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Related papers: The structure and stability of molecular cloud cor…

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In many clusters of galaxies there is evidence for cooling flows in the central regions. The ultimate fate of the gas which cools is still unknown. A possibility is that a fraction of the gas forms cold molecular clouds. We investigate the…

Astrophysics · Physics 2008-11-26 D. Puy , L. Grenacher , P. Jetzer

Based on the 850 $\mu$m dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the $\lambda$ Orionis cloud to those of PGCCs in the Orion A and B…

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

A model is presented which calculates the gas temperature and chemistry in the surface layers of flaring circumstellar disks using a code developed for photon-dominated regions. Special attention is given to the influence of dust settling.…

Astrophysics · Physics 2009-11-10 B. Jonkheid , F. G. A. Faas , G. -J. van Zadelhoff , E. F. van Dishoeck

We investigate the structure of accretion disks around massive protostar applying steady state models of thin disks. The thin disk equations are solved with proper opacities for dust and gas taking into account the huge temperature…

Solar and Stellar Astrophysics · Physics 2009-08-17 B. Vaidya , C. Fendt , H. Beuther

We present APEX 218 GHz observations of molecular emission in a complete sample of embedded protostars in the Ophiuchus star-forming region. To study the physical properties of the cores, we calculate H$_2$CO and c-C$_3$H$_2$ rotational…

Solar and Stellar Astrophysics · Physics 2017-01-25 Johan E. Lindberg , Steven B. Charnley , Jes K. Jørgensen , Martin A. Cordiner , Per Bjerkeli

Rings and gaps are ubiquitous in protoplanetary disks. Larger dust grains will concentrate in gaseous rings more compactly due to stronger aerodynamic drag. However, the effects of dust concentration on the ring's thermal structure have not…

Earth and Planetary Astrophysics · Physics 2021-12-22 Shangjia Zhang , Xiao Hu , Zhaohuan Zhu , Jaehan Bae

With Planck and Herschel, we now have the spectral coverage and angular resolution required to observe dense and cold molecular clouds. As these clouds are optically thick at short wavelength but optically thin at long wavelength, it is…

In a molecular cloud dust opacity typically dominates over gas opacity, yet in the vicinities of forming stars dust is depleted, and gas is the sole provider of opacity. In the optically thin circumstellar environments the radiation…

Solar and Stellar Astrophysics · Physics 2014-09-05 M. G. Malygin , R. Kuiper , H. Klahr , C. P. Dullemond , Th. Henning

We study effect of magnetic field on massive dense core formation in colliding unequal molecular clouds by performing magnetohydrodynamic simulations with sub-parsec resolution (0.015 pc) that can resolve the molecular cores. Initial clouds…

Astrophysics of Galaxies · Physics 2020-07-23 Nirmit Sakre , Asao Habe , Alex R. Pettitt , Takashi Okamoto

Sun-like stars form from the contraction of cold and dense interstellar clouds. How the collapse proceeds and what are the main physical processes driving it, however, is still under debate and a final consensus on the timescale of the…

We perform a virial analysis of starless dense cores in three nearby star-forming regions : L1688 in Ophiuchus, NGC 1333 in Perseus, and B18 in Taurus. Our analysis takes advantage of comprehensive kinematic information for the dense gas in…

We mapped the kinetic temperature structure of the Orion molecular cloud 1 with para-H2CO(303-202, 322-221, and 321-220) using the APEX 12m telescope. This is compared with the temperatures derived from the ratio of the NH3(2,2)/(1,1)…

Astrophysics of Galaxies · Physics 2017-12-27 X. D. Tang , C. Henkel , K. M. Menten , F. Wyrowski , N. Brinkmann , X. W. Zheng , Y. Gong , Y. X. Lin , J. Esimbek , J. J. Zhou , Y. Yuan , D. L. Li , Y. X. He

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 have retrieved Spitzer archive data of pre-stellar cores taken with the Multiband Imaging Photometer for Spitzer (MIPS) at a wavelength of 160 um. Seventeen images, containing eighteen cores, were constructed. Flux densities were…

Astrophysics · Physics 2008-11-26 J. M. Kirk , D. Ward-Thompson , P. Andre

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…

Astrophysics of Galaxies · Physics 2015-06-03 Konstantinos Tassis , Karen Willacy , Harold W. Yorke , Neal J. Turner

Ice is ubiquitous in the interstellar medium. We model the formation of the main constituents of interstellar ices, including H2O, CO2 , CO, and CH3 OH. We strive to understand what physical or chemical parameters influence the final…

Astrophysics of Galaxies · Physics 2023-07-26 A. Clément , A. Taillard , V. Wakelam , P. Gratier , J. -C. Loison , E. Dartois , F. Dulieu , J. A. Noble , M. Chabot

The connection between dense gas cores and their infant protostars is key to understanding how stars form in molecular clouds. In this paper we investigate the properties, persistence, and protostellar content of cores that would be…

Understanding the processes occurring in the nuclear disk of our Galaxy is interesting in its own right, as part of the Milky Way Galaxy, but also because it is the closest galactic nucleus. It has been more than two decades since it was…

Astrophysics · Physics 2009-11-13 F. Yusef-Zadeh , M. Wardle , S. Roy

We present a high-resolution $1.5"$ observational study towards two massive dust-and-gas cores, ORI8nw\_2 and ORI2\_6 in Orion Molecular Cloud using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). In both regions the…

Solar and Stellar Astrophysics · Physics 2015-06-16 Zhiyuan Ren , Di Li , Nicholas Chapman