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We discuss the lifetimes and evolution of clumps and cores formed as turbulent density fluctuations in nearly isothermal molecular clouds. In the non-magnetic case, clumps are unlikely to reach a hydrostatic state, and instead are expected…

High-latitude ($|b|>30^{\circ}$) molecular clouds have virial parameters that exceed 1, but whether these clouds can form stars has not been studied systematically. Using JCMT SCUBA-2 archival data, we surveyed 70 fields that target…

White dwarfs are stellar embers depleted of nuclear energy sources that cool over billions of years. These stars, which are supported by electron degeneracy pressure, reach densities of 1e7 grams per cubic centimetre in their cores. It has…

We investigate the process of metal-free star formation in the first galaxies with a high-resolution cosmological simulation. We consider the cosmologically motivated scenario in which a strong molecule-destroying Lyman-Werner (LW)…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-28 Chalence Safranek-Shrader , Meghann Agarwal , Christoph Federrath , Anshu Dubey , Milos Milosavljevic , Volker Bromm

Planck Galactic Cold Clumps (PGCCs) possibly represent the early stages of star formation. To understand better the properties of PGCCs, we studied 16 PGCCs in the L1495 cloud with molecular lines and continuum data from Herschel,…

Star formation occurs within dense regions of giant molecular clouds (GMCs), however, exactly how gas collects and evolves to form individual stars and what role dense cores play remains unclear. We use the Lagrangian cell information in…

Astrophysics of Galaxies · Physics 2026-04-09 Ananya Kaalva , Stella S. R. Offner , Nina Filippova , Michael Y. Grudic

We used the NRAO Very Large Array to search for 3.6 cm continuum emission from embedded protostars in a sample of 8 nearby ``starless'' cores that show spectroscopic evidence for infalling motions in molecular emission lines. We detect a…

Astrophysics · Physics 2009-11-07 D. W. A. Harvey , D. J. Wilner , J. Di Francesco , C. -W. Lee , P. C. Myers , J. P. Williams

Low-mass stars like our Sun begin their evolution within cold (10 K) and dense ($\sim 10^5$ cm$^{-3}$) cores of gas and dust. The physical structure of starless cores is best probed by thermal emission of dust grains. We present a high…

Astrophysics of Galaxies · Physics 2023-04-05 Samantha Scibelli , Yancy Shirley , Anika Schmiedeke , Brian Svoboda , Ayushi Singh , James Lilly , Paola Caselli

We present a unified model for molecular core formation and evolution, based on numerical simulations of converging, supersonic flows. Our model applies to star formation in GMCs dominated by large-scale turbulence, and contains four main…

Solar and Stellar Astrophysics · Physics 2009-06-25 Hao Gong , Eve C. Ostriker

Motivated by the observation of extended stellar cores in dark matter (DM) dominated dwarf galaxies, this study investigates a simple mechanism by which stellar cores can form as a result of DM halo expansion. Several non-CDM models predict…

Astrophysics of Galaxies · Physics 2025-10-22 Jorge Sanchez Almeida , Angel R. Plastino , Ignacio Trujillo

Chemical reactions in starless molecular clouds are heavily dependent on interactions between gas phase material and solid phase dust and ices. We have observed the abundance and distribution of molecular gases in the cold, starless core DC…

Astrophysics of Galaxies · Physics 2013-01-15 E. E. Hardegree-Ullman , J. Harju , M. Juvela , O. Sipila , D. C. B. Whittet , S. Hotzel

The formation scenario of brown dwarfs is still unclear because observational studies to investigate its initial condition are quite limited. Our systematic survey of nearby low-mass star-forming regions using the Atacama Compact Array (aka…

We present the results of a mid-infrared (7 micron) imaging survey of a sample of 24 starless dense cores carried out at an angular resolution of 6 arcsec with the ISOCAM camera aboard the Infrared Space Observatory (ISO). The targeted…

We present a solution for the observed core fragmentation of filaments in the Taurus L1517 dark cloud which previously could not be explained (Hacar et. al 2011). Core fragmentation is a vital step for the formation of stars. Observations…

Solar and Stellar Astrophysics · Physics 2017-05-16 Stefan Heigl , Andreas Burkert , Alvaro Hacar

Abridged: We use three-dimensional SPH simulations to investigate the collapse of low-mass prestellar cores and the formation and early evolution of protostellar discs. The initial conditions are slightly supercritical Bonnor-Ebert spheres…

Astrophysics of Galaxies · Physics 2015-05-13 S. Walch , A. Burkert , A. Whitworth , T. Naab , M. Gritschneder

Stars like our Sun form in self-gravitating dense and cold structures within interstellar clouds, called pre-stellar cores. Although much is known about the physical structure of dense clouds just before and soon after the switch-on of a…

The infrared dark clouds (IRDCs) G11.11$-$0.12 and G28.34$+$0.06 are two of the best-studied IRDCs in our Galaxy. These two clouds host clumps at different stages of evolution, including a massive dense clump in both clouds that is dark…

The current generation of millimeter interferometers have revealed a population of compact (r <~ 0.1 pc), massive (M ~ 100 Msun) gas cores that are the likely progenitors of massive stars. I review models for the evolution of these objects…

Astrophysics · Physics 2007-05-23 Mark R. Krumholz

Rotating proto-neutron stars can be important sources of gravitational waves to be searched for by present-day and future interferometric detectors. It was demonstrated by Imshennik that in extreme cases the rapid rotation of a collapsing…

High Energy Astrophysical Phenomena · Physics 2016-08-18 K. A. Postnov , A. G. Kuranov , D. A. Kolesnikov , S. B. Popov , N. K. Porayko

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