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Related papers: Be Star Disk Models in Consistent Vertical Hydrost…

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Gas accretion, hot ($\sim 10^6\,{\rm K}$) atmospheres, and a tilt between the rotation axes of the disc and the atmosphere are all common predictions of standard galaxy evolution theory for massive star-forming galaxies at low redshift.…

One-armed oscillation modes in the circumstellar discs of Be stars may explain the cyclical variations in their emission lines. We show that a three-dimensional effect, involving vertical motion and neglected in previous treatments,…

Astrophysics · Physics 2016-08-17 Gordon I. Ogilvie

Circumplanetary disks can be found around forming giant planets, regardless of whether core accretion or gravitational instability built the planet. We carried out state-of-the-art hydrodynamical simulations of the circumplanetary disks for…

Earth and Planetary Astrophysics · Physics 2016-12-07 J. Szulágyi , L. Mayer , T. Quinn

Molecular gas disks are generally Toomre stable ($Q_T>$1) and yet clearly gravitationally unstable to structure formation as evidenced by the existence of molecular clouds and ongoing star formation. This paper adopts a 3D perspective to…

Astrophysics of Galaxies · Physics 2022-10-12 Sharon E. Meidt

Aims: We explore the long-term evolution of young protoplanetary disks with different approaches to computing the thermal structure determined by various cooling and heating processes in the disk and its surroundings. Methods: Numerical…

Earth and Planetary Astrophysics · Physics 2020-07-01 Eduard I. Vorobyov , Ryoki Matsukoba , Kazuyuki Omukai , Manuel Guedel

We explore various instability models for the onset of star formation in irregular galaxies. Critical gas densities are calculated for gravitational instabilities with a thin, pure-gas disk, and with a thick disk composed of gas and a…

Astrophysics · Physics 2009-10-30 Deidre A. Hunter , Bruce G. Elmegreen , Aomawa L. Baker

We use a smoothed particle hydrodynamics (SPH) code to examine the effects of misaligned binary companions on Be star discs. We systematically vary the degree of misalignment between the disc and the binary orbit, as well as the disc…

Solar and Stellar Astrophysics · Physics 2017-08-09 Isabelle H. Cyr , Carol E. Jones , Despina Panoglou , Alex C. Carciofi , Atsuo T. Okazaki

We investigated a hydrostatic equilibrium model of the Milky Way following Parker (1966), to constrain the large scale properties of the interstellar medium. In our approach we found an excellent agreement between our simple hydrostatic…

Astrophysics · Physics 2007-05-23 P. M. W. Kalberla , J. Kerp

In this paper a simple analytical model for the steady-state evolution of debris disks due to collisions is confronted with Spitzer observations of main sequence A stars. All stars are assumed to have planetesimal belts with a distribution…

Astrophysics · Physics 2011-02-11 M. C. Wyatt , R. Smith , K. Y. L. Su , G. H. Rieke , J. S. Greaves , C. A. Beichman , G. Bryden

We analyze the V-band photometry data of the Be star omega CMa, observed during the last four decades. The data is fitted by hydrodynamic models based on the viscous decretion disk (VDD) theory, in which a disk around a fast-spinning Be…

Solar and Stellar Astrophysics · Physics 2017-02-24 Mohammad Reza Ghoreyshi , Alex Cavalieri Carciofi

A study on the photosphere and disc of the Be star $\beta$ Psc is presented. We recover almost 40 years of high-resolution spectroscopic observations and additional data gathered from the BeSS database. We evaluate the photospheric…

Solar and Stellar Astrophysics · Physics 2020-09-17 Ronaldo S. Levenhagen , Marcos P. Diaz , Eduardo B. Amôres , Nelson V. Leister

In the last decade, the viscous decretion disk model has emerged as the new paradigm for Be star disks. In this contribution, we propose a simple analytical model to estimate the continuum infrared excess arising from these circumstellar…

Solar and Stellar Astrophysics · Physics 2016-04-14 Rodrigo G. Vieira , Alex C. Carciofi , Jon E. Bjorkman

We investigate how the formation and structure of circumplanetary disks (CPDs) varies with planet mass and protoplanetary disk aspect ratio. Using static mesh refinement and a near-isothermal equation of state, we perform a small parameter…

Earth and Planetary Astrophysics · Physics 2025-05-15 Sabina Sagynbayeva , Rixin Li , Aleksandra Kuznetsova , Zhaohuan Zhu , Yan-Fei Jiang , Philip J. Armitage

Estimates of the dynamical surface mass density at the solar Galactocentric distance are commonly derived assuming that the disk is in vertical equilibrium with the Galactic potential. This assumption has recently been called into question,…

Astrophysics of Galaxies · Physics 2015-05-27 F. J. Sanchez-Salcedo , Chris Flynn , A. M. Hidalgo-Gamez

Protostellar disks around young protostars exhibit diverse properties, with their radii ranging from less than ten to several hundred au. To investigate the mechanisms shaping this disk radius distribution, we compiled a sample of 27 Class…

Solar and Stellar Astrophysics · Physics 2024-08-23 Hsi-Wei Yen , Yueh-Ning Lee

This paper describes a practical model for the polarization of Be stars which can be used to estimate roughly the physical parameters for optically thin circumstellar envelopes from broadband UBVRI photopolarimetry data. Analysis of…

Astrophysics · Physics 2009-11-06 David McDavid

Aims: To calculate chemistry and gas temperature of evolving protoplanetary disks with decreasing mass or dust settling, and to explore the sensitivity of gas-phase tracers. Methods: The density and dust temperature profiles for a range of…

Astrophysics · Physics 2009-11-11 B. Jonkheid , C. P. Dullemond , M. R. Hogerheijde , E. F. van Dishoeck

We use a high-resolution grid-based hydrodynamics method to simulate the multi-phase interstellar medium in a Milky Way-size quiescent disk galaxy. The models are global and three-dimensional, and include a treatment of star formation and…

Astrophysics · Physics 2009-11-13 Elizabeth J. Tasker , Greg L. Bryan

We formulate a parametrized model of embedded protostellar disks and test its ability to estimate disk properties by fitting dust-continuum observations. The main physical assumptions of our model are motivated by a recent theoretical study…

Solar and Stellar Astrophysics · Physics 2024-02-15 Wenrui Xu

We investigate the nonlinear growth stages of bending instability in stellar disks with exponential radial density profiles.We found that the unstable modes are global (the wavelengths are larger than the disk scale lengths) and that the…

Astrophysics · Physics 2009-11-07 N. Ya. Sotnikova , S. A. Rodionov
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