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Author Casassus, S.; Christiaens, V.; Carcamo, M.; Perez, S.; Weber, P.; Ercolano, B.; van der Marel, N.; Pinte, C.; Dong, R.B.; Baruteau, C.; Cieza, L.; van Dishoeck, E.F.; Jordan, A.; Price, D.J.; Absil, O.; Arce-Tord, C.; Faramaz, V.; Flores, C.; Reggiani, M.
Title A dusty filament and turbulent CO spirals in HD 135344B-SAO 206462 Type
Year 2021 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 507 Issue 3 Pages 3789-3809
Keywords protoplanetary discs; accretion, accretion discs; planet-disc interactions
Abstract 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 HD 135344B disc revealed two rings in the thermal continuum stemming from similar to mm-sized dust. At higher frequencies the inner ring is brighter relative to the outer ring, which is also shaped as a crescent rather than a full ring. In near-IR scattered light images, the disc is modulated by a two-armed grand-design spiral originating inside the ALMA inner ring. Such structures may be induced by a massive companion evacuating the central cavity, and by a giant planet in the gap separating both rings, that channels the accretion of small dust and gas through its filamentary wakes while stopping the larger dust from crossing the gap. Here we present ALMA observations in the J = (2 – 1) CO isotopologue lines and in the adjacent continuum, with up to 12 km baselines. Angular resolutions of similar to 0 ''.03 reveal the tentative detection of a filament connecting both rings, and which coincides with a local discontinuity in the pitch angle of the IR spiral, proposed previously as the location of the protoplanet driving this spiral. Line diagnostics suggests that turbulence, or superposed velocity components, is particularly strong in the spirals. The (CO)-C-12(2-1) 3D rotation curve points at stellocentric accretion at radii within the inner dust ring, with a radial velocity of up to similar to 5 per cent +/- 0.5 per cent Keplerian, which corresponds to an excessively large accretion rate of similar to 2 x 10(-6) M circle dot yr(-1) if all of the CO layer follows the (CO)-C-12(2-1) kinematics. This suggests that only the surface layers of the disc are undergoing accretion, and that the line broadening is due to superposed laminar flows.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000708848000046 Approved
Call Number UAI @ alexi.delcanto @ Serial 1484
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Author Mulders, G.D.; Drazkowska, J.; van der Marel, N.; Ciesla, F.J.; Pascucci, I.
Title Why Do M Dwarfs Have More Transiting Planets? Type
Year 2021 Publication Astrophysical Journal Letters Abbreviated Journal Astrophys. J. Lett.
Volume 920 Issue 1 Pages L1
Keywords TERRESTRIAL PLANETS; GRADUAL ACCUMULATION; GIANT PLANETS; EMBRYOS
Abstract We propose a planet formation scenario to explain the elevated occurrence rates of transiting planets around M dwarfs compared to Sun-like stars discovered by Kepler. We use a pebble drift and accretion model to simulate the growth of planet cores inside and outside of the snow line. A smaller pebble size interior to the snow line delays the growth of super-Earths, allowing giant planet cores in the outer disk to form first. When those giant planets reach pebble isolation mass they cut off the flow of pebbles to the inner disk and prevent the formation of close-in super-Earths. We apply this model to stars with masses between 0.1 and 2 M (circle dot) and for a range of initial disk masses. We find that the masses of hot super-Earths and of cold giant planets are anticorrelated. The fraction of our simulations that form hot super-Earths is higher around lower-mass stars and matches the exoplanet occurrence rates from Kepler. The fraction of simulations forming cold giant planets is consistent with the stellar mass dependence from radial-velocity surveys. A key testable prediction of the pebble accretion hypothesis is that the occurrence rates of super-Earths should decrease again for M dwarfs near the substellar boundary like Trappist-1.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-8205 ISBN Medium
Area Expedition Conference
Notes WOS:000703719200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1478
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Author van der Marel, N.; Mulders, G.D.
Title A Stellar Mass Dependence of Structured Disks: A Possible Link with Exoplanet Demographics Type
Year 2021 Publication Astronomical Journal Abbreviated Journal Astron. J.
Volume 162 Issue 1 Pages 28
Keywords GIANT PLANET OCCURRENCE; X-SHOOTER SPECTROSCOPY; MAIN-SEQUENCE STARS; CIRCLE-DOT STARS; ALMA SURVEY; PROTOPLANETARY DISKS; CIRCUMSTELLAR DISKS; TRANSITION DISKS; MILLIMETER CONTINUUM; CLASS-II
Abstract Gaps in protoplanetary disks have long been hailed as signposts of planet formation. However, a direct link between exoplanets and disks remains hard to identify. We present a large sample study of ALMA disk surveys of nearby star-forming regions to disentangle this connection. All disks are classified as either structured (transition, ring, extended) or nonstructured (compact) disks. Although low-resolution observations may not identify large-scale substructure, we assume that an extended disk must contain substructure from a dust evolution argument. A comparison across ages reveals that structured disks retain high dust masses up to at least 10 Myr, whereas the dust mass of compact, nonstructured disks decreases over time. This can be understood if the dust mass evolves primarily by radial drift, unless drift is prevented by pressure bumps. We identify a stellar mass dependence of the fraction of structured disks. We propose a scenario linking this dependence with that of giant exoplanet occurrence rates. We show that there are enough exoplanets to account for the observed disk structures if transitional disks are created by exoplanets more massive than Jupiter and ring disks by exoplanets more massive than Neptune, under the assumption that most of those planets eventually migrate inwards. On the other hand, the known anticorrelation between transiting super-Earths and stellar mass implies those planets must form in the disks without observed structure, consistent with formation through pebble accretion in drift-dominated disks. These findings support an evolutionary scenario where the early formation of giant planets determines the disk's dust evolution and its observational appearance.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-6256 ISBN Medium
Area Expedition Conference
Notes WOS:000664728300001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1431
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Author van der Marel, N.; Bosman, A.D.; Krijt, S.; Mulders, G.D.; Bergner, J.B.
Title If you like C/O variations, you should have put a ring on it Type
Year 2021 Publication Astronomy & Astrophysics Abbreviated Journal Astron. Astrophys.
Volume 653 Issue Pages L9
Keywords astrochemistry; molecular data; planets and satellites; formation; protoplanetary disks
Abstract Context. The C/O ratio as traced with C2H emission in protoplanetary disks is fundamental for constraining the formation mechanisms of exoplanets and for our understanding of volatile depletion in disks, but current C2H observations show an apparent bimodal distribution that is not well understood, indicating that the C/O distribution is not described by a simple radial dependence. Aims. The transport of icy pebbles has been suggested to alter the local elemental abundances in protoplanetary disks through settling, drift, and trapping in pressure bumps, resulting in a depletion of volatiles in the surface layer and an increase in the elemental C/O. Methods. We combine all disks with spatially resolved ALMA C2H observations with high-resolution continuum images and constraints on the CO snow line to determine if the C2H emission is indeed related to the location of the icy pebbles. Results. We report a possible correlation between the presence of a significant CO-ice dust reservoir and high C2H emission, which is only found in disks with dust rings outside the CO snow line. In contrast, compact dust disks (without pressure bumps) and warm transition disks (with their dust ring inside the CO snow line) are not detected in C2H, suggesting that such disks may have never contained a significant CO ice reservoir. Conclusions. This correlation provides evidence for the regulation of the C/O profile by the complex interplay of CO snow line and pressure bump locations in the disk. These results demonstrate the importance of including dust transport in chemical disk models for a proper interpretation of exoplanet atmospheric compositions and a better understanding of volatile depletion in disks, in particular the use of CO isotopologs to determine gas surface densities.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-6361 ISBN Medium
Area Expedition Conference
Notes WOS:000698590500002 Approved
Call Number UAI @ alexi.delcanto @ Serial 1482
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