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

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We study the thermal equilibrium and stability of isobaric, spherical structures having a radiation source located at its center. The thermal conduction coefficient, external heating and cooling rates are represented as power laws of the…

Astrophysics · Physics 2009-06-23 Nestor Sanchez , Eugenio Lopez

The maximum temperature and radial temperature profile in a protoplanetary disc are important for the condensation of different elements in the disc. We simulate the evolution of a set of protoplanetary discs from the collapse of their…

Earth and Planetary Astrophysics · Physics 2022-01-19 Min Li , Shichun Huang , Zhaohuan Zhu , Michail I. Petaev , Jason H. Steffen

We present hydrostatic equilibrium models of spherical, self-gravitating clouds of helium and molecular hydrogen, focusing on the cold, high-density regime where solid- or liquid-hydrogen can form. The resulting structures have masses from…

Astrophysics of Galaxies · Physics 2019-08-21 Mark Walker , Mark Wardle

We analytically derive the expressions for the structure of the inner region of protoplanetary disks based on the results from the recent hydrodynamical simulations. The inner part of a disk can be divided into four regions: dust-free…

Earth and Planetary Astrophysics · Physics 2017-07-19 Takahiro Ueda , Satoshi Okuzumi , Mario Flock

We study quasi-static atmospheres of accreting protoplanetary cores for different opacity behaviors and realistic planetesimal accretion rates in various parts of protoplanetary nebula. Atmospheres segregate into those having outer…

Astrophysics · Physics 2008-11-26 Roman Rafikov

We have characterized the physical structure and chemical composition of two close-to-round starless cores in Taurus-Auriga, L1498 and L1517B. Our analysis is based on high angular resolution observations in at least two transitions of NH3,…

Astrophysics · Physics 2009-11-10 M. Tafalla , P. C. Myers , P. Caselli , C. M. Walmsley

To evaluate the effect of turbulent heating in the thermal balance of interstellar clouds, we develop an extension of the log-Poisson intermittency model to supersonic turbulence. The model depends on a parameter, d, interpreted as the…

Astrophysics · Physics 2011-02-11 Liubin Pan , Paolo Padoan

In order to understand the collapse dynamics of observed low-mass starless cores, we revise the conventional stability condition of hydrostatic Bonnor-Ebert spheres to take internal motions into account. Because observed starless cores…

Astrophysics of Galaxies · Physics 2015-06-15 Young Min Seo , Seung Soo Hong , Yancy L. Shirley

The gravitational collapse of a spherical cloud core is investigated by numerical calculations. The initial conditions of the core lie close to the critical Bonnor-Ebert sphere with a central density of \sim 10^4 cm^{-3} in one model…

Astrophysics · Physics 2009-11-10 Yuri Aikawa , Eric Herbst , Helen Roberts , Paola Caselli

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

In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many periods. The predicted column density…

Astrophysics · Physics 2008-04-14 Avery E. Broderick , Ramesh Narayan , Eric Keto , Charles J. Lada

Cold ($\sim$10 K) and dense ($\sim$10$^{5}$ cm$^{-3}$) cores of gas and dust within molecular clouds, known as starless and dynamically evolved prestellar cores, are the birthplaces of low-mass ($M$ $\leq$ few M$_\odot$) stars. As…

Astrophysics of Galaxies · Physics 2024-08-22 Samantha Scibelli , Yancy Shirley , Andrés Megías , Izaskun Jiménez-Serra

The temperature and density structure of molecular cloud cores are the most important physical quantities that determine the course of the protostellar collapse and the properties of the stars they form. Nevertheless, density profiles often…

We examine the linear stability and nonlinear growth of the thermal instability in isobarically contracting gas with various metallicities and FUV field strengths. When the H2 cooling is suppressed by FUV fields (G_0>10^-3) or the…

Astrophysics of Galaxies · Physics 2015-05-27 Tsuyoshi Inoue , Kazuyuki Omukai

We formulate the problem of the formation and collapse of nonaxisymmetric protostellar cores in weakly ionized, self-gravitating, magnetic molecular clouds. In our formulation, molecular clouds are approximated as isothermal, thin (but with…

Astrophysics · Physics 2011-02-11 Glenn E. Ciolek , Shantanu Basu

We investigate ionization and heating of gas in the dense, shielded clumps/cores of molecular clouds bathed by an influx of energetic, charged cosmic rays (CRs). These molecular clouds have complex structures, with substantial variation in…

Astrophysics of Galaxies · Physics 2021-06-02 Ellis R. Owen , Alvina Y. L. On , Shih-Ping Lai , Kinwah Wu

Cores and filamentary structures are the prime birthplaces of stars, and play key roles in the process of star formation. Latest advances in the methods of multi-scale source and filament extraction, and in making high-resolution column…

Astrophysics of Galaxies · Physics 2022-05-04 Chang Zhang , Guo-Yin Zhang , Jin-Zeng Li , Xue-Mei Li

We present a detailed model for the thermal balance, chemistry, and radiative transfer within quiescent dense molecular cloud cores that contain a central protostar. Large variations in the gas temperature are expected to affect the…

Astrophysics · Physics 2009-10-30 S. D. Doty , D. A. Neufeld

We have performed a 1 square degree 1.2mm dust continuum survey in the rho Oph molecular cloud. We detect a number of previously unknown sources, ranging from extended cores over compact, starless cores to envelopes surrounding young…

Astrophysics · Physics 2009-11-11 Thomas Stanke , Michael D. Smith , Roland Gredel , Tigran Khanzadyan

We present SMA and CARMA continuum and spectral line observations of five dense cores located in the Perseus and Ophiuchus molecular clouds whose masses exceed their thermal Jeans masses. Three of these cores have previously been identified…

Solar and Stellar Astrophysics · Physics 2015-06-05 Scott Schnee , Sarah Sadavoy , James Di Francesco , Doug Johnstone , Lisa Wei