BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Elemental chemistry in the inner regions of protoplanetary discs DTSTART;VALUE=DATE-TIME:20200515T122000Z DTEND;VALUE=DATE-TIME:20200515T124000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-39@meetings.aip.de DESCRIPTION:Speakers: Pooneh Nazari (Leiden University)\nElemental abundan ce ratios in the inner regions of protoplanetary discs are important for s etting the composition of exoplanets\, but are likely not to represent the bulk composition of the star's parental cloud. Abundance differences are expected to be driven by the differential transport of chemical species in solid and gaseous form: elements which are mainly concentrated in species with high melting points may be either over-represented in the inner disc (due to efficient inward radial drift of icy grains) or else under-repres ented (if such grains become trapped in the outer disc).\n\nHere I explore a new observational window for determining the relative abundances of C\, N and Si in the inner disc through examination of ultraviolet emission li nes generated by material accreting onto the central star via an accretion column and shock. I use CLOUDY to calculate the resulting ratios of CIV\, NV and SiIV lines and how these vary with input elemental abundance ratio s. I conclude that such line ratios provide a sensitive probe of abundance s in the inner disc and describe the constraints provided by existing HST spectroscopic observations of T Tauri stars.\n\nhttps://meetings.aip.de/ev ent/1/contributions/39/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/39/ END:VEVENT BEGIN:VEVENT SUMMARY:Locating the water snowline in protoplanetary disks using the chem ical tracer H13CO+ DTSTART;VALUE=DATE-TIME:20200515T115500Z DTEND;VALUE=DATE-TIME:20200515T121500Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-62@meetings.aip.de DESCRIPTION:Speakers: Margot Leemker (Leiden University)\nSnowlines\, in p articular the water snowline\, are important for the formation of planets in protoplanetary disks. However\, locating the water snowline directly is challenging. Firstly\, due to the proximity of the water snowline to the host star. But ALMA can now resolve this region for the first time. Second ly\, due to the absorption of water in the Earth's atmosphere. A chemical tracer\, HCO+\, provides a solution to the latter problem. HCO+ is destroy ed by gas-phase water\, therefore no HCO+ is expected to be present when w ater desorps from the grains. It has already been shown by van 't Hoff et al. (2018) that the optically thin isotopologue\, H13CO+\, acts as a trace r of the water snowline in the envelope around a Class 0 object. We invest igate whether this also works in Class 2 objects where planets form. The H CO+ abundance is modeled using our small chemical network and using the de nsity and temperature structure from a DALI model. The expected emission i s modeled for different transitions of H13CO+. I will discuss how well H13 CO+ traces the water snowline in disks. We can already confirm that the HC O+ abundance drops when water desorps from the grains and I will discuss w hat observations are needed to locate the water snowline with ALMA.\n\nhtt ps://meetings.aip.de/event/1/contributions/62/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/62/ END:VEVENT BEGIN:VEVENT SUMMARY:Predicting the Observational Signature of Migrating Neptune-sized Planets in Low-viscosity Disks DTSTART;VALUE=DATE-TIME:20200515T113000Z DTEND;VALUE=DATE-TIME:20200515T115000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-33@meetings.aip.de DESCRIPTION:Speakers: Philipp Weber (Niels Bohr Institute)\nThe migration of planetary cores embedded in a protoplanetary disk is an important mecha nism within planet-formation theory\, relevant for the architecture of pla netary systems. Consequently\, planet migration is actively discussed\, ye t often results of independent theoretical or numerical studies are uncons trained due to the lack of observational diagnostics designed in light of planet migration. In this work we follow the idea of inferring the migrati on behavior of embedded planets by means of the characteristic radial stru ctures that they imprint in the disk’s dust density distribution. We run hydrodynamical multifluid simulations of gas and several dust species in a locally isothermal α-disk in the low-viscosity regime (α = 10-5) and i nvestigate the obtained dust structures. In this framework\, a planet of r oughly Neptune mass can create three (or more) rings in which dust accumul ates. We find that the relative spacing of these rings depends on the plan et’s migration speed and direction. By performing subsequent radiative t ransfer calculations and image synthesis we show that—always under the c ondition of a near-inviscid disk—different migration scenarios are\, in principle\, distinguishable by long-baseline\, state-of-the-art Atacama La rge Millimeter/submillimeter Array observations.\n\nhttps://meetings.aip.d e/event/1/contributions/33/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/33/ END:VEVENT BEGIN:VEVENT SUMMARY:Measuring dust-gas coupling via the gas rotation curve DTSTART;VALUE=DATE-TIME:20200514T075000Z DTEND;VALUE=DATE-TIME:20200514T081000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-19@meetings.aip.de DESCRIPTION:Speakers: Giovanni Rosotti (Leiden University)\nALMA is showin g that most proto-planetary discs are highly sub-structured and that the m ost frequent structure consists in azimuthally symmetric "gaps and rings". Rings have attracted a lot of attention since they might be the signature of young planets. But rings are extremely important for another reason: t hey provide us with a privileged window inside disc physics. Indeed\, as s hown by the DSHARP team\, their finite dust width shows that there must be some level of dust diffusion\, or else the dust would only collect at the pressure maximum. However\, the DSHARP team was only able to place a lowe r limit\, and not to measure\, the amount of diffusion\, because they did not have information on the gas distribution. I will show how the analysis of the gas rotation curve\, another breakthrough enabled by ALMA observat ions of molecular lines\, is a powerful way to measure the width of rings in the gas and therefore allows us to measure the dust-gas coupling\, whic h controls the dust ring width. Formally\, the relevant parameter is the r atio between the Shakura-Sunyaev α and the dust Stokes number St. I will also discuss the impact of the disc 3D structure on this analysis and show that the measurement of ring width is robust towards the details of the v ertical structure. At the moment\, there are only two objects with good en ough S/N to perform these measurements. In these objects\, I will report g as widths larger than in the dust\, consistently with the idea of dust tra pping. I will show how the data point to a relatively high degree of dust- gas coupling (typical α/St ~ 0.1). Scenarios with very low levels of turb ulence and high levels of grain growth can therefore be rejected. Future c onstraints on the dust grain size in the rings will help in breaking the d egeneracy between St and alpha.\n\nhttps://meetings.aip.de/event/1/contrib utions/19/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/19/ END:VEVENT BEGIN:VEVENT SUMMARY:Doppler flips and wiggles in long baseline observations of protopl anetary disks with ALMA DTSTART;VALUE=DATE-TIME:20200514T072500Z DTEND;VALUE=DATE-TIME:20200514T074500Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-55@meetings.aip.de DESCRIPTION:Speakers: Sebastián Pérez (Universidad de Santiago de Chile) \nProtoplanets and circumplanetary disks are elusive yet they are cornerst ones to the most popular interpretations for observed protoplanetary disk structures. The gaseous velocity field also bears the imprint of planet– disk interactions\, with non-Keplerian fine structure in the molecular-lin e channel maps (e.g.\, wiggles or kinks). Such features could in principle be connected to the perturber by comparison with hydrodynamical simulatio ns\, however\, there is a more direct way of pinpointing the protoplanet ’s location: identifying the place where the non-Keplerian velocities un dergo an abrupt sign reversal\, a.k.a. a "Doppler flip"\, in velocity cent roid maps. In this talk\, I will discuss the kinematic signatures of plane t formation and present recent observations of the young disk in HD 100546 in CO emission and dust continuum. The high-resolution 1.3 mm continuum o bservation reveals fine radial and azimuthal substructures in the form of a complex maze of ridges and trenches sculpting a dust ring. Near these du st structures\, we pick up a conspicuous Doppler flip. The 12CO channel ma ps are modulated by wiggles that deviate from Keplerian kinematics and whi ch are somewhat connected to the Doppler flip signal.\n\nhttps://meetings. aip.de/event/1/contributions/55/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/55/ END:VEVENT BEGIN:VEVENT SUMMARY:Measuring 3D Velocities in Planet Forming Disks DTSTART;VALUE=DATE-TIME:20200514T070000Z DTEND;VALUE=DATE-TIME:20200514T072000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-15@meetings.aip.de DESCRIPTION:Speakers: Richard Teague (Center for Astrophysics | Harvard & Smithsonian)\nI will present a novel method to extract azimuthally average d 3D velocity profiles from ALMA data. Application of this to the well stu died source HD 163296 reveals a highly dynamical disk\, hosting large flow structures indicative of meridional flows likely driven by three embedded protoplanets. These flows provide an efficient transport mechanism of vol atile-rich gas in the disk atmosphere towards the planet-forming midplane. In addition\, we find tentative evidence of a slow disk wind in the outer 100 au of the disk\, like connected to the previously detected large scal e wind described in Klaassen et al. (2013). I will further demonstrate how application of this method to multiple molecular species will allow us to map the dynamical structure of a protoplanetary disks in the (r\, z) plan e\, allowing us to directly search for characteristic flow structures whic h will help us to distinguish between potentially active instabilities. I will end with an outlook to how extensions of these methods can be used to search for embedded planets by searching for localized deviations from th e background rotation.\n\nhttps://meetings.aip.de/event/1/contributions/15 / LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/15/ END:VEVENT BEGIN:VEVENT SUMMARY:What can we learn from ALMA polarimetric observations of protoplan etary disks? DTSTART;VALUE=DATE-TIME:20200512T142500Z DTEND;VALUE=DATE-TIME:20200512T144500Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-14@meetings.aip.de DESCRIPTION:Speakers: Akimasa Kataoka (National Astronomical Observatory o f Japan)\nPolarimetric observations of protoplanetary disks at millimeter wavelengths have been dramatically developing owing to its high-sensitivit y and high-resolution observations with ALMA. However\, the mechanisms of the polarization are under discussion. The proposed mechanisms so far are the self-scattering and the grain alignment\, but the alignment directions are possibly with magnetic fields\, with radiation fields\, or with gas-d rag directions. In this talk\, I first review the possible mechanisms that may produce the millimeter polarization\, and then present the case studi es of different disks. On the lopsided disk of HD 142527\, we found that t he magnetic fields are dominated by the toroidal components at least in th e south regions. On the ring-gap disk of HD 163296\, by modeling the self- scattering polarization\, we found that the dust scale height is lower in the inner regions\, which indicates the low turbulence of gas in the inner disk and is consistent with the concept of magnetic dead zone. I also dis cuss possible constraints on the grain dynamics on AS 209 and HL Tau by mo deling the gas-flow aligned dust grains.\n\nhttps://meetings.aip.de/event/ 1/contributions/14/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/14/ END:VEVENT BEGIN:VEVENT SUMMARY:ALMA chemical survey of Disk-Outflow sources in Taurus DTSTART;VALUE=DATE-TIME:20200512T145000Z DTEND;VALUE=DATE-TIME:20200512T151000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-18@meetings.aip.de DESCRIPTION:Speakers: Antonio Garufi ()\nALMA-DOT is a small campaign devo ted to the chemical characterization of disk-outflow sources in Taurus. Th e sample currently consists of six Class I sources known to drive powerful outflows. The high angular resolution and sensitivity of ALMA allowed us to characterize their chemical composition by separating the disk emission from the outflow and envelope contamination. Six molecules - from carbon monoxyde to the simple organic formaldehyde and methanol - have been surve yed in each target. I present the results of the survey\, shedding light o n (i) the timescale for the formation of dust and gas sub-structures\, (ii ) the morphological interplay of dust and gas\, (iii) the role of disk-fee ding filaments\, (iv) the distribution and formation mechanism of simple o rganic molecules\, and (v) the chemical composition of molecular outflows. Young sources like those probed by ALMA-DOT offer the best laboratory to study how soon are planets formed and how are complex molecules delivered to the (assembling) planetary atmospheres.\n\nhttps://meetings.aip.de/even t/1/contributions/18/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/18/ END:VEVENT BEGIN:VEVENT SUMMARY:The polarizing puzzle of dusty disks DTSTART;VALUE=DATE-TIME:20200512T140000Z DTEND;VALUE=DATE-TIME:20200512T142000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-10@meetings.aip.de DESCRIPTION:Speakers: Gesa H.-M. Bertrang (MPIA)\nFrom a theoretical point -of-view\, magnetic fields are crucial to the evolution of planet-forming disks. However\, profound observational constraints are pending. Presently \, the number of cutting-edge polarization observations presenting inconcl usive data increases continuously. In very recent years\, polarization at mm-wavelengths\, the classical tracer of magnetic fields\, emerged as high ly ambiguous\, and the pressing demand for comprehensive tools to analyze these new observations is growing.\n\nI will present an overview on the so urces of continuum polarization with focus on the impact of grain alignmen t\, scattering\, and grain porosity on the polarization measurement – as well as a potential solution to this dusty ambiguousness\, linearly polar ized gas emission.\n\nhttps://meetings.aip.de/event/1/contributions/10/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/10/ END:VEVENT BEGIN:VEVENT SUMMARY:Protoplanetary Disk Chemodynamics as a Scale for Weighing Young St ars and Planets DTSTART;VALUE=DATE-TIME:20200512T075000Z DTEND;VALUE=DATE-TIME:20200512T081000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-41@meetings.aip.de DESCRIPTION:Speakers: Patrick Sheehan (Northwestern University)\nMuch of o ur understanding of star and planet formation hinges on the accuracy of st ellar masses and ages derived from pre-main sequence evolutionary track mo dels. Consequently\, errors in evolutionary track models could propagate t hrough much of our understanding of star and planet formation. Moreover\, there remain few constraints on pre-main sequence evolutionary tracks owin g in large part to the lack of pre-main sequence stars with precisely meas ured masses. Fortunately\, Keplerian rotation in protoplanetary disks pro vides an avenue towards directly measuring the masses of young stars\, and therefore could provide large samples of well measured masses with which to constrain evolutionary tracks. I will present my efforts using radiativ e transfer forward modeling of ALMA spectral line observations\, in conjun ction with precise distance measurements from Gaia that are used to break the stellar mass-distance degeneracy\, to directly measure pre-main sequen ce stellar masses with precisions as high as 2%. I will also present effor ts to extend these methods to measure stellar masses for embedded protosta rs\, where the traditional method of estimating masses from evolutionary t racks can be impossible\, as well as an attempt to directly measure the ma ss of a young purported protoplanet.\n\nhttps://meetings.aip.de/event/1/co ntributions/41/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Observed sizes of planet-forming disks trace viscous spreading DTSTART;VALUE=DATE-TIME:20200512T072500Z DTEND;VALUE=DATE-TIME:20200512T074500Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-24@meetings.aip.de DESCRIPTION:Speakers: L. Trapman (Leiden University)\nThe evolution of pro toplanetary disks is set by the conservation of angular momentum\, where t he accretion of material onto the central star is balanced by viscous expa nsion of the outer disk or by disk winds extracting angular momentum witho ut changing the disk size. Studying the time evolution of disk sizes allow s us therefore to distinguish between viscous stresses or disk winds as th e main mechanism of disk evolution. Observationally\, estimates of the dis k gaseous outer radius are based on the extent of the CO rotational emissi on\, which\, during the evolution\, is also affected by the changing physi cal and chemical conditions in the disk.\nWe have used physical-chemical m odels to study how the extent of the CO emission changes with time in a vi scously expanding disk. We find that the gas outer radius ($R_{\\rm CO\,\\ 90\\%}$) measured from our models matches the expectations of a viscously spreading disk: $R_{\\rm CO\,\\ 90\\%}$ increases with time and for a giv en time $R_{\\rm CO\,\\ 90\\%}$ is larger for a disk with a higher viscosi ty $\\alpha_{\\rm visc}$. However\, in the extreme case where the disk mas s is low ($ \\leq 10^{-4}\\ \\mathrm{M}_{\\odot}$) and $\\alpha_{\\rm visc }$ is high ($\\geq 10^{-2}$)\, $R_{\\rm CO\,\\ 90\\%}$ will instead decrea se with time as a result of CO photodissociation in the outer disk. \nWe f ind that most observed gas outer radii in Lupus can be explained using a v iscously evolving disk that starts out small $(\\simeq 10\\ \\mathrm{AU})$ and has a low viscosity $(\\alpha_{\\rm visc} = 10^{-4} - 10^{-3})$.\n\nh ttps://meetings.aip.de/event/1/contributions/24/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/24/ END:VEVENT BEGIN:VEVENT SUMMARY:Disk Spreading and Surface Accretion Flows in Protoplanetary Disks DTSTART;VALUE=DATE-TIME:20200512T070000Z DTEND;VALUE=DATE-TIME:20200512T072000Z DTSTAMP;VALUE=DATE-TIME:20240704T115529Z UID:indico-contribution-10-7@meetings.aip.de DESCRIPTION:Speakers: Joan Najita (National Optical-Infrared Astronomy Res earch Laboratory)\nDespite its importance for star and planet formation\, the physical process(es) that drive disk accretion remain frustratingly un clear. The magnetorotational instability is questioned both theoretically and observationally and disk winds are increasingly invoked. I will descri be how the evolution of gas disk sizes from Class I to Class II indicates that some mechanism produces significant disk spreading (i.e.\, angular mo mentum transport within the disk) during the Class II phase. I will also s how results from high resolution mid-infrared spectroscopy of a Class I so urce that may provide evidence for an alternative angular momentum transpo rt mechanism\, “surface accretion flows\,” which have been reported in MHD simulations of magnetized disks.\n\nhttps://meetings.aip.de/event/1/c ontributions/7/ LOCATION:Leibniz Institute for Astrophysics Potsdam (AIP) Lecture Hall URL:https://meetings.aip.de/event/1/contributions/7/ END:VEVENT END:VCALENDAR