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During the formation of a star, material is ejected along powerful jets that impact the ambient material. This outflow regulates star formation by e.g. inducing turbulence and heating the surrounding gas. Understanding the associated shocks…

HD100546 represents a particularly interesting target to study dynamical planet-disk interactions as various features have been observed in both the dust and gas that provide direct and indirect evidence for ongoing planet formation. In…

We carry out the first robust numerical simulation of accretion flows on a weakly magnetized neutron star using Smoothed Particle Hydrodynamics (SPH). We follow the Two-Component Advective Flow (TCAF) paradigm for black holes, and focus…

High Energy Astrophysical Phenomena · Physics 2019-03-20 Ayan Bhattacharjee , Sandip K. Chakrabarti

Context. While it is generally assumed that Class II sources evolve largely in isolation from their environment, many still lie close to molecular clouds and may continue to interact with them. This may result in late accretion of material…

Context. "Snow lines", marking regions where abundant volatiles freeze out onto the surface of dust grains, play an important role for planet growth and bulk composition in protoplanetary disks. They can already be observed in the envelopes…

Astrophysics of Galaxies · Physics 2016-06-08 S. Anderl , S. Maret , S. Cabrit , A. Belloche , A. J. Maury , Ph. André , C. Codella , A. Bacmann , S. Bontemps , L. Podio , F. Gueth , E. Bergin

Planet-disc interactions build up local pressure maxima that may halt the radial drift of protoplanetary dust, and pile it up in rings and crescents. ALMA observations of the HD135344B disc revealed two rings in the thermal continuum…

The physical and chemical conditions in Class 0/I protostars are fundamental in unlocking the protostellar accretion process and its impact on planet formation. The aim is to determine which physical components are traced by different…

We present results of the first global magnetohydrodynamic (MHD) simulations of accretion disks fed by Roche lobe overflow, including vertical stratification, in order to investigate the roles of spiral shocks, magnetorotational instability…

High Energy Astrophysical Phenomena · Physics 2020-12-08 Patryk Pjanka , James M. Stone

Radial transport of particles, elements and fluid driven by internal stresses in three-dimensional (3D) astrophysical accretion disks is an important phenomenon, potentially relevant for the outward dust transport in protoplanetary disks,…

High Energy Astrophysical Phenomena · Physics 2017-03-15 Alexander A. Philippov , Roman R. Rafikov

One of the early hypotheses about the origin of FUOR outbursts explains them by the fall of gas clumps from the remnants of protostellar clouds onto protoplanetary disks surrounding young stars (Hartmann and Kenyon 1985). To calculate the…

Solar and Stellar Astrophysics · Physics 2023-08-10 Tatiana V. Demidova , Vladimir P. Grinin

We present high-resolution optical spectra of 15 objects near or below the sub-stellar limit in the Upper Scorpius and $\rho$ Ophiuchus star-forming regions. These spectra, obtained with the HIRES instrument on the Keck I telescope, are…

Astrophysics · Physics 2009-11-07 Ray Jayawardhana , Subhanjoy Mohanty , Gibor Basri

We present high-resolution ($\sim$0.05"; 8 au) dust continuum and molecular line observations toward the Class I protostellar system IRAS 04169+2702 in the Taurus B213 region, as part of the ALMA Large Program Early Planet Formation in…

The application of silicon monoxide (SiO) as a shock tracer arises from its propensity to occur in the gas phase as a result of shock-induced phenomena, including outflow activity and interactions between molecular clouds and expanding HII…

Astrophysics of Galaxies · Physics 2023-11-29 W. -J. Kim , J. S. Urquhart , V. S. Veena , G. A. Fuller , P. Schilke , K-T Kim

Water and methanol are key components of interstellar ices and gas in star- and planet-forming regions, but direct observations of water in low-mass protostars are challenging due to atmospheric absorption. We present high-resolution (R =…

ALMA surveys have shown that CO emission in protoplanetary disks is much fainter than expected. Accordingly, CO-based gas masses and gas/dust ratios are orders of magnitude lower than previously thought. This may be explained either as fast…

Solar and Stellar Astrophysics · Physics 2019-10-23 A. Miotello , S. Facchini , E. F. van Dishoeck , P. Cazzoletti , L. Testi , J. P. Williams , M. Ansdell , S. van Terwisga , N. van der Marel

The cold outer regions of protoplanetary disks are expected to contain a midplane-centered layer where gas-phase CO molecules freeze out and their overall abundance is low. The layer then manifests itself as a void in the channel maps of CO…

Earth and Planetary Astrophysics · Physics 2025-08-13 O. Chrenko , S. Casassus , R. O. Chametla

As part of the ALMA Large Program "Early Planet Formation in Embedded Disks" (eDisk), 12CO (2 - 1) was observed towards 19 nearby low-mass protostars. Of these objects, 15 sources are found to show molecular outflow emission. Based on their…

High spatial resolution CO observations of mid-inclination (30-75{\deg}) protoplanetary disks offer an opportunity to study the vertical distribution of CO emission and temperature. The asymmetry of line emission relative to the disk major…

It is believed that protostellar accretion disks to be formed from nearly ballistic infall of the molecular matters in rotating core collapse. Collisions of these infalling matters lead to formation of strong supersonic shocks, which if…

Astrophysics of Galaxies · Physics 2015-05-27 Mohsen Nejad-Asghar

We present synthetic ALMA observations of Keplerian, protostellar discs in the Class 0 stage studying the emission of molecular tracers like $^{13}$CO, C$^{18}$O, HCO$^+$, H$^{13}$CO$^+$, N$_2$H$^+$, and H$_2$CO. We model the emission of…

Solar and Stellar Astrophysics · Physics 2016-04-20 D. Seifried , Á. Sánchez-Monge , S. Walch , R. Banerjee