Chondrule Formation in Radiative Shock

Ruzmaǐkina, T. V.; Ip, W. H.

doi:10.1006/icar.1994.1196

Cited by 61 publications

(44 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The same model has often been used to simulate interstellar (Shapiro & Kang 1987;Hollenbach & McKee 1989) and nebular shocks (Ruzmaikina & Ip 1994;Iida et al 2001;Miura & Nakamoto 2005.…”

Section: Post-shock Gas Structurementioning

confidence: 99%

Comprehensive Study of Thermal Desorption of Grain-surface Species by Accretion Shocks around Protostars

Miura

Yamamoto

Nomura

et al. 2017

ApJ

View full text Add to dashboard Cite

We conducted numerical simulations of the dust heating in accretion shocks induced by the interaction between the infalling envelope and the Keplerian disk surrounding a protostar, in order to investigate the thermal desorption of molecules from the dust-grain surfaces. It is thought that the surfaces of the amorphous dust grains are inhomogeneous; various adsorption sites with different binding energies should therefore exist. We assumed that the desorption energy has a Gaussian distribution and investigated the effect of the desorption energy distribution on the desorption-efficiency evaluation. We calculated the desorption fractions of the grain-surface species for wide ranges of input parameters and summarized our results in a shock diagram. The resultingshock diagram suggests that the enhanced line emissions around protostars observed using the Atacama Large Millimeter Array cannot be explained by the thermal desorption in an accretion shockif typical interstellar dust-grain sizes ( 0.1 m m ) and a single desorption energy are considered. On the other hand, if significantly smaller dust grains are the main grain-surface species carriers and the desorption energy has a Gaussian distribution, the origin of the enhanced line emission can be explained by the accretion shock heating scenario for all of the three protostars examined in this study: IRAS 04368+2557, IRAS 04365+2535, and IRAS 16293-2422. The small-grain-carrier supposition is quite reasonable when the dust grains have a power-law size distribution because the smaller grains primarily contribute to the dust-grain surface area.

show abstract

“…The same model has often been used to simulate interstellar (Shapiro & Kang 1987;Hollenbach & McKee 1989) and nebular shocks (Ruzmaikina & Ip 1994;Iida et al 2001;Miura & Nakamoto 2005.…”

Section: Post-shock Gas Structurementioning

confidence: 99%

Comprehensive Study of Thermal Desorption of Grain-surface Species by Accretion Shocks around Protostars

Miura

Yamamoto

Nomura

et al. 2017

ApJ

View full text Add to dashboard Cite

show abstract

“…The physics of the accretion shock is complex (e.g. Ruzmaikina & Ip 1994), because the temperature behind the accretion shock has to be computed. In the current study we assume that the cooling behind the shock is fast, i.e.…”

Section: Location Of the Accretion Shock And Dust Injectionmentioning

confidence: 99%

Coagulation of small grains in disks: the influence of residual infall and initial small-grain content

Dominik

Dullemond²

2008

A&A

View full text Add to dashboard Cite

Turbulent coagulation in protoplanetary disks is known to operate on a timescale far shorter than the lifetime of the disk. In the absence of mechanisms that replenish the small dust grain population, protoplanetary disks would rapidly lose their continuum opacitybearing dust. This is inconsistent with infrared observations of disks around T Tauri stars and Herbig Ae/Be stars, which are usually optically thick at visual wavelengths and show signatures of small (a 3 μm) grains. A plausible replenishing mechanism of small grains is collisional fragmentation or erosion of large dust aggregates, which model calculations predict to play an important role in protoplanetary disks. If optically thick disks are to be seen as proof for ongoing fragmentation or erosion, then alternative explanations for the existence of optically thick disks must be studied carefully. In this study we explore two scenarios. First, we study the effect of residual, low-level infall of matter onto the disk surface. We find that infall rates as low as 10 −11 M /yr can, in principle, replenish the small grain population to a level that keeps the disk marginally optically thick. However, it remains to be seen if the assumption of such an inflow is realistic for star+disk systems at the age of several Myrs, at which winds and jets are expected to have removed any residual envelope. The effectiveness of even a low level infall can be understood by the strongly non-linear behavior of the coagulation equation: a high, fine-grain, dust density at any given time leads to very fast, effective removal of these small grains, while a low fine-grain density lasts for a far longer time. We then consider a second scenario in which, during the buildup phase of the disk, an intermediate fine-grain dust abundance is generated that is sufficiently low to ensure longevity of the state yet sufficiently high for the disk to remain optically thick. While our models confirm that such an "initial condition" can be constructed, we argue that these special initial conditions cannot be achieved during the disk build-up phase. In summary, fragmentation or erosion still appear to be the most promising processes to explain the abundant presence of small grains in old disks.

show abstract

“…Since the models based on heating in shock waves make fewer assumptions on the physical environment, we will focus on these events, which have been investigated by a large amount of detailed modelling, e.g. Hood & Horanyi (1991, Ruzmaikina & Ip (1994), Hood (1998), Desch & Connolly (2002), Miura et al (2002), and Miura & Nakamoto (2005, 2006. Ciesla & Hood (2002) and Ciesla et al (2004) developed gas-particle suspension models with significant heating via radiation from the other chondrule-sized particles.…”

Section: Introductionmentioning

confidence: 99%

“…In the literature several mechanisms have been suggested to explain the shock waves, i.e. accretion shocks on the surface of the protoplanetary disc (Ruzmaikina & Ip 1994), infall of clumps of gas onto the nebulae (Tanaka et al 1998), bow shocks produced by planetesimals on eccentric orbits (Weidenschilling et al 1998), and X-ray flares from the young Sun . Clearly, all these scenarios A&A 541, A107 (2012) give only a simplified picture of the numerous interactions between radiation field, and gas, and dust particles.…”

Section: Introductionmentioning

confidence: 99%

Formation of chondrules in radiative shock waves

Joham

Dorfi

2012

A&A

View full text Add to dashboard Cite

Context. The formation of chondrules in the protoplanetary nebulae causes many questions concerning the formation process, the source of energy for melting the rims, and the composition of the origin material. Aims. The aim of this work is to explore the heating of the chondrule in a single precursor as is typical for radiation hydrodynamical shock waves. We take into account the gas-particle friction for the duration of the shock transition and calculate the heat conduction into the chondrules. These processes are located in the protoplanetary nebulae at a region around 2.5 AU, which is considered to be the most likely place of chondrule formation. The present models are a first step towards computing radiative shock waves occurring in a particle-rich environment. Methods. We calculated the shock waves using one-dimensional, time-independent equations of radiation hydrodynamics involving realistic gas and dust opacities and gas-particle friction. The evolution of spherical chondrules was followed by solving the heat conduction equation on an adaptive grid. Results. The results for the shock-heating event are consistent with the cosmochemical constraints of chondrule properties. The calculations yield a relative narrow range for density or temperature to meet the requested heating rates of R > 10 4 K h −1 as extracted from cosmochemical constraints. Molecular gas, opacities with dust, and a protoplanetary nebula with accretion are necessary requirements for a fast heating process. The thermal structure in the far post-shock region is not fully consistent with experimental constraints on chondrule formation since the models do not include additional molecular cooling processes.

show abstract

Chondrule Formation in Radiative Shock

Cited by 61 publications

References 0 publications

Comprehensive Study of Thermal Desorption of Grain-surface Species by Accretion Shocks around Protostars

Comprehensive Study of Thermal Desorption of Grain-surface Species by Accretion Shocks around Protostars

Coagulation of small grains in disks: the influence of residual infall and initial small-grain content

Formation of chondrules in radiative shock waves

Contact Info

Product

Resources

About