scholarly journals Protoplanetary Disk Evolution and Influence of the Host Star

2013 ◽  
Vol 8 (S299) ◽  
pp. 374-375
Author(s):  
Kévin Baillié ◽  
Sébastien Charnoz
Keyword(s):  
Numerical Model ◽  
Surface Density ◽  
Accretion Rate ◽  
Protoplanetary Disk ◽  
Star Mass ◽  
Mass Accretion Rate ◽  
Disk Mass ◽  
Rate Versus ◽  
Self Consistent ◽  
Disk Evolution

AbstractBased on a self-consistent coupling between protoplanetary disk thermodynamics, photosphere geometry and dynamics we designed a 1D-hydrodynamical numerical model for the spreading of the disks as a function of the star characteristics. We found that the evolution timescale increases for more massive or for a steeper surface density disk, and decreases for bigger stars or less turbulent disks. We found a strong dependency of the mass accretion rate versus the disk mass and a weaker dependency versus the star mass. Coupled with observed similar conclusions, we derived that the disk mass is scaling as M*1.6.

scholarly journals X-shooter survey of disk accretion in Upper Scorpius

2020 ◽  
Vol 639 ◽  
pp. A58 ◽  
Author(s):  
C. F. Manara ◽  
A. Natta ◽  
G. P. Rosotti ◽  
J. M. Alcalá ◽  
B. Nisini ◽  
...  
Keyword(s):  
Accretion Rate ◽  
Protoplanetary Disks ◽  
Young Stellar Objects ◽  
High Mass ◽  
Star Forming ◽  
Mass Accretion Rate ◽  
Disk Mass ◽  
Accretion Rates ◽  
Disk Evolution ◽  
Simple Models

Determining the mechanisms that drive the evolution of protoplanetary disks is a necessary step toward understanding how planets form. For this work, we measured the mass accretion rate for young stellar objects with disks at age > 5 Myr, a critical test for the current models of disk evolution. We present the analysis of the spectra of 36 targets in the ∼5–10 Myr old Upper Scorpius star-forming region for which disk masses were measured with ALMA. We find that the mass accretion rates in this sample of old but still surviving disks are similarly high as those of the younger (∼1−3 Myr old) star-forming regions of Lupus and Chamaeleon I, when considering the dependence on stellar and disk mass. In particular, several disks show high mass accretion rates ≳10−9 M⊙ yr−1 while having low disk masses. Furthermore, the median values of the measured mass accretion rates in the disk mass ranges where our sample is complete at a level ∼60−80% are compatible in these three regions. At the same time, the spread of mass accretion rates at any given disk mass is still > 0.9 dex, even at age > 5 Myr. These results are in contrast with simple models of viscous evolution, which would predict that the values of the mass accretion rate diminish with time, and a tighter correlation with disk mass at age > 5 Myr. Similarly, simple models of internal photoevaporation cannot reproduce the observed mass accretion rates, while external photoevaporation might explain the low disk masses and high accretion rates. A possible partial solution to the discrepancy with the viscous models is that the gas-to-dust ratio of the disks at ∼5–10 Myr is significantly different and higher than the canonical 100, as suggested by some dust and gas disk evolution models. The results shown here require the presence of several interplaying processes, such as detailed dust evolution, external photoevaporation, and possibly MHD winds, to explain the secular evolution of protoplanetary disks.

scholarly journals Global Protoplanetary Disk Simulations: Dead Zone Formation and FUor Outbursts

2018 ◽  
Vol 14 (S345) ◽  
pp. 324-325
Author(s):  
Kundan Kadam ◽  
E. Vorobyov ◽  
Zs. Regály ◽  
Á. Kóspál ◽  
P. Ábráham
Keyword(s):  
Molecular Cloud ◽  
Dead Zone ◽  
Protoplanetary Disk ◽  
Model Parameters ◽  
Zone Formation ◽  
Hydrodynamic Simulations ◽  
Disk Structure ◽  
Self Consistent ◽  
Disk Evolution ◽  
Collapse Phase

AbstractWe conducted global hydrodynamic simulations of protoplanetary disk evolution with an adaptive Shakura-Sunyaev α prescription to represent the layered disk structure, and starting with the collapse phase of the molecular cloud. With the canonical values of model parameters, self-consistent dead zones formed at the scale of a few au. The instabilities associated with the dead zone and corresponding outbursts, similar to FUor eruptions, were also observed in the simulations.

scholarly journals The relativistic mass accretion rate for accretion disk in the equatorial of rapidly rotating neutron stars

2021 ◽  
Vol 1869 (1) ◽  
pp. 012156
Author(s):  
A Yasrina ◽  
N Widianingrum ◽  
N S Risdianto ◽  
D Andra ◽  
N A Pramono ◽  
...  
Keyword(s):  
Neutron Stars ◽  
Accretion Disk ◽  
Accretion Rate ◽  
Mass Accretion Rate ◽  
Relativistic Mass

scholarly journals Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars

2008 ◽  
Vol 4 (S259) ◽  
pp. 395-396 ◽  
Author(s):  
Swetlana Hubrig ◽  
C. Grady ◽  
M. Schöller ◽  
O. Schütz ◽  
B. Stelzer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Survey ◽  
Accretion Rate ◽  
Be Stars ◽  
General Correlation ◽  
X Ray ◽  
Mass Accretion Rate ◽  
Debris Disk ◽  
Magnetic Nature

AbstractWe present the results of a new magnetic field survey of Herbig Ae/Be and A debris disk stars. They are used to determine whether magnetic field properties in these stars are correlated with the mass-accretion rate, disk inclinations, companion(s), Silicates, PAHs, or show a more general correlation with age and X-ray emission as expected for the decay of a remnant dynamo.

scholarly journals Rapid Mass Accretion in the Symbiotic Star AG Dra

1987 ◽  
Vol 93 ◽  
pp. 759-762
Author(s):  
T. Iijima
Keyword(s):  
White Dwarf ◽  
Accretion Rate ◽  
Symbiotic Star ◽  
Mass Accretion Rate ◽  
Accretion Process ◽  
Rapid Mass

AbstractThe mass accretion process onto the hot component of AG Dra and its explosive phenomena are discussed. The hot component seems to be a massive white dwarf (M > 1 M⊙). The mass accretion rate is estimated to be about 10−7M⊙/year. Many properties of the explosive phenomena agree with those of mild hydrogen flashes expected from this rapid mass accretion.

scholarly journals H2O maser emission from the Seyfert 2 galaxy IC 2560: evidence for a super-massive black hole and a probe for mass-accretion rate

2002 ◽  
Vol 206 ◽  
pp. 400-403
Author(s):  
Yuko Ishihara ◽  
Naomasa Nakai ◽  
Naoko Iyomoto ◽  
Kazuo Makishima ◽  
Phil Diamond ◽  
...  
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Accretion Rate ◽  
Rotating Disk ◽  
Massive Black Hole ◽  
Central Mass ◽  
Maser Emission ◽  
Mass Accretion Rate ◽  
Systemic Velocity ◽  
Velocity Drift

Our observations of H2O masers have detected some high-velocity features and a secular velocity drift of the systemic features in the Seyfert 2 Galaxy IC 2560. The high-velocity features were blue- and red-shifted from the systemic velocity of 220-420 km s−1 and 210-350 km s−1, respectively. The velocity of the systemic features drifted at a secular rate of 2.62 km s−1 yr−1. Assuming the existence of a compact rotating disk as in NGC 4258, IC 2560 possesses a nuclear disk with inner and outer radii of 0.07 pc and 0.26 pc, respectively, and a confined mass of 2.8 × 106M⊙ at the center, making the central density > 2.1 × 109M⊙ pc−3. Such a dense object cannot be a cluster of stars, and this strongly suggests that the central mass is a super-massive black hole. Since the 2-10 keV luminosity of IC 2560 is 1 × 1041 erg s−1, the mass accretion rate of the suggested black hole must be 2 × 10−5M⊙ yr−1.

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