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We investigate general aspects of molecular line formation under conditions which are typical of prestellar cores. Focusing on simple linear molecules, we study formation of their rotational lines by radiative transfer simulations. We…

Astrophysics · Physics 2009-11-13 Ya. Pavlyuchenkov , D. Wiebe , B. Shustov , Th. Henning , R. Launhardt , D. Semenov

We review the properties of low mass dense molecular cloud cores, including starless, prestellar, and Class 0 protostellar cores, as derived from observations. In particular we discuss them in the context of the current debate surrounding…

Astrophysics · Physics 2007-05-23 D. Ward-Thompson , P. Andre , R. Crutcher , D. Johnstone , T. Onishi , C. Wilson

We present 2D Monte Carlo radiative transfer simulations of flattened prestellar cores. We argue the importance of observing prestellar cores near the peak of their emission spectra, and we point out observable characteristic features on…

Astrophysics · Physics 2007-05-23 D. Stamatellos , A. P. Whitworth

Low-mass dense cores represent the state of molecular gas associated with the earliest phases of low-mass star formation. Such cores are called "protostellar" or "starless," depending on whether they do or do not contain compact sources of…

Astrophysics · Physics 2007-05-23 J. Di Francesco , N. J. Evans , P. Caselli , P. C. Myers , Y. Shirley , A. Aikawa , M. Tafalla

Recently, a subset of starless cores whose thermal Jeans mass is apparently overwhelmed by the mass of the core has been identified, e.g., the core {\small L183}. In literature, massive cores such as this one are often referred to as…

Astrophysics of Galaxies · Physics 2013-01-03 S. Anathpindika , James Di Francesco

Starless cores represent the initial stage of evolution toward (proto)star formation, and a subset of them, known as prestellar cores, with high density (~ 10^6 cm^-3 or higher) and being centrally concentrated are expected to be embryos of…

A brief summary is presented of our current knowledge of the structure of cold molecular cloud cores that do not contain protostars, sometimes known as starless cores. The most centrally condensed starless cores are known as pre-stellar…

Astrophysics · Physics 2007-05-23 D. Ward-Thompson , D. J. Nutter , J. M. Kirk , P. Andre

We investigate the uncertainties affecting the temperature profiles of dense cores of interstellar clouds. In regions shielded from external ultraviolet radiation, the problem is reduced to the balance between cosmic ray heating, line…

Astrophysics of Galaxies · Physics 2015-05-30 M. Juvela , N. Ysard

We describe a model for the thermal and dynamical equilibrium of starless cores that includes the radiative transfer of the gas and dust and simple CO chemistry. The model shows that the structure and behavior of the cores is significantly…

Astrophysics · Physics 2009-11-13 Eric Keto , Paola Caselli

Constraining the temperature and density structure of dense molecular cloud cores is fundamental for understanding the initial conditions of star formation. We use Herschel observations of the thermal FIR dust emission from nearby isolated…

Aims: We aim to simulate radial profiles of molecular abundances and the gas temperature in cold and heavily shielded starless cores by combining chemical and radiative transfer models. Methods: A determination of the dust temperature in a…

Astrophysics of Galaxies · Physics 2015-06-05 O. Sipilä

We present results of our study on eight dense cores, previously classified as starless, using infrared (3-160 {\micron}) imaging observations with \textit{AKARI} telescope and molecular line (HCN and N$_2$H$^+$) mapping observations with…

Astrophysics of Galaxies · Physics 2016-06-22 Gwanjeong Kim , Chang Won Lee , Maheswar Gopinathan , Woong-Seob Jeong , Mi-Ryang Kim

ISO data taken with the long-wavelength imaging photo-polarimeter ISOPHOT are presented of 18 pre-stellar cores at three far-infrared wavelengths - 90, 170 and 200 microns. Most of the cores are detected clearly at 170 and 200 but only one…

Astrophysics · Physics 2009-11-07 D. Ward-Thompson , P. Andre , J. M. Kirk

Observations of dark cloud cores have been carried out in the mid-infrared using ISOCAM and in the far-infrared using ISOPHOT, both aboard the Infrared Space Observatory. The cores are in most cases detected in emission at 200 and 170…

Astrophysics · Physics 2007-05-23 Aurore Bacmann , Philippe Andre , Derek Ward-Thompson

The mass of prestellar cores is an essential ingredient to understand the onset of star formation in the core. The low level of emission from cold dust may keep parts of it hidden from observation. We aim to determine the fraction of core…

Astrophysics of Galaxies · Physics 2016-09-21 Juergen Steinacker , Hendrik Linz , Henrik Beuther , Thomas Henning , Aurore Bacmann

Since molecules are ubiquitous in space, the study of the 'Molecular Universe' could unfold the mystery of the existing Interstellar medium. Star formation is linked to the chemical evolution processes. Thus, an analysis of the formation of…

Astrophysics of Galaxies · Physics 2024-05-29 Bratati Bhat

A solar-type system starts from an initial molecular core that acquires organic complexity as it evolves. The so-called prestellar cores that can be studied are rare, which has hampered our understanding of how organic chemistry sets in and…

Improving our understanding of the initial conditions and earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We review the properties of low-mass dense…

Astrophysics · Physics 2008-01-29 Philippe André , Shantanu Basu , Shu-ichiro Inutsuka

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

We test the hypothesis that the starless cores may be gravitationally bound clouds supported largely by thermal pressure by comparing observed molecular line spectra to theoretical spectra produced by a simulation that includes…

Astrophysics · Physics 2009-11-13 Eric Keto , George Field
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