The Interplay of Gas, Dust, and Magnetorotational Instability in Magnetized Protoplanetary Disks
Author: Timmy N. Delage
Publisher:
Published: 2023
Total Pages: 0
ISBN-13:
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Author: Timmy N. Delage
Publisher:
Published: 2023
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAuthor: Michael V. Lesniak III
Publisher:
Published: 2012
Total Pages: 177
ISBN-13:
DOWNLOAD EBOOKUnderstanding the temperature structure of protoplanetary disks (PPDs) is paramount to modeling disk evolution and future planet formation. PPDs around T Tauri stars have two primary heating sources, protostellar irradiation, which depends on the flaring of the disk, and accretional heating as viscous coupling between annuli dissipate energy. I have written a "1.5-D" radiative transfer code to calculate disk temperatures assuming hydrostatic and radiative equilibrium. The model solves for the temperature at all locations simultaneously using Rybicki's method, converges rapidly at high optical depth, and retains full frequency dependence. The likely cause of accretional heating in PPDs is the magnetorotational instability (MRI), which acts where gas ionization is sufficiently high for gas to couple to the magnetic field. This will occur in surface layers of the disk, leaving the interior portions of the disk inactive ("dead zone"). I calculate temperatures in PPDs undergoing such "layered accretion." Since the accretional heating is concentrated far from the midplane, temperatures in the disk's interior are lower than in PPDs modeled with vertically uniform accretion. The method is used to study for the first time disks evolving via the magnetorotational instability, which operates primarily in surface layers. I find that temperatures in layered accretion disks do not significantly differ from those of "passive disks," where no accretional heating exists. Emergent spectra are insensitive to active layer thickness, making it difficult to observationally identify disks undergoing layered vs. uniform accretion. I also calculate the ionization chemistry in PPDs, using an ionization network including multiple charge states of dust grains. Combined with a criterion for the onset of the MRI, I calculate where the MRI can be initiated and the extent of dead zones in PPDs. After accounting for feedback between temperature and active layer thickness, I find the surface density of the actively accreting layers falls rapidly with distance from the protostar, leading to a net outward flow of mass from ~0.1 to 3 AU. The clearing out of the innermost zones is possibly consistent with the observed behavior of recently discovered "transition disks."
Author: Bo Reipurth
Publisher: University of Arizona Press
Published: 2007
Total Pages: 994
ISBN-13: 9780816526543
DOWNLOAD EBOOK'Protostars and Planets V' builds on the latest results from recent advances in ground and space-based astronomy and in numerical computing techniques to offer the most detailed and up-to-date picture of star and planet formation - including the formation and early evolution of our own solar system.
Author: International Astronomical Union. Symposium
Publisher: Cambridge University Press
Published: 2009-06-11
Total Pages: 716
ISBN-13: 9780521889902
DOWNLOAD EBOOKIAU Symposium 259 presents the first interdisciplinary, comprehensive review of the role of cosmic magnetic fields, involving astronomers and physicists from across the community. Offering both theoretical and observational topics ranging from Earth's habitability to the origin of the universe, this is an invaluable summary for researchers and graduate students.
Author: Katherine A. Kretke
Publisher:
Published: 2010
Total Pages: 344
ISBN-13:
DOWNLOAD EBOOKAuthor: Patrick Michel
Publisher: University of Arizona Press
Published: 2015-12-31
Total Pages: 946
ISBN-13: 0816532133
DOWNLOAD EBOOK"More than forty chapters detail our current astronomical, compositional, geological, and geophysical knowledge of asteroids, as well as their unique physical processes and interrelationships with comets and meteorites"--Provided by publisher.
Author: Martin Pessah
Publisher: Springer
Published: 2017-12-04
Total Pages: 383
ISBN-13: 3319606093
DOWNLOAD EBOOKThis book's interdisciplinary scope aims at bridging various communities: 1) cosmochemists, who study meteoritic samples from our own solar system, 2) (sub-) millimetre astronomers, who measure the distribution of dust and gas of star-forming regions and planet-forming discs, 3) disc modellers, who describe the complex photo-chemical structure of parametric discs to fit these to observation, 4) computational astrophysicists, who attempt to decipher the dynamical structure of magnetised gaseous discs, and the effects the resulting internal structure has on the aerodynamic re-distribution of embedded solids, 5) theoreticians in planet formation theory, who aim to piece it all together eventually arriving at a coherent holistic picture of the architectures of planetary systems discovered by 6) the exoplanet observers, who provide us with unprecedented samples of exoplanet worlds. Combining these diverse fields the book sheds light onto the riddles that research on planet formation is currently confronted with, and paves the way for a comprehensive understanding of the formation, evolution, and dynamics of young solar systems. The chapters ‘Chondrules – Ubiquitous Chondritic Solids Tracking the Evolution of the Solar Protoplanetary Disk’, ‘Dust Coagulation with Porosity Evolution’ and ‘The Emerging Paradigm of Pebble Accretion’ are published open access under a CC BY 4.0 license via link.springer.com.
Author: Alexander Lazarian
Publisher: Springer
Published: 2014-11-14
Total Pages: 627
ISBN-13: 3662446251
DOWNLOAD EBOOKThis volume presents the current knowledge of magnetic fields in diffuse astrophysical media. Starting with an overview of 21st century instrumentation to observe astrophysical magnetic fields, the chapters cover observational techniques, origin of magnetic fields, magnetic turbulence, basic processes in magnetized fluids, the role of magnetic fields for cosmic rays, in the interstellar medium and for star formation. Written by a group of leading experts the book represents an excellent overview of the field. Nonspecialists will find sufficient background to enter the field and be able to appreciate the state of the art.
Author: Jeffrey Fung
Publisher:
Published: 2015
Total Pages:
ISBN-13:
DOWNLOAD EBOOKAuthor: Michael Perryman
Publisher: Cambridge University Press
Published: 2018-08-30
Total Pages: 973
ISBN-13: 1108419771
DOWNLOAD EBOOKA complete and in-depth review of exoplanet research, covering the discovery methods, physics and theoretical background.