Results 51 to 60 of about 801 (259)

Variabiity of young stellar objects: Accretion, disks, outflows, and magnetic activity [PDF]

Astronomische Nachrichten, 2015
AbstractVariability is a key characteristic of young stars. Two major origins may be distinguished: a scaled‐up version of the magnetic activity seen on main‐sequence stars and various processes related to circumstellar disks, accretion, and outflows. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
openaire   +2 more sources

ON THE ROLE OF DISKS IN THE FORMATION OF STELLAR SYSTEMS: A NUMERICAL PARAMETER STUDY OF RAPID ACCRETION [PDF]

The Astrophysical Journal, 2009
We study rapidly accreting, gravitationally unstable disks with a series of global, three dimensional, numerical experiments using the code ORION. In this paper we conduct a numerical parameter study focused on protostellar disks, and show that one can predict disk behavior and the multiplicity of the accreting star system as a function of two ...
Kratter, Kaitlin M, Matzner, Christopher D., Krumholz, Mark, Klein, Richard I.   +3 more
openaire   +3 more sources

Creep Properties and Deformation Mechanism of Additively Manufactured NiAl‐CrMo Composites

Advanced Engineering Materials, EarlyView.
Additively manufactured NiAl‐CrMo composites contain numerous interfaces and cell boundaries that control their creep response. At 700°C under high applied stress, creep is dominated by dislocation‐controlled power‐law mechanisms. At 800°C–900°C and lower stresses, creep is primarily diffusion‐controlled along cell boundaries.
Jan Vollhüter, Andreas Bezold, Johan Westraadt, Katharina Fiegl, Subham Chattoraj, Benjamin Wahlmann, Carolin Körner, Michael Mills, Mathias Göken, Steffen Neumeier   +9 more
wiley   +1 more source

Properties of Galaxies with Counter-rotating Stellar Disks in the MaNGA Survey

The Astrophysical Journal
The gas accretion process can fuel both star formation and black hole activity, playing a critical role in galaxy evolution. The counter-rotating structures are believed to originate from gas accretion, serving as an ideal laboratory to study its impact ...
Min Bao, Zhenyu Tang, Yanmei Chen, Yong Shi, Qiusheng Gu   +4 more
doaj   +1 more source

Wind accretion by a binary stellar system and disc formation [PDF]

Monthly Notices of the Royal Astronomical Society, 2004
I calculate the specific angular momentum of mass accreted by a binary system embedded in the dense wind of a mass losing asymptotic giant branch star. The accretion flow is of the Bondi-Hoyle-Lyttleton type. For most of the relevant parameters space the flow is basically an isothermal high Mach number accretion flow. I find that when the orbital plane
openaire   +2 more sources

Recycling of NiTi Shape Memory Alloys: Fundamental and Technological Aspects of a Vacuum Induction Melting Processing Route

Advanced Engineering Materials, EarlyView.
The present study investigates recycling of NiTi shape memory alloys via vacuum induction melting. An ingot was synthesized from elemental Ni and Ti and subjected to three subsequent remelting cycles. Remelting increases process durations and impurity levels and adversely affects microstructures and functional properties.
Sakia Sophia Noorzayee, Son Tung Mai, Sarath Menon, Braulio Gadiel Sánchez Ortega, Ralf Drautz, Alexander Kauffmann, Gunther Eggeler, Jan Frenzel   +7 more
wiley   +1 more source

Impact of the Accretion Disk Thickness on the Polarization of the Thermal Emission from Stellar Mass Black Holes

The Astrophysical Journal, 2023
The Imaging X-ray Polarimetry Explorer, launched in 2021 December, enables precision measurements of the energy-dependent polarization of the X-ray emission from stellar mass and supermassive black holes.
Andrew Thomas West, Henric Krawczynski
doaj   +1 more source

Experimental Characterization and Constitutive Modeling of the Effect of Prior Inelastic Strain on the Viscoplastic Behavior of AD730 at 700 °C

Advanced Engineering Materials, EarlyView.
This study shows that superalloys used in aircraft engine disks become much more prone to deformation at high temperatures if they have been strained during manufacturing. This effect increases with the level of prior strain but eventually reaches a limit.
Fabio Machado Alves da Fonseca, Patrick Villechaise, Malik Durand, Arnaud Longuet, Florent Coudon, Loïc Signor, Julien De Jaeger, Dominique Eyidi, Nathalie Bozzolo, Jonathan Cormier   +9 more
wiley   +1 more source

The Population of Massive Stars in Active Galactic Nuclei Disks

The Astrophysical Journal
Gravitational instability in the outskirts of active galactic nuclei (AGN) disks leads to disk fragmentation and formation of ∼300 M _⊙ supermassive stars with potentially long lifetimes.
Yi-Xian Chen, Douglas N. C. Lin
doaj   +1 more source

Mass Accretion Processes in Young Stellar Objects: Role of Intense Flaring Activity

Acta Polytechnica CTU Proceedings, 2014
According to the magnetospheric accretion scenario, young low-mass stars are surrounded by circumstellar disks which they interact with through accretion of mass. The accretion builds up the star to its nal mass and is also believed to power the mass out
Salvatore Orlando, Fabio Reale, Giovanni Peres, Andrea Mignone   +3 more
doaj   +1 more source