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Author Allen, N.H.; Espinoza, N.; Jordan, A.; Lopez-Morales, M.; Apai, D.; Rackham, B.V.; Kirk, J.; Osip, D.J.; Weaver, I.C.; McGruder, C.; Ceballos, K.O.; Reggiani, H.; Brahm, R.; Rodler, F.; Lewis, N.K.; Fraine, J.
Title ACCESS: Tentative Detection of H2O in the Ground-based Optical Transmission Spectrum of the Low-density Hot Saturn HATS-5b Type
Year 2022 Publication Astronomical Journal Abbreviated Journal Astron. J.
Volume 164 Issue 4 Pages 153
Keywords BAYESIAN-INFERENCE; EXOPLANET; SKY; ATMOSPHERES; EFFICIENT; TOOL; CHEMISTRY; ASTROPY
Abstract We present a precise ground-based optical transmission spectrum of the hot Saturn HATS-5b (T (eq) = 1025 K), obtained as part of the ACCESS survey with the IMACS multi-object spectrograph mounted on the Magellan Baade Telescope. Our spectra cover the 0.5-0.9 mu m region and are the product of five individual transits observed between 2014 and 2018. We introduce the usage of additional second-order light in our analyses, which allows us to extract an “extra” transit light curve, improving the overall precision of our combined transit spectrum. We find that the favored atmospheric model for this transmission spectrum is a solar-metallicity atmosphere with subsolar C/O, whose features are dominated by H2O and with a depleted abundance of Na and K. If confirmed, this would point to a “clear” atmosphere at the pressure levels probed by transmission spectroscopy for HATS-5b. Our best-fit atmospheric model predicts a rich near-IR spectrum, which makes this exoplanet an excellent target for future follow-up observations with the James Webb Space Telescope, both to confirm this H2O detection and to superbly constrain the atmosphere's parameters.
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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:000856537200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1650
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Author Gaspers, S.; Liedloff, M.; Stein, M.; Suchan, K.
Title Complexity of splits reconstruction for low-degree trees Type
Year 2015 Publication Discrete Applied Mathematics Abbreviated Journal Discret Appl. Math.
Volume 180 Issue Pages 89-100
Keywords Reconstruction of trees; Computational complexity; Computational chemistry
Abstract Given a vertex-weighted tree T, the split of an edge em T is the minimum over the weights of the two trees obtained by removing e from T, where the weight of a tree is the sum of weights of its vertices. Given a set of weighted vertices V and a multiset of integers s, we consider the problem of constructing a tree on V whose splits correspond to s. The problem is known to be NP-complete, even when all vertices have unit weight and the maximum vertex degree of T is required to be at most 4. We show that the problem is strongly NP-complete when T is required to be a path, the problem is NP-complete when all vertices have unit weight and the maximum degree of T is required to be at most 3, and it remains NP-complete when all vertices have unit weight and T is required to be a caterpillar with unbounded hair length and maximum degree at most 3. We also design polynomial time algorithms for the variant where T is required to be a path and the number of distinct vertex weights is constant, and the variant where all vertices have unit weight and T has a constant number of leaves. The latter algorithm is not only polynomial when the number of leaves, k, is a constant, but also is a fixed-parameter algorithm for parameter k. Finally, we shortly discuss the problem when the vertex weights are not given but can be freely chosen by an algorithm. The considered problem is related to building libraries of chemical compounds used for drug design and discovery. In these inverse problems, the goal is to generate chemical compounds having desired structural properties, as there is a strong relation between structural invariants of the particles, such as the Wiener index and, less directly, the problem under consideration here, and physico-chemical properties of the substance. (C) 2014 Elsevier B.V. All rights reserved.
Address [Gaspers, Serge] Univ New S Wales, Sch Comp Sci & Engn, Sydney, NSW 2052, Australia, Email: sergeg@cse.unsw.edu.au;
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0166-218x ISBN Medium
Area Expedition Conference
Notes WOS:000346545500009 Approved
Call Number UAI @ eduardo.moreno @ Serial 433
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Author Kirk, J.; Rackham, B.V.; MacDonald, R.J.; Lopez-Morales, M.; Espinoza, N.; Lendl, M.; Wilson, J.; D.J.; Wheatley, P.J.; Skillen, I.; Apai, D.; Bixel, A.; Gibson, N.P.; Jordan, A.; Lewis, N.K.; Louden, T.; McGruder, C.D.; Nikolov, N.; Rodler, F.; Weaver, I.C.
Title ACCESS and LRG-BEASTS: A Precise New Optical Transmission Spectrum of the Ultrahot Jupiter WASP-103b Type
Year 2021 Publication Astronomical Journal Abbreviated Journal Astron. J.
Volume 162 Issue 1 Pages 34
Keywords GAS-GIANT EXOPLANET; HOT JUPITERS; ATMOSPHERES; TRANSIT; PLANET; EFFICIENT; SPECTROSCOPY; RETRIEVAL; CHEMISTRY; EXPLAIN
Abstract We present a new ground-based optical transmission spectrum of the ultrahot Jupiter WASP-103b (Teq=2484
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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:000667942900001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1434
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Author Pina, S.; Candia-Onfray, C.; Hassan, N.; Jara-Ulloa, P.; Contreras, D.; Salazar, R.
Title Glassy Carbon Electrode Modified with C/Au Nanostructured Materials for Simultaneous Determination of Hydroquinone and Catechol in Water Matrices Type
Year 2021 Publication Chemosensors Abbreviated Journal Chemosensors
Volume 9 Issue 5 Pages 88
Keywords ENDOCRINE DISRUPTING COMPOUNDS; IONIC LIQUID COMPOSITE; GOLD NANOPARTICLES; ELECTROCHEMICAL SENSOR; ELECTROCATALYTIC OXIDATION; VOLTAMMETRIC DETERMINATION; ANALYTICAL-CHEMISTRY; PASTE ELECTRODE; NANOTUBES; RESORCINOL
Abstract The simultaneous determination of hydroquinone and catechol was conducted in aqueous and real samples by means of differential pulse voltammetry (DPV) using a glassy carbon electrode modified with Gold Nanoparticles (AuNP) and functionalized multiwalled carbon nanotubes by drop coating. A good response was obtained in the simultaneous determination of both isomers through standard addition to samples prepared with analytical grade water and multivariate calibration by partial least squares (PLS) in winery wastewater fortified with HQ and CT from 4.0 to 150.00 mu M. A sensitivity of 0.154 mu A mu M-1 and 0.107 mu A mu M-1, and detection limits of 4.3 and 3.9 mu M were found for hydroquinone and catechol, respectively. We verified the reliability of the developed method by simultaneously screening analytes in spiked tap water and industrial wastewater, achieving recoveries over 80%. In addition, this paper demonstrates the applicability of chemometric tools for the simultaneous quantification of both isomers in real matrices, obtaining prediction errors of lower than 10% in fortified wastewater.
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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 2227-9040 ISBN Medium
Area Expedition Conference
Notes WOS:000653570100001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1389
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Author Torres, R.; Manriquez, P.H.; Duarte, C.; Navarro, J.M.; Lagos, N.A.; Vargas, C.A.; Lardies, M.A.
Title Evaluation of a semi-automatic system for long-term seawater carbonate chemistry manipulation Type
Year 2013 Publication Revista Chilena De Historia Natural Abbreviated Journal Rev. Chil. Hist. Nat.
Volume 86 Issue 4 Pages 443-451
Keywords carbonate chemistry manipulation; ocean acidification
Abstract The assessment of the effects of Ocean Acidification (OA) on marine life has received increasing attention in recent marine research. On a mesocosmic scale, the CO2 levels in seawater can be manipulated to evaluate experimentally the consequences of OA on marine organisms (vertebrates and invertebrates). An ideal manipulation of carbonate chemistry should mimic exactly the changes to carbonate chemistry, which will occur in years to come. Although some methods have been described in the literature, here we describe in detail a simple, robust and inexpensive system to produce CO2-enriched seawater by bubbling the seawater with air-CO2 mixtures. The system uses mass flow controllers (MFC) to blend atmospheric air with pure CO2 to produce two pCO(2) levels. The air-CO2 mixtures are delivered continuously to seawater equilibration reservoirs, and simultaneously to an infrared CO2 analyser to verify CO2 levels in the air-CO2 mixture delivered to the equilibration tanks. We monitored both pH and total alkalinity in the equilibration reservoirs over a period of one year in order to document the long-term performance of this system for simulating the future carbonate chemistry of seawater in a coastal laboratory. System performance was sufficient to maintain three contrasting (e.g., 397, 709 and 1032 matm) and relatively constant (the coefficient of variability was 11 %, 9 % and 9 % respectively) seawater pCO(2) during a year-long monitoring.
Address [Torres, Rodrigo] CIEP, Coyhaique, Chile, Email: rtorres@ciep.cl
Corporate Author Thesis
Publisher Soc Biolgia Chile Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0716-078x ISBN Medium
Area Expedition Conference
Notes WOS:000332750700006 Approved
Call Number UAI @ eduardo.moreno @ Serial 359
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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.
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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 0004-6361 ISBN Medium
Area Expedition Conference
Notes WOS:000698590500002 Approved
Call Number UAI @ alexi.delcanto @ Serial 1482
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