Resolving star and planet formation with ALMA

AbstractDisks around young stars are the sites of planet formation. As such, the physical and chemical structure of disks have a direct impact on the formation of planetary bodies. Outflowing winds remove angular momentum and mass and affect the disk structure and therefore potentially planet formation. Until very recently, we have lacked the facilities to provide the necessary observational tools to peer into the wind launching and planet forming regions of the young disks. Within the framework of the Resolving star formation with ALMA program, young protostellar systems are targeted with ALMA to resolve the disk formation, outflow launching and planet formation. This contribution presents the first results of the program. The first resolved images of outflow launching from a disk were recently reported towards the Class I source TMC1A (Bjerkeli et al. 2016) where we also present early evidence of grain growth (Harsono et al. 2018).

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Ice-gas interactions during planet formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316003021 ◽

2015 ◽

Vol 11 (A29A) ◽

pp. 267-270

Author(s):

Karin I. Öberg

Keyword(s):

Planet Formation ◽

Building Blocks ◽

Central Star ◽

Chemical Processes ◽

Young Stars ◽

The Past ◽

Gas Interactions ◽

Physical And Chemical ◽

Formation Efficiency

AbstractPlanets form in disks around young stars. In these disks, condensation fronts or snowlines of water, CO2, CO and other abundant molecules regulate the outcome of planet formation. Snowline locations determine how the elemental and molecular compositions of the gaseous and solid building blocks of planets evolve with distance from the central star. Snowlines may also locally increase the planet formation efficiency. Observations of snowlines have only become possible in the past couple of years. This proceeding reviews these observations as well as the theory on the physical and chemical processes in disks that affect snowline locations.

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Simulating Disk Galaxies: First Results of a Systematical Study

Proceedings of the International Astronomical Union ◽

10.1017/s1743921306005461 ◽

2006 ◽

Vol 2 (S235) ◽

pp. 114-114 ◽

Cited By ~ 2

Author(s):

Franziska Köckert ◽

Matthias Steinmetz

Keyword(s):

Angular Momentum ◽

Galaxy Formation ◽

Initial Conditions ◽

Disk Galaxies ◽

Disk Formation ◽

Numerical Resolution ◽

First Results ◽

Low Mass ◽

Current Paradigm ◽

Made In

Simulating disk galaxies within the current paradigm of galaxy formation has been a long standing problem. In comparison with observations, the simulated disks were too small and too centrally concentrated, due to a large loss of angular momentum during formation. This is known as the angular momentum catastrophe (Navarro & Benz (1991)). Recently, some progress has been made in reducing this effect by changing the cosmology, including various feedback mechanisms, improving numerical resolution and carefully selecting initial conditions with a quiet merging history after z≈2. Unfortunately, it remains unclear which of these effects, or which combination, has resulted in more realistic disk formation. In order to address this problem, we conduct a systematical study using the N-body code GADGET2 (Springel (2005)). We adopt a flat ΛCDM cosmology with Ωm=0.3, ΩΛ=0.7, Ωbar=0.04 and h=0.65. Using a softening of 0.5 kpc we find disks with a very compact unresolved gas clump in the center and a thin, extended disk (R≈10kpc) of very low mass around it.

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First Results from the Disk Eclipse Search with KELT (DESK) Survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315005931 ◽

2015 ◽

Vol 10 (S314) ◽

pp. 167-170 ◽

Cited By ~ 1

Author(s):

Joseph E. Rodriguez ◽

Joshua Pepper ◽

Keivan G. Stassun

Keyword(s):

Time Series ◽

Planet Formation ◽

Protoplanetary Disks ◽

Young Stars ◽

Circumstellar Disk ◽

Core Composition ◽

Disk Material ◽

First Results ◽

Stellar Associations

AbstractUsing time-series photometry from the Kilodegree Extremely Little Telescope (KELT) exoplanet survey, we are looking for eclipses of stars by their protoplanetary disks, specifically in young stellar associations. To date, we have discovered two previously unknown, large dimming events around the young stars RW Aurigae and V409 Tau. We attribute the dimming of RW Aurigae to an occultation by its tidally disrupted disk, with the disruption perhaps resulting from a recent flyby of its binary companion. Even with the dynamical environment of RW Aurigae, the distorted disk material remains very compact and presumably capable of forming planets. This system also shows that strong binary interactions with disks can also influence planet and core composition by stirring up and mixing materials during planet formation. We interpret the dimming of V409 Tau to be due to a feature, possibly a warp or perturbation, lying at least 10 AU from the host star in its nearly edge-on circumstellar disk.

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Accretion disks around young stars: the cradles of planet formation

Europhysics news ◽

10.1051/epn/2020104 ◽

2020 ◽

Vol 51 (1) ◽

pp. 29-32

Author(s):

Dmitry A. Semenov ◽

Richard D. Teague

Keyword(s):

Angular Momentum ◽

Accretion Disks ◽

Planet Formation ◽

Protoplanetary Disks ◽

Young Stars ◽

Dust Grains ◽

Gas Viscosity ◽

Disk Mass ◽

Disk Evolution ◽

Central Stars

Protoplanetary disks around young stars are the birth sites of planetary systems like our own. Disks represent the gaseous dusty matter left after the formation of their central stars. The mass and luminosity of the star, initial disk mass and angular momentum, and gas viscosity govern disk evolution and accretion. Protoplanetary disks are the cosmic nurseries where microscopic dust grains grow into pebbles, planetesimals, and planets.

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Unveiling the physical and chemical conditions in the young disk around L1527

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317007876 ◽

2017 ◽

Vol 13 (S332) ◽

pp. 121-123

Author(s):

M. L. R. van ’t Hoff ◽

J. J. Tobin ◽

D. Harsono ◽

E. F. van Dishoeck

Keyword(s):

Spatial Distribution ◽

Chemical Structure ◽

Protoplanetary Disks ◽

Young Stars ◽

Kinetic Temperature ◽

Temperature Structure ◽

Chemical Conditions ◽

Embedded Disks ◽

Physical And Chemical ◽

Co Emission

AbstractPlanets form in disks around young stars. The planet formation process may start when the protostar and disk are still deeply embedded within their infalling envelope. However, unlike more evolved protoplanetary disks, the physical and chemical structure of these young embedded disks are still poorly constrained. We have analyzed ALMA data for 13CO, C18O and N2D+ to constrain the temperature structure, one of the critical unknowns, in the disk around L1527. The spatial distribution of 13CO and C18O, together with the kinetic temperature derived from the optically thick 13CO emission and the non-detection of N2D+, suggest that this disk is warm enough (≳ 20 K) to prevent CO freeze-out.

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Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials ◽

10.3390/ma14071801 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1801

Author(s):

Rafał Oliwa ◽

Joanna Ryszkowska ◽

Mariusz Oleksy ◽

Monika Auguścik-Królikowska ◽

Małgorzata Gzik ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Structure ◽

Oxygen Index ◽

Polyurethane Foams ◽

Expandable Graphite ◽

Ftir Analysis ◽

Limiting Oxygen Index ◽

Peak Heat Release Rate ◽

Physical And Chemical ◽

Scanning Electron

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

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