Glory revealed in disk-integrated photometry of Venus

Context. Reflected light from a spatially unresolved planet yields unique insight into the overall optical properties of the planet cover. Glories are optical phenomena caused by light that is backscattered within spherical droplets following a narrow distribution of sizes; they are well known on Earth as localised features above liquid clouds. Aims. Here we report the first evidence for a glory in the disk-integrated photometry of Venus and, in turn, of any planet. Methods. We used previously published phase curves of the planet that were reproduced over the full range of phase angles with model predictions based on a realistic description of the Venus atmosphere. We assumed that the optical properties of the planet as a whole can be described by a uniform and stable cloud cover, an assumption that agrees well with observational evidence. Results. We specifically show that the measured phase curves mimic the scattering properties of the Venus upper-cloud micron-sized aerosols, also at the small phase angles at which the glory occurs, and that the glory contrast is consistent with what is expected after multiple scattering of photons. In the optical, the planet appears to be brighter at phase angles of 11-13 deg than at full illumination; it undergoes a maximum dimming of up to 10 percent at phases in between. Conclusions. Glories might potentially indicate spherical droplets and, thus, extant liquid clouds in the atmospheres of exoplanets. A prospective detection will require exquisite photometry at the small planet-star separations of the glory phase angles.Comment: In press. Astronomy & Astrophysics. Letter to the Editor; 201

Multilayer hazes over Saturn’s hexagon from Cassini ISS limb images

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Temporal and spatial variations of the absolute reflectivity of Jupiter and Saturn from 0.38 to 1.7 μ\mum with PlanetCam-UPV/EHU

We provide measurements of the absolute reflectivity of Jupiter and Saturn along their central meridians in filters covering a wide range of visible and near-infrared wavelengths (from 0.38 to 1.7 $\mu$m) that are not often presented in the literature. We also give measurements of the geometric albedo of both planets and discuss the limb-darkening behavior and temporal variability of their reflectivity values for a period of four years (2012-2016). This work is based on observations with the PlanetCam-UPV/EHU instrument at the 1.23 m and 2.2 m telescopes in Calar Alto Observatory (Spain). The instrument simultaneously observes in two channels: visible (VIS; 0.38-1.0 $\mu$m) and short-wave infrared (SWIR; 1.0--1.7 $\mu$m). We obtained high-resolution observations via the lucky-imaging method. We show that our calibration is consistent with previous independent determinations of reflectivity values of these planets and, for future reference, provide new data extended in the wavelength range and in the time. Our results have an uncertainty in absolute calibration of 10--20\%. We show that under the hypothesis of constant geometric albedo, we are able to detect absolute reflectivity changes related to planetary temporal evolution of about 5-10\%.Comment: 13 pages, 18 figures, (in press

Magneto--thermal evolution of neutron stars

We study the mutual influence of thermal and magnetic evolution in a neutron star's crust in axial symmetry. Taking into account realistic microphysical inputs, we find the heat released by Joule effect consistent with the circulation of currents in the crust, and we incorporate its effects in 2D cooling calculations. We solve the induction equation numerically using a hybrid method (spectral in angles, but a finite--differences scheme in the radial direction), coupled to the thermal diffusion equation. We present the first long term 2D simulations of the coupled magneto-thermal evolution of neutron stars. This substantially improves previous works in which a very crude approximation in at least one of the parts (thermal or magnetic diffusion) has been adopted. Our results show that the feedback between Joule heating and magnetic diffusion is strong, resulting in a faster dissipation of the stronger fields during the first million years of a NS's life. As a consequence, all neutron stars born with fields larger than a critical value (about 5 10^13 G) reach similar field strengths (approximately 2-3 10^{13} G) at late times. Irrespectively of the initial magnetic field strength, after $10^6$ years the temperature becomes so low that the magnetic diffusion timescale becomes longer than the typical ages of radio--pulsars, thus resulting in apparently no dissipation of the field in old NS. We also confirm the strong correlation between the magnetic field and the surface temperature of relatively young NSs discussed in preliminary works. The effective temperature of models with strong internal toroidal components are systematically higher than those of models with purely poloidal fields, due to the additional energy reservoir stored in the toroidal field that is gradually released as the field dissipates.Comment: 10 pages, 5 figures, accepted for publication in A&

Reanalyzing Jupiter ISO/SWS Data through a More Recent Atmospheric Model

The study of isotopic ratios in planetary atmospheres gives an insight into the formation history and evolution of these objects. The more we can constrain these ratios, the better we can understand the history and future of our solar system. To help in this endeavour, we used Infrared Space Observatory Short Wavelength Spectrometer (ISO/SWS) Jupiter observations in the 793–1500 cm−1 region together with the Nonlinear Optimal Estimator for MultivariatE Spectral analySIS (NEMESIS) radiative transfer suite to retrieve the temperature–pressure profile and the chemical abundances for various chemical species. We also used the 1500–2499 cm−1 region to determine the cloud and aerosol structure of the upper troposphere. We obtained a best-fit simulated spectrum with 2/=0.47 for the 793–1500 cm−1 region and 2/=0.71 for the 1500–2499 cm−1 region. From the retrieved methane abundances, we obtained, within a 1 uncertainty, a 12C/13C ratio of 84 ± 27 and a D/H ratio of (3.5 ± 0.6) × 10−5, and these ratios are consistent with other published results from the literature.This research was funded by the Portuguese Fundação Para a Ciência e Tecnologia through the research grants UIDB/04434/2020 and UIDP/04434/2020 as well as a fellowship grants 2021.04584.BD and 2022.09859.BD

Validación por la Comunidad Docente de una Metodología de Aprendizaje Activo para Cursos de Programación

Actas de: III Jornadas de Innovación Educativa en Ingeniería Telemática (JIE). Granada, 28-30 Octubre 2013.En este artículo se presenta y evalúa una metodología para cursos de programación, basada en el aprendizaje activo y el aprendizaje basado en proyectos. Esta metodología se centra en el trabajo continuo, día a día, del alumno. Por un lado, ofrece pautas para que los alumnos organicen su tiempo, promoviendo el autoaprendizaje y el trabajo individual. Por otro, durante el proyecto los alumnos desarrollan sus capacidades de trabajo en equipo, fomentando el desarrollo de competencias transversales como el aprendizaje colaborativo. La metodología descrita se ha aplicado durante varios cursos en una asignatura de programación en C de segundo curso de los cuatro grados de Ingeniería de Telecomunicaciones. Para poder evaluar, ajustar y mejorar el proceso de enseñanzaaprendizaje propuesto, se utilizan mecanismos de realimentación y seguimiento del alumnado y del profesorado. En este artículo, la implantación de la metodología es evaluada por 40 profesores de distintas universidades españolas que imparten asignaturas en cursos de ingeniería, con objeto de validar su aplicabilidad en otros contextos.Este trabajo ha sido financiado parcialmente por el proyecto nacional del Ministerio de Economía y Competitividad, “Espacios Educativos Especulares” - EEE (TIN2011-28308-C03-01), por el proyecto regional de la Comunidad de Madrid, “eMadrid” (S2009/TIC-1650) y por el programa de estancias postdoctorales Alianza 4 Universidades.Publicad

Low temperature catalytic adsorption of NO over activated carbon honeycomb (ACH) monoliths

ABSTRACT: An activated carbon honeycomb (ACH) monolith was developed for the adsorption of NO at 30ºC. For ACH monoliths preparation carboxymethylcellulose (CMC) and coal tar pitch were used as binder and co-binder, respectively. The effects of the addition of O2 and the presence of copper as catalyst were studied. For the Cu-impregnated activated carbon monolith samples, the presence of O2 favored NO adsorption by increasing the breakthrough time and the adsorption capacity.RESUMEN: Se desarrolló un monolito tipo celular de carbón activado (ACH) para la adsorción de NO a 30ºC. Para la preparación de los monolitos celulares se usó como aglomerante la carboximetilcelulosa (CMC) y como coaglomerante brea de alquitranes de carbón (BAC). Se estudiaron los efectos de la adición de O2 y la presencia de cobre como catalizador. Para las muestras de monolito de carbón activado impregnado con Cu, la presencia de O2 favoreció la adsorción de NO incrementando el tiempo del punto de quiebre (breakthrough) y la capacidad de adsorción

A Review of Advances in the Identification and Characterization of Groundwater Dependent Ecosystems Using Geospatial Technologies

Groundwater Dependent Ecosystem (GDE) protection is increasingly being recognized as essential for the sustainable management and allocation of water resources. GDE services are crucial for human well-being and for a variety of flora and fauna. However, the conservation of GDEs is only possible if knowledge about their location and extent is available. Several studies have focused on the identification of GDEs at specific locations using ground-based measurements. However, recent progress in remote sensing technologies and their integration with Geographic Information Systems (GIS) has provided alternative ways to map GDEs at a much larger spatial extent. This paper presents a review of the geospatial methods that have been used to map and delineate GDEs at spatial different extents. Additionally, a summary of the satellite sensors useful for identification of GDEs and the integration of remote sensing data with ground-based measurements in the process of mapping GDEs is presented

A complex storm system in Saturn’s north polar atmosphere in 2018

Producción CientíficaSaturn’s convective storms usually fall in two categories. One consists of mid-sized storms ∼2,000 km wide, appearing as irregular bright cloud systems that evolve rapidly, on scales of a few days. The other includes the Great White Spots, planetary-scale giant storms ten times larger than the mid-sized ones, which disturb a full latitude band, enduring several months, and have been observed only seven times since 1876. Here we report a new intermediate type, observed in 2018 in the north polar region. Four large storms with east–west lengths ∼4,000–8,000 km (the first one lasting longer than 200 days) formed sequentially in close latitudes, experiencing mutual encounters and leading to zonal disturbances affecting a full latitude band ∼8,000 km wide, during at least eight months. Dynamical simulations indicate that each storm required energies around ten times larger than mid-sized storms but ∼100 times smaller than those necessary for a Great White Spot. This event occurred at about the same latitude and season as the Great White Spot in 1960, in close correspondence with the cycle of approximately 60 years hypothesized for equatorial Great White Spots.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AYA2015-65041-P)Gobierno Vasco (project IT-366-19