Structure of planet-forming disks: multi-wavelength polarization diagnostics

The study of dynamic processes that drive the evolution of planet-forming disks is fundamental to understand the origin and diversity of planetary systems. This requires observations at high spatial resolution and sensitivity, which nowadays typically reveal intriguing disk substructures including gaps, rings, spirals, and shadows. This thesis investigates the capability of polarization observations at multiple wavelengths to trace the earliest stages of planet formation. In-depth radiative transfer calculations are carried out in order to link numerical simulations of dust and gas evolution in disks with their observational indicators. This approach demonstrates that measuring polarization is a powerful tool to identify the shaping effects that possible embedded planets have on the density distribution of different dust grain sizes. On the observational part, this work presents several case studies of individual planet-forming disks that were observed with polarimetric imaging by the VLT/SPHERE instrument and subsequently modeled to quantify their structure. A particular focus is the characterization of spiral and ring/gap structures in the context of dust growth, planet-disk interactions, and dust dynamics near ice lines. Furthermore, a modeling study of marginally gravitationally unstable disks is presented to study the influence of the disk self-gravity on the shape and contrast of planet-induced spiral arms in scattered light images. Additionally, it is demonstrated that polarized emission of disks at millimeter wavelengths can be caused by self-scattered thermal dust emission. It is shown that the latter is a viable method to constrain grain properties and identify dust concentrations of different origin. New ALMA observations are presented that offer the first look at a dust trap in polarized scattered light in the sub-millimeter range

Impact of duplicate gene copies on phylogenetic analysis and divergence time estimates in butterflies

<p>Abstract</p> <p>Background</p> <p>The increase in availability of genomic sequences for a wide range of organisms has revealed gene duplication to be a relatively common event. Encounters with duplicate gene copies have consequently become almost inevitable in the context of collecting gene sequences for inferring species trees. Here we examine the effect of incorporating duplicate gene copies evolving at different rates on tree reconstruction and time estimation of recent and deep divergences in butterflies.</p> <p>Results</p> <p>Sequences from ultraviolet-sensitive (<it>UVRh</it>), blue-sensitive (<it>BRh</it>), and long-wavelength sensitive (<it>LWRh</it>) opsins,<it>EF-1α </it>and <it>COI </it>were obtained from 27 taxa representing the five major butterfly families (5535 bp total). Both <it>BRh </it>and <it>LWRh </it>are present in multiple copies in some butterfly lineages and the different copies evolve at different rates. Regardless of the phylogenetic reconstruction method used, we found that analyses of combined data sets using either slower or faster evolving copies of duplicate genes resulted in a single topology in agreement with our current understanding of butterfly family relationships based on morphology and molecules. Interestingly, individual analyses of <it>BRh </it>and <it>LWRh </it>sequences also recovered these family-level relationships. Two different relaxed clock methods resulted in similar divergence time estimates at the shallower nodes in the tree, regardless of whether faster or slower evolving copies were used, with larger discrepancies observed at deeper nodes in the phylogeny. The time of divergence between the monarch butterfly <it>Danaus plexippus </it>and the queen <it>D. gilippus </it>(15.3–35.6 Mya) was found to be much older than the time of divergence between monarch co-mimic <it>Limenitis archippus </it>and red-spotted purple <it>L. arthemis </it>(4.7–13.6 Mya), and overlapping with the time of divergence of the co-mimetic passionflower butterflies <it>Heliconius erato </it>and <it>H. melpomene </it>(13.5–26.1 Mya). Our family-level results are congruent with recent estimates found in the literature and indicate an age of 84–113 million years for the divergence of all butterfly families.</p> <p>Conclusion</p> <p>These results are consistent with diversification of the butterfly families following the radiation of angiosperms and suggest that some classes of opsin genes may be usefully employed for both phylogenetic reconstruction and divergence time estimation.</p

Evolution of protoplanetary disks from their taxonomy in scattered light: Group I vs. Group II

High-resolution imaging reveals a large morphological variety of protoplanetary disks. To date, no constraints on their global evolution have been found from this census. An evolutionary classification of disks was proposed based on their IR spectral energy distribution, with the Group I sources showing a prominent cold component ascribed to an earlier stage of evolution than Group II. Disk evolution can be constrained from the comparison of disks with different properties. A first attempt of disk taxonomy is now possible thanks to the increasing number of high-resolution images of Herbig Ae/Be stars becoming available. Near-IR images of six Group II disks in scattered light were obtained with VLT/NACO in Polarimetric Differential Imaging, which is the most efficient technique to image the light scattered by the disk material close to the stars. We compare the stellar/disk properties of this sample with those of well-studied Group I sources available from the literature. Three Group II disks are detected. The brightness distribution in the disk of HD163296 indicates the presence of a persistent ring-like structure with a possible connection with the CO snowline. A rather compact (less than 100 AU) disk is detected around HD142666 and AK Sco. A taxonomic analysis of 17 Herbig Ae/Be sources reveals that the difference between Group I and Group II is due to the presence or absence of a large disk cavity (larger than 5 AU). There is no evidence supporting the evolution from Group I to Group II. Group II are not evolved version of the Group I. Within the Group II disks, very different geometries (both self-shadowed and compact) exist. HD163296 could be the primordial version of a typical Group I. Other Group II, like AK Sco and HD142666, could be smaller counterpart of Group I unable to open cavities as large as those of Group I.Comment: 16 pages, 7 figures, published by A&

Detection of Sharp Symmetric Features in the Circumbinary Disk Around AK Sco

The Search for Planets Orbiting Two Stars (SPOTS) survey aims to study the formation and distribution of planets in binary systems by detecting and characterizing circumbinary planets and their formation environments through direct imaging. With the SPHERE Extreme Adaptive Optics instrument, a good contrast can be achieved even at small (<300 mas) separations from bright stars, which enables studies of planets and disks in a separation range that was previously inaccessible. Here, we report the discovery of resolved scattered light emission from the circumbinary disk around the well-studied young double star AK Sco, at projected separations in the ~13--40 AU range. The sharp morphology of the imaged feature is surprising, given the smooth appearance of the disk in its spectral energy distribution. We show that the observed morphology can be represented either as a highly eccentric ring around AK Sco, or as two separate spiral arms in the disk, wound in opposite directions. The relative merits of these interpretations are discussed, as well as whether these features may have been caused by one or several circumbinary planets interacting with the disk.Comment: 10 pages, 3 figures, accepted for publication in ApJ Letters. Minor (proof-level) corrections implemented in this versio

Solving grain size inconsistency between ALMA polarization and VLA continuum in the Ophiuchus IRS 48 protoplanetary disk

The protoplanetary disk around Ophiuchus IRS 48 shows an azimuthally asymmetric dust distribution in (sub-)millimeter observations, which is interpreted as a vortex, where millimeter/centimeter-sized particles are trapped at the location of the continuum peak. In this paper, we present 860 $\mu$m ALMA observations of polarized dust emission of this disk. The polarized emission was detected toward a part of the disk. The polarization vectors are parallel to the disk minor axis, and the polarization fraction was derived to be $1-2$\%. These characteristics are consistent with models of self-scattering of submillimeter-wave emission, which indicate a maximum grain size of $\sim100$ $\mu$m. However, this is inconsistent with the previous interpretation of millimeter/centimeter dust particles being trapped by a vortex. To explain both, ALMA polarization and previous ALMA and VLA observations, we suggest that the thermal emission at 860 $\mu$m wavelength is optically thick ($\tau_{\rm abs}\sim7.3$) at the dust trap with the maximum observable grain size of $\sim100$ $\mu$m rather than an optically thin case with $\sim$ cm dust grains. We note that we cannot rule out that larger dust grains are accumulated near the midplane if the 860 $\mu$m thermal emission is optically thick.Comment: 22 pages, 17 figures, accepted for publication in Ap

A Graduação em Fisioterapia na Universidade Estadual do Centro-Oeste

A graduação na área da saúde vem sofrendo alterações constantes. Durante a década de 90, a Reforma Sanitária no Brasil estabeleceu novas estratégias para todos os cursos envolvidos na área de saúde. Na fisioterapia, uma das principais mudanças foi no sentido de enfatizar o processo ‘saúdedoença’ dentro de uma visão mais ampla, preconizando não só a cura e a reabilitação da doença, mas também a promoção da saúde e, principalmente, a prevenção da doença. A Universidade Estadual do Centro-Oeste (UNICENTRO), fortalecendo seu papel de servidora pública de ensino superior, propôs a implantação do curso de fi sioterapia procurando suprir a escassez de fi sioterapeutas em sua área de abrangência. O curso teve início no ano de 2000, com uma matriz curricular que contemplava as propostas de Diretrizes Nacionais para Cursos de Graduação em Fisioterapia de 1998. O Departamento de Fisioterapia (DEFISIO) vem reformulando a matriz curricular para sua adequação conforme as novas normas estabelecidas em consonância com o Ministério da Saúde para também contemplar modelo de assistência à saúde vigente. Visando propor ações e estratégias que estimulem um aumento na qualidade de ensino e fomentem a pesquisa científi ca na área, para posterior utilização na atuação profi ssional, foi realizada uma análise da trajetória do referido curso para entender a formação acadêmica do graduado em fi sioterapia na UNICENTRO. A coleta de dados teve seu embasamento na literatura existente, leis e pareceres emitidos por órgãos governamentais e em documentos que constam nos arquivos da Instituição

Compound drivers behind new record high temperatures and surface melt at the Antarctic Peninsula in February 2022

The Antarctic Peninsula (AP) experienced a new extreme warm event and record high surface melt inFebruary 2022, rivaling the recent temperature records from 2015 and 2020, and contributing to analarming series of extreme warm events there. The northern/northwestern AP was directly impactedby an intense atmospheric river (AR) bringing anomalous heat and rainfall, while AR-enhanced foehneffect further warmed its northeastern side. The event was triggered by multiple large-scaleatmospheric circulation patterns linking the AR formation to tropical convection anomalies andstationary Rossby waves, with anomalous Amundsen Sea low and record-breaking blocking high. Thecascade of impacts culminated in widespread and intensive surface melt across the AP. The event wasstatistically attributed to global warming. Increasing frequency of such events can undermine thestability of the AP ice shelves, with multiple local to global impacts, including acceleration of the APice mass loss and changes in sensitive ecosystems.Fil: Gorodetskaya, Irina. Universidad de Porto; PortugalFil: Durán Alarcón, Claudio. Universidade de Aveiro. Centro de Estudos Do Ambiente E Do Mar.; PortugalFil: Gonzalez Herrero, Sergi. Universidade de Aveiro. Centro de Estudos Do Ambiente E Do Mar.; PortugalFil: Clem, Kyle. Universidad de Porto. Facultad de Ciências. Centro Interdisciplinar de Investigação Marinha E Ambiental.; PortugalFil: Rodriguez Imazio, Paola Carolina. Ministerio de Defensa. Secretaria de Planeamiento. Servicio Meteorológico Nacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Santos, Christophe Leroy Dos. European Southern Observatory Chile.; ChileFil: Campos, Diego Rodrigo. European Southern Observatory Chile.; ChileFil: Zou, Xun. Universidad Mayor de San Andrés; BoliviaFil: Dutrievoz, Niels. Universidad Nacional San Antonio Abad del Cusco; PerúFil: Rowe, Penny. Washington State University. School Of Earth & Environmental Sciences; Estados UnidosFil: Wille, Jonathan. Universidad Mayor de San Andrés; BoliviaFil: Favier, Vincent. Laboratoire D´ Oceanographie Et Climat, Experimentation Et Approches Numerique ; Institut Pierre Simon la Place ; Campus Pierre Et Marie Curie ; Sorbonne University;Fil: Blanchet, Juliette. Universite Grenoble Alpes.; FranciaFil: Chyhareva, Anastasiia. Universidad de Santiago de Chile. Instituto de Estudios de Posgrado E Investigación.; ChileFil: Cordero, Raul. Universidad de Santiago de Chile. Facultad de Ciencias; ChileFil: Park, Sang Jong. Korea Polar Research Institute; Corea del SurFil: Colwell, Steve. British Antartic Survey; Reino UnidoFil: Lazzara, Matthew. University of Wisconsin; Estados UnidosFil: Carrasco, Jorge. Universidad de Magallanes; ChileFil: Gulisano, Adriana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Ministerio de Relaciones Exteriores, Comercio Interno y Culto. Dirección Nacional del Antártico. Instituto Antártico Argentino; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; ArgentinaFil: Krakovska, Svitlana. Universidad de Santiago de Chile. Facultad de Ciencias; ChileFil: Ralph, F. Martin. University of Washington; Estados UnidosFil: Pohl, Benjamin. Universidad Industrial Santander; Colombi