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Related papers: Efficient ortho-para conversion of H2 on interstel…

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In recent decades, significant attention has been dedicated to analytical and observational studies of the atomic hydrogen (HI) to molecular hydrogen (H2) transition in the interstellar medium. We focussed on the Draco diffuse cloud to gain…

High dust density in the midplane of protoplanetary disks is favorable for efficient grain growth and can allow fast formation of planetesimals and planets, before disks dissipate. Vertical settling and dust trapping in pressure maxima are…

Solar and Stellar Astrophysics · Physics 2022-05-11 M. Villenave , K. R. Stapelfeldt , G. Duchene , F. Menard , M. Lambrechts , A. Sierra , C. Flores , W. R. F. Dent , S. Wolff , A. Ribas , M. Benisty , N. Cuello , C. Pinte

When studying the chemistry of PDRs, time dependence becomes important as visual extinction increases, since certain chemical timescales are comparable to the cloud lifetime. Dust temperature is also a key factor, since it significantly…

Astrophysics of Galaxies · Physics 2019-04-17 Gisela Esplugues , Stephanie Cazaux , Paola Caselli , Seyit Hocuk , Marco Spaans

The efficiency of radial transport of icy solid material from outer disk to the inner disk is currently unconstrained. Efficient radial transport of icy dust grains could significantly alter the composition of the gas in the inner disk. Our…

Earth and Planetary Astrophysics · Physics 2018-04-04 Arthur D. Bosman , Alexander G. G. M. Tielens , Ewine F. van Dishoeck

The polarization of starlight and thermal dust emission, resulting from non-spherical grains aligned with the interstellar magnetic field (B-field), act as a powerful tool to trace the B-field morphologies and strengths in molecular clouds…

Astrophysics of Galaxies · Physics 2026-05-26 Saikhom Pravash

Context: Hydrogen peroxide (HOOH) was recently detected toward \rho Oph A. Subsequent astrochemical modeling that included reactions in the gas phase and on the surface of dust grains was able to explain the observed abundance, and…

Astrophysics of Galaxies · Physics 2012-05-03 B. Parise , P. Bergman , F. Du

Molecular hydrogen is the most abundant molecule in the Universe. It is thought that a large portion of H2 forms by association of hydrogen atoms to polycyclic aromatic hydrocarbons (PAHs). We model the influence of PAHs on total H2…

Astrophysics of Galaxies · Physics 2015-07-01 Leon Boschman , Stéphanie Cazaux , Marco Spaans , Ronnie Hoekstra , Thomas Schlathölter

Grain alignment by radiative torques (RATs) has been extensively studied for various environment conditions, including interstellar medium, dense molecular clouds, and accretion disks, thanks to significant progress in observational,…

Astrophysics of Galaxies · Physics 2015-06-22 Thiem Hoang , A. Lazarian

We present a method to estimate the total gas column density, dust-to-gas and dust-to-metal ratios of distant galaxies from rest-frame optical spectra. The technique exploits the sensitivity of certain optical lines to changes in depletion…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Jarle Brinchmann , Stéphane Charlot , Guinevere Kauffmann , Tim Heckman , Simon D. M. White , Christy Tremonti

We model the effect of grain size distribution in a galaxy on the evolution of CO and H$_2$ abundances. The formation and dissociation of CO and H$_2$ in typical dense clouds are modelled in a manner consistent with the grain size…

Astrophysics of Galaxies · Physics 2023-05-10 Hiroyuki Hirashita

Following from our recent work, we present a detailed analysis of star-formation and interstellar medium (ISM) scaling relations, done on a representative sample of nearby galaxies. H$\alpha$ images are analysed in order to derive the…

Astrophysics of Galaxies · Physics 2024-01-12 Bogdan A. Pastrav

Determining temperatures in molecular clouds from ratios of CO rotational lines or from ratios of continuum emission in different wavelength bands suffers from reduced temperature sensitivity in the high-temperature limit. In theory, the…

Astrophysics · Physics 2008-11-26 W. F. Wall

The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in…

Astrophysics of Galaxies · Physics 2017-08-09 S. Hocuk , L. Szucs , P. Caselli , S. Cazaux , M. Spaans , G. B. Esplugues

Context. Polarized dust emission can be used as a probe for magnetic fields at different scales. In particular, the analysis of the relative orientation between the density structures and the magnetic field projected on the plane of the sky…

Astrophysics of Galaxies · Physics 2021-03-24 Elisabetta R. Micelotta , Mika Juvela , Paolo Padoan , Isabelle Ristorcelli , Dana Alina , Johanna Malinen

The first off-lattice Monte Carlo kinetics model of interstellar dust-grain surface chemistry is presented. The positions of all surface particles are determined explicitly, according to the local potential minima resulting from the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 Robin T. Garrod

Context. The high degree of deuteration observed in some prestellar cores depends on the ortho-to-para H2 ratio through the H3+ fractionation. Aims. We want to constrain the ortho/para H2 ratio across the L183 prestellar core. This is…

There are two major theoretical issues for the star formation law (the relation between the surface densities of molecular gas and star formation rate on a galaxy scale): (i) At low metallicity, it is not obvious that star-forming regions…

Astrophysics of Galaxies · Physics 2018-01-24 Li-Hsin Chen , Hiroyuki Hirashita , Kuan-Chou Hou , Shohei Aoyama , Ikkoh Shimizu , Kentaro Nagamine

A considerable proportion of young stars belong to multiple star systems. Constraining the planet formation processes in multiple stellar systems is then key to understand the global exoplanet population. This study focuses on investigating…

Earth and Planetary Astrophysics · Physics 2025-11-26 Antoine Alaguero , François Ménard , Nicolás Cuello , Álvaro Ribas , Elena Viscardi , Enrique Macías , Miguel Vioque , James Miley

A prominent chemical reaction in interstellar clouds is the formation of molecular hydrogen by recombination, which essentially takes place on dust grain surfaces. Analytical approaches to model such a system have hitherto neglected the…

Astrophysics · Physics 2009-11-11 Ingo Lohmar , Joachim Krug

The ultraviolet and far--ultraviolet spectra of HD 147888 allows to access the v=0 as well as higher vibrational levels of the ground H2 electronic level. We have determined column densities of the H2 molecule on vibrational levels v=0-5…

Astrophysics of Galaxies · Physics 2018-05-02 Piotr Gnacinski
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