cloud MCLD123.5+24.9. Previous studies found that the core is gravitationally stable…

Astrophysics · Physics 2009-11-13 Andreas Heithausen , Christoph Boettner , Fabian Walter

W43-MM1 is a young region, very rich in terms of high-mass star formation. We aim to systematically identify the massive cores which contain a hot core and compare their molecular composition. We used ALMA high-spatial resolution (2500 au)…