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Related papers: Accretion Disks around Young Objects. I. The Detai…

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The thermal instability of accretion disks is widely used to explain the activity of cataclysmic variables, but its development in protoplanetary disks has been studied in less detail. We present a semi-analytical stationary model for…

Earth and Planetary Astrophysics · Physics 2023-07-31 Ya. N. Pavlyuchenkov , V. V. Akimkin , A. P. Topchieva , E. I. Vorobyov

We examine heating and cooling in protostellar disks using 3-D radiation-MHD calculations of a patch of the Solar nebula at 1 AU, employing the shearing-box and flux-limited radiation diffusion approximations. The disk atmosphere is ionized…

Earth and Planetary Astrophysics · Physics 2015-05-27 S. Hirose , N. J. Turner

We perform numerical analyses of the structure induced by gravitational instabilities in cooling gaseous accretion discs. For low enough cooling rates a quasi-steady configuration is reached, with the instability saturating at a finite…

Astrophysics · Physics 2009-11-13 Peter Cossins , Giuseppe Lodato , Cathie Clarke

Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disk. One of the most important new invention of this theory was the…

Astrophysics · Physics 2009-11-07 G. S. Bisnovatyi-Kogan , R. V. E. Lovelace

Radiation emitted from an accretion disk around a massive black hole is a widely discussed model for the UV/soft X-ray excess emission observed in the spectra of many AGN. A self-consistent calculation of the structure and the emerging…

Astrophysics · Physics 2012-07-02 T. Doerrer , H. Riffert , R. Staubert , H. Ruder

The global structure of optically thin hot accretion disks with radial advection included has been investigated. We solve the full energy conservation equation explicitly and construct the radial structure of the disk. It is found that…

Astrophysics · Physics 2016-08-30 Xingming Chen

We investigate the thermal stability of the outer layers of accretion discs in which the local viscous energy dissipation rate scales with the pressure as for standard Shakura-Sunyaev discs. By solving for the accretion disc vertical…

Astrophysics · Physics 2009-10-31 Martijn de Kool , Dayal T. Wickramasinghe

Protoplanetary disks are often assumed to change slowly and smoothly during planet formation. Here, we investigate the time evolution of isolated disks subject to viscosity and a disk wind. The viscosity is assumed to increase rapidly at…

Earth and Planetary Astrophysics · Physics 2024-03-27 John Chambers

Protoplanetary disks are mainly heated by radiation from the central star. Since the incident stellar flux at any radius is sensitive to the disk structure near that location, an unstable feedback may be present. Previous investigations…

Astrophysics · Physics 2009-11-13 Sei-ichiro Watanabe , D. N. C. Lin

We determine inner disk sizes and temperatures for four solar-type (1-2 M$_{\odot}$) classical T Tauri stars (AS 207A, V2508 Oph, AS 205A, and PX Vul) using 2.2 $\mu$m observations from the Keck Interferometer. Nearly contemporaneous…

Astrophysics · Physics 2009-11-10 J. A. Eisner , L. A. Hillenbrand , R. J. White , R. L. Akeson , A. I. Sargent

We present a two-layer accretion disc model developed to simultaneously fit optical long baseline visibilities and spectral energy distributions of T Tauri accretion discs. Our model includes viscous heating and absorption of stellar…

Astrophysics · Physics 2009-11-07 Regis Lachaume , Fabien Malbet , Jean-Louis Monin

We explore the properties of cold gravitoturbulent accretion disks - non-fragmenting disks hovering on the verge of gravitational instability - using a realistic prescription for the effective viscosity caused by gravitational torques. This…

Earth and Planetary Astrophysics · Physics 2009-10-02 Roman R. Rafikov

Although stars accrete mass throughout the first few Myr of their lives, the physical mechanism that drives disk accretion in the T Tauri phase is uncertain, and diagnostics that probe the nature of disk accretion have been elusive,…

Solar and Stellar Astrophysics · Physics 2017-09-20 Joan R. Najita , Mate Adamkovics

Recent work by Pringle and by Maloney, Begelman & Pringle has shown that geometrically thin, optically thick, accretion disks are unstable to warping driven by radiation torque from the central source. In this paper we generalize the study…

Astrophysics · Physics 2009-10-30 Philip R. Maloney , Mitchell C. Begelman , Michael A. Nowak

We describe a model for the long term evolution of a circumplanetary disk that is fed mass from a circumstellar disk and contains regions of low turbulence (dead zones). We show that such disks can be subject to accretion driven outbursts,…

Earth and Planetary Astrophysics · Physics 2015-06-04 S. H. Lubow , R. G. Martin

We discuss the importance of accretion in calculating disk models for young stellar objects. In particular, we show that a disk inner rim, irradiated by both the star and the accretion shocks at the stellar surface, can naturally explain…

Astrophysics · Physics 2007-05-23 Paola D'Alessio , Nuria Calvet , Lee Hartmann , James Muzerolle , Michael Sitko

The accretion disk around a rotating magnetic star (neutron star, white dwarf or T Tauri star) is subjected to periodic vertical magnetic forces from the star, with the forcing frequency equal to the stellar spin frequency or twice the spin…

Astrophysics · Physics 2009-11-13 Dong Lai , Hang Zhang

By taking into account the local energy balance per unit volume between the viscous heating and the advective cooling plus the radiative cooling, we investigate the vertical structure of radiation pressure-supported accretion disks in…

High Energy Astrophysical Phenomena · Physics 2012-07-31 Wei-Min Gu

The local stability of accretion disks with advection is studied together with the considerations of radial viscous force and thermal diffusion. For a geometrically thin, radiative cooling dominated disk, the thermal diffusion has nearly no…

Astrophysics · Physics 2009-10-28 Xue-Bing Wu , Qi-Bin Li

The temperature in most parts of a protoplanetary disk is determined by irradiation from the central star. Numerical experiments of Watanabe \& Lin (2008) suggested that such disks, also called `passive disks', suffer from a thermal…

Earth and Planetary Astrophysics · Physics 2021-12-22 Yanqin Wu , Yoram Lithwick