Toward Assembling a Comprehensive Database of Substellar Accretion Rates

Abstract Cloud microphysics parameterizations for shallow cumulus clouds are analyzed based on Lagrangian cloud model (LCM) data, focusing on autoconversion and accretion. The autoconversion and accretion rates, A and C, respectively, are calculated directly by capturing the moment of the conversion of individual Lagrangian droplets from cloud droplets to raindrops, and it results in the reproduction of the formulas of A and C for the first time. Comparison with various parameterizations reveals the closest agreement with Tripoli and Cotton, such as and , where and are the mixing ratio and the number concentration of cloud droplets, is the mixing ratio of raindrops, is the threshold volume radius, and H is the Heaviside function. Furthermore, it is found that increases linearly with the dissipation rate and the standard deviation of radius and that decreases rapidly with while disappearing at > 3.5 μm. The LCM also reveals that and increase with time during the period of autoconversion, which helps to suppress the early precipitation by reducing A with smaller and larger in the initial stage. Finally, is found to be affected by the accumulated collisional growth, which determines the drop size distribution.

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The Observational Evidence for Accretion

Symposium - International Astronomical Union ◽

10.1017/s0074180900061805 ◽

1997 ◽

Vol 182 ◽

pp. 391-405 ◽

Cited By ~ 2

Author(s):

Lee Hartmann

Keyword(s):

Large Range ◽

Observational Evidence ◽

Young Stars ◽

Young Stellar Objects ◽

Stellar Objects ◽

T Tauri ◽

Accretion Rates ◽

Low Mass ◽

Stellar Magnetospheres ◽

Mass Ejection

Outflows from low-mass young stellar objects are thought to draw upon the energy released by accretion onto T Tauri stars. I briefly summarize the evidence for this accretion and outline present estimates of mass accretion rates. Young stars show a very large range of accretion rates, and this has important implications for both mass ejection and for the structure of stellar magnetospheres which may truncate T Tauri disks.

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FOCUS-DB: An Online Comprehensive Database on Food Additive Safety

Journal of Chemical Information and Modeling ◽

10.1021/acs.jcim.0c01147 ◽

2020 ◽

Author(s):

Shweta Singh Chauhan ◽

Deepak Kumar Sachan ◽

Ramakrishnan Parthasarathi

Keyword(s):

Food Additive ◽

Comprehensive Database

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FairBase: a comprehensive database of fungal A-to-I RNA editing

Database ◽

10.1093/database/baz018 ◽

2019 ◽

Vol 2019 ◽

Cited By ~ 5

Author(s):

Jinding Liu ◽

Dongbo Wang ◽

Yinna Su ◽

Kun Lang ◽

Rongjing Duan ◽

...

Keyword(s):

Rna Editing ◽

Comprehensive Database

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Probing gas disc physics with LISA: simulations of an intermediate mass ratio inspiral in an accretion disc

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1026 ◽

2019 ◽

Vol 486 (2) ◽

pp. 2754-2765 ◽

Cited By ~ 13

Author(s):

A M Derdzinski ◽

D D’Orazio ◽

P Duffell ◽

Z Haiman ◽

A MacFadyen

Keyword(s):

Small Deviation ◽

Compact Object ◽

Accretion Disc ◽

Mass Ratio ◽

Intermediate Mass ◽

Laser Interferometer Space Antenna ◽

Total Phase ◽

Accretion Rates ◽

Hydrodynamical Simulations ◽

And Migration

Abstract The coalescence of a compact object with a $10^{4}\hbox{--}10^{7}\, {\rm M_\odot }$ supermassive black hole (SMBH) produces mHz gravitational waves (GWs) detectable by the future Laser Interferometer Space Antenna (LISA). If such an inspiral occurs in the accretion disc of an active galactic nucleus (AGN), the gas torques imprint a small deviation in the GW waveform. Here, we present two-dimensional hydrodynamical simulations with the moving-mesh code disco of a BH inspiraling at the GW rate in a binary system with a mass ratio q = M2/M1 = 10−3, embedded in an accretion disc. We assume a locally isothermal equation of state for the gas (with Mach number $\mathcal {M}=20$) and implement a standard α-prescription for its viscosity (with α = 0.03). We find disc torques on the binary that are weaker than in previous semi-analytic toy models, and are in the opposite direction: the gas disc slows down, rather than speeds up the inspiral. We compute the resulting deviations in the GW waveform, which scale linearly with the mass of the disc. The SNR of these deviations accumulates mostly at high frequencies, and becomes detectable in a 5 yr LISA observation if the total phase shift exceeds a few radians. We find that this occurs if the disc surface density exceeds $\Sigma _0 \gtrsim 10^{2-3}\rm g\, cm^{-2}$, as may be the case in thin discs with near-Eddington accretion rates. Since the characteristic imprint on the GW signal is strongly dependent on disc parameters, a LISA detection of an intermediate mass ratio inspiral would probe the physics of AGN discs and migration.

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White Dwarf Masses and Accretion Rates of Recurrent Novae: an X-ray Perspective

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312014962 ◽

2011 ◽

Vol 7 (S281) ◽

pp. 186-189

Author(s):

Koji Mukai ◽

Jennifer L. Sokoloski ◽

Thomas Nelson ◽

Gerardo J. M. Luna

Keyword(s):

White Dwarf ◽

Cataclysmic Variables ◽

The Other ◽

X Ray ◽

Other Hand ◽

Accretion Rates

AbstractWe present recent results of quiescent X-ray observations of recurrent novae (RNe) and related objects. Several RNe are luminous hard X-ray sources in quiescence, consistent with accretion onto a near Chandrasekhar mass white dwarf. Detection of similar hard X-ray emissions in old novae and other cataclysmic variables may lead to identification of additional RNe candidates. On the other hand, other RNe are found to be comparatively hard X-ray faint. We present several scenarios that may explain this dichotomy, which should be explored further.

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