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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…

Low-mass protostars form from condensations inside molecular clouds when gravity overwhelms thermal and magnetic supporting forces. The first phases of the formation of a solar-type star are characterized by dramatic changes not only in the…

Astrophysics · Physics 2007-05-23 C. Ceccarelli , P. Caselli , E. Herbst , X. Tielens , E. Caux

(Abridged) We present evidence that low-mass starless cores, the simplest units of star formation, are systematically differentiated in their chemical composition. Molecules including CO and CS almost vanish near the core centers, where the…

Astrophysics · Physics 2008-11-26 M. Tafalla , P. C. Myers , P. Caselli , C. M. Walmsley , C. Comito

We investigate molecular evolution in a star-forming core that is initially a hydrostatic starless core and collapses to form a low-mass protostar. The results of a one-dimensional radiation-hydrodynamics calculation are adopted as a…

Astrophysics · Physics 2009-11-13 Yuri Aikawa , Valentine Wakelam , Robin T. Garrod , Eric Herbst

\abridged The nuclei of active galaxies harbor massive young stars, an accreting central black hole, or both. In order to determine the physical conditions that pertain to molecular gas close to the sources of radiation, numerical models…

Astrophysics · Physics 2009-11-11 R. Meijerink , M. Spaans , F. P. Israel

Several studies have shown that the column densities inferred from broad absorption lines (BALs) require extremely high metallicities and phosphorus overabundances -- apparently in conflict with other abundance diagnostics. Here I use HST…

Astrophysics · Physics 2007-05-23 F. Hamann

Pressure-induced superconductivity and structural phase transitions in phosphorous (P) are studied by resistivity measurements under pressures up to 170 GPa and fully $ab-initio$ crystal structure and superconductivity calculations up to…

Despite its major role in the evolution of the interstellar medium, the formation of high-mass stars (M > 10 Msol) is still poorly understood. Two types of massive star cluster precursors, the so-called Massive Dense Cores (MDCs), have been…

Astrophysics of Galaxies · Physics 2015-05-19 M. G. Marseille , F. F. S. van der Tak , F. Herpin , T. Jacq

Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC+10216 and CRL2688 from observations of an emission line at 266.9 GHz attributable to the J=1-0 rotational transition. We report the detection of the…

Astrophysics of Galaxies · Physics 2015-06-22 M. Agundez , J. Cernicharo , L. Decin , P. Encrenaz , D. Teyssier

We present phosphorus abundance measurements for a total of 102 giant stars, including 82 stars in 24 open clusters and 20 Cepheids, based on high-resolution near-infrared spectra obtained with GIANO-B. Evolution of phosphorus abundance,…

We recently proposed that molecular cloud dense cores undergo a prolonged period of quasi-static contraction prior to true collapse. This theory could explain the observation that many starless cores exhibit, through their spectral line…

Solar and Stellar Astrophysics · Physics 2015-05-19 Steven W. Stahler , Jeffrey J. Yen

The measurement of the mass 1.97 +/- 0.04 M_sun for PSR J1614-2230 provides a new constraint on the equation of state and composition of matter at high densities. In this contribution we investigate the possibility that the dense cores of…

Nuclear Theory · Physics 2012-09-20 R. Lastowiecki , D. Blaschke , H. Grigorian , S. Typel

We have made an extensive 1.2mm continuum mosaicing study of the Cygnus X molecular cloud complex using the MAMBO cameras at the IRAM 30 m telescope. We then compared our mm maps with mid-IR images, and have made SiO(2-1) follow-up…

Astrophysics · Physics 2008-01-10 Frédérique Motte , S. Bontemps , P. Schilke , N. Schneider , K. M. Menten , D. Broguière

Pre-stellar cores within molecular clouds provide the very initial conditions in which stars are formed. We use the IRAM 30m telescope and the PdBI to study the chemical and physical properties of the starless core FeSt 1-457 (Core 109), in…

Context. he study of prestellar cores is essential to understanding the initial stages of star formation. With $Herschel$ more cold clumps have been detected than ever before. For this study we have selected 21 cold clumps from 20…

Astrophysics of Galaxies · Physics 2015-05-06 A. Parikka , M. Juvela , V. -M. Pelkonen , J. Malinen , J. Harju

Neutron stars contain matter in one of the densest forms found in the Universe. This feature, together with the unprecedented progress in observational astrophysics, makes such stars superb astrophysical laboratories for a broad range of…

Astrophysics · Physics 2007-05-23 F. Weber , R. Negreiros , P. Rosenfield

The Trifid nebula is a young HII region undergoing a burst of star formation. In this article, we report on far-infrared and millimeter continuum and line observations of several massive and bright protostellar sources in the vicinity of…

Astrophysics · Physics 2009-10-31 B. Lefloch , J. Cernicharo

The initial stage of star formation is a complex area study because of its high density and low temperature. Under such conditions, many molecules become depleted from the gas phase by freezing out onto dust grains. However, the deuterated…

The potential detection of ppb levels phosphine (PH3) in the clouds of Venus through millimeter-wavelength astronomical observations is extremely surprising as PH3 is an unexpected component of an oxidized environment of Venus. A thorough…

We performed detailed spectroscopic analyses of a young C-rich planetary nebula (PN) Jonckheere900 (J900) in order to characterise the properties of the central star and nebula. Of the derived 17 elemental abundances, we present the first…

Solar and Stellar Astrophysics · Physics 2020-01-08 Masaaki Otsuka , Siek Hyung
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