From stellar nebula to planetesimals

Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in part the composition of future planets. The present works aims at determining the chemical composition of icy planetesimals, believed to be similar to present day comets, formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data on chemical composition for models of planetesimals and comets, and models of planet formation and evolution. We have developed a model that calculates the composition of ices formed during the cooling of the stellar nebula. Coupled with a model of refractory element formation, it allows us to determine the chemical composition and mass ratio of ices to rocks in icy planetesimals throughout in the protoplanetary disc. We provide relationships for ice line positions (for different volatile species) in the disc, and chemical compositions and mass ratios of ice relative to rock for icy planetesimals in stellar systems of solar chemical composition. From an initial homogeneous composition of the nebula, a wide variety of chemical compositions of planetesimals were produced as a function of the mass of the disc and distance to the star. Ices incorporated in planetesimals are mainly composed of H2O, CO, CO2, CH3OH, and NH3. The ice/rock mass ratio is equal to 1+-0.5 in icy planetesimals following assumptions. This last value is in good agreement with observations of solar system comets, but remains lower than usual assumptions made in planet formation models, taking this ratio to be of 2-3

From stellar nebula to planets: the refractory components

We computed the abundance of refractory elements in planetary bodies formed in stellar systems with solar chemical composition by combining models for chemical composition and planet formation. We also consider the formation of refractory organic compounds, which have been ignored in previous studies on this topic. We used the commercial software package HSC Chemistry in order to compute the condensation sequence and chemical composition of refractory minerals incorporated into planets. The problem of refractory organic material is approached with two distinct model calculations: the first considers that the fraction of atoms used in the formation of organic compounds is removed from the system (i.e. organic compounds are formed in the gas phase and are nonreactive); and the second assumes that organic compounds are formed by the reaction between different compounds that had previously condensed from the gas phase. Results show that refractory material represents more than 50 wt % of the mass of solids accreted by the simulated planets, with up to 30 wt % of the total mass composed of refractory organic compounds. Carbide and silicate abundances are consistent with C/O and Mg/Si elemental ratios of 0.5 and 1.02 for the Sun. Less than 1 wt % of carbides; pyroxene and olivine in similar quantities are formed. The model predicts planets that are similar in composition to those of the Solar system. It also shows that, starting from a common initial nebula composition, a wide variety of chemically different planets can form, which means that the differences in planetary compositions are due to differences in the planetary formation process. We show that a model in which refractory organic material is absent from the system is more compatible with observations. The use of a planet formation model is essential to form a wide diversity of planets in a consistent way.Comment: 18 pages, 29 figures. Accepted for publication in A&

Proyecto de Parque público San Pascual en la urbanización "Marxadella" en Torrent, Valencia

[ES] El Parque Público San Pascual se localizará en localidad de Torrent (Valencia, ESPAÑA), y contará con una extensión aproximada de 1 hectárea. Se ubicará entre las calles: Carlet y Alzira con unas coordenadas UTM de la parcela de: 30 S 717462 436730. El parque contará con distintos espacios: zona destinada a juegos infantiles; área cubierta de césped, zona de vegetación mediterránea localizadas en isletas de tierra; zona de bosquete mediterráneo. Presentará un diseño natural inspirado en el jardín mediterráneo, con vegetación resistente a la sequía y a cambios de temperatura, con toques minimalistas, intentando evitar los caminos muy rectos y las distribuciones proporcionales y artificiales. Se emplearán árboles de hoja caduca y perenne para aportar sombra en los meses cálidos, pero dejar para la luz en los fríos, además de contar con distintas alturas de vegetación para otorgar dinamismo al paisaje. Se pretende que los costes de instalación y mantenimiento sean lo más bajo posible. Está pensado para el uso de todo tipo de colectivos sin hacer distinciones de edad.[EN] The San Pascual Public Park will be located in the town of Torrent (Valencia, SPAIN), and will have an approximate area of 1 hectare. It will be located between the streets: Carlet and Alzira with UTM plot coordinates of: 30 S 717462 436730. The park will have different spaces: area for children's games; grass covered area, Mediterranean vegetation zone located in ground islets; Mediterranean forest area. It will present a natural design inspired by the Mediterranean garden, with vegetation resistant to drought and temperature changes, with minimalist touches, trying to avoid very straight roads and proportional and artificial distributions. Deciduous and perennial trees will be used to provide shade in the warm months, but leave for light in the cold, in addition to having different heights of vegetation to give dynamism to the landscape. It is intended that the installation and maintenance costs are as low as possible. It is designed for the use of all types of groups without making age distinctions.Cabral Mosquera, FN. (2018). Proyecto de Parque público San Pascual en la urbanización "Marxadella" en Torrent, Valencia. http://hdl.handle.net/10251/106519TFG

Aplicación de Sistemas Dinámicos a las Relaciones Laborales

En este trabajo se muestra la posibilidad de aplicar la teoría de sistemas dinámicos para la descripción de las relaciones laborales, como así también mencionar trabajos existentes que modelizan matemáticamente la conducta humana. A través de ecuaciones diferenciales se representan diferentes tipos de relaciones laborales.Sociedad Argentina de Informática e Investigación Operativ

JWST/NIRSpec Prospects on Transneptunian Objects

The transneptunian region has proven to be a valuable probe to test models of the formation and evolution of the solar system. To further advance our current knowledge of these early stages requires an increased knowledge of the physical properties of Transneptunian Objects (TNOs). Colors and albedos have been the best way so far to classify and study the surface properties of a large number TNOs. However, they only provide a limited fraction of the compositional information, required for understanding the physical and chemical processes to which these objects have been exposed since their formation. This can be better achieved by near-infrared (NIR) spectroscopy, since water ice, hydrocarbons, and nitrile compounds display diagnostic absorption bands in this wavelength range. Visible and NIR spectra taken from ground-based facilities have been observed for ~80 objects so far, covering the full range of spectral types: from neutral to extremely red with respect to the Sun, featureless to volatile-bearing and volatile-dominated (Barkume et al., 2008; Guilbert et al., 2009; Barucci et al., 2011; Brown, 2012). The largest TNOs are bright and thus allow for detailed and reliable spectroscopy: they exhibit complex surface compositions, including water ice, methane, ammonia, and nitrogen. Smaller objects are more difficult to observe even from the largest telescopes in the world. In order to further constrain the inventory of volatiles and organics in the solar system, and understand the physical and chemical evolution of these bodies, high-quality NIR spectra of a larger sample of TNOs need to be observed. JWST/NIRSpec is expected to provide a substantial improvement in this regard, by increasing both the quality of observed spectra and the number of observed objects. In this paper, we review the current knowledge of TNO properties and provide diagnostics for using NIRSpec to constrain TNO surface compositions

OSSOS. VII. 800+Trans-Neptunian Objects-The Complete Data Release

The Outer Solar System Origins Survey (OSSOS), a wide-field imaging program in 2013-2017 with the Canada-France-Hawaii Telescope, surveyed 155 deg(2) of sky to depths of m(r) = 24.1-25.2. We present 838 outer solar system discoveries that are entirely free of ephemeris bias. This increases the inventory of trans-Neptunian objects (TNOs) with accurately known orbits by nearly 50%. Each minor planet has 20-60 Gaia/Pan-STARRS-calibrated astrometric measurements made over 2-5 oppositions, which allows accurate classification of their orbits within the trans-Neptunian dynamical populations. The populations orbiting in mean-motion resonance with Neptune are key to understanding Neptune's early migration. Our 313 resonant TNOs, including 132 plutinos, triple the available characterized sample and include new occupancy of distant resonances out to semimajor axis a similar to 130 au. OSSOS doubles the known population of the nonresonant Kuiper Belt, providing 436 TNOs in this region, all with exceptionally high-quality orbits of a uncertainty sigma(a)Peer reviewe

Models of planetary population synthesis with magnetic cavity and stellar tides.

Pour cette thèse, nous avons été intéressé par les effets de la cavité magnétique et les effets de marées stellaires sur nos modèles de populations de synthèses planétaires. La cavité magnétique a été proposé comme un mécanisme important de la formation planétaire, en cela qu'elle peut stopper la migration radiale de la planète vers l'étoile (Lin et al. 1995). Dans ce travail on a modifié l'équation de diffusion pour l'évolution radiale de la densité de surface du disque de gas (1D), afin de tenir compte de l'effet du couple magnétique sur le disque (Armitage et al. 1999). D'autre part les effets de marées ont été inclus par un modèle analytique (Benitez-Llambay et al. 2011). Pour ce travail, on a utilisé le modèle de formation planétaire de Bern (Mordasini et al 2009a), auquel nous avons inclus ces deux effets. Enfin, nous avons comparé la distribution orbitale synthétique à la distribution orbitale observée par Kepler (Howard et al. 2012).Finalement, un dernier chapitre traite un sujet différent du reste de la thèse. Nous avons testé l'accrétion de pebbles (ou "pebble mechanism") dans le modèle de formation de Bern. Ce chapitre, est en fait un premier pas vers un modèle plus complet. Cependant, nous avons montré que l'implémentation numérique fonctionne bien.In this thesis, we have been interested on the effects of the magnetic cavity and the stellar tides in synthetic planet population. The magnetic cavity is thought be important at the formation phase since it can truncates the gaseous disk and potentially stops the inward migration of planets (Lin et al. 1995). In this work we modified the standard radial viscous equation in order to take into account the effect of the magnetic torque on the gaseous disk (Armitage et al. 1999). Moreover, the stellar tides have been included in an analytical way as in (Bénitez-Llambay et al. 2011). For this work, we used the planetary model of Bern (Mordasini et al. 2012) at which we included both effects. The end of the thesis compare the synthetic orbital distribution with the orbital distribution observed by Kepler (Howard et al. 2012).Finally, a last chapter treats a topic different than the rest of the thesis. We tested the so called pebble mechanism (Ormel&Klahr2010) in the planetary formation model of Bern. So far, this chapter is a first step to a more complete model. However, we show that the numerical implementation is working well

Diseño de matriz por deformación progresiva para la fabricación de piezas de aluminio para dispositivos electromecánicos

[ES] En el presente proyecto se detalla el proceso de diseño y cálculo de una matriz progresiva para la fabricación en serie de una pieza de aluminio para el sector electromecánico. Debido a que el número demandado de piezas a lo largo del año supera las 100.00 unidades se procederá a trabajar con una matriz progresiva, de no ser el caso se hubiesen valorado otras opciones más sencillas como pudiera ser el mecanizado. En primer lugar, se analizarán los planos dados y se generará un modelo 3D de la figura para emplearla en el proceso de diseño de la banda y posteriormente del posicionamiento de los elementos de la matriz. Una vez conseguido el diseño de la banda y las herramientas de trabajo se procederá a conformar los elementos de la matriz y a dimensionarla adecuadamente, junto con una correcta elección y explicación de materiales a emplear. Finalmente se calcularán las fuerzas necesarias para conformar todas las operaciones de punzonado, doblado y troquelado, y se describirán los medios de alimentación empleados para hacer avanzar a la banda a través de la matriz. Para el modelado 3D de la figura, obtención de planos, banda, posicionamiento de herramientas y diseño integral de la matriz se optó por usar el software NX de la casa Siemens gracias a su potente módulo de diseño de troqueles progresivos.[EN] This project details the design and calculation process of a progressive die for the serious manufacture of an aluminum part for the electromechanical sector. Since the number of pieces demanded throughout the year exceeds 100.00 units, we will proceed to work with a progressive matrix, if this were not the case, other simpler options such as machining would have been evaluated. First, the given planes will be analyzed and a 3D model of the figure will be generated to be used in the web design process and later in the positioning of the matrix elements. Once the design of the band and the work tools has been achieved, the elements of the die will be formed and it will be sized appropriately, together with a correct choice and explanation of the materials to be used. Finally, the forces necessary to shape all the punching and bending operations will be calculated, and the feeding types used to advance the strip through the die will be described. For the 3D modeling of the figure, obtaining drawings, strip, positioning of tools and integral design of the die, it was decided to use the NX software from Siemens thanks to its powerful progressive die design module.Cabral Mosquera, FN. (2021). Diseño de matriz por deformación progresiva para la fabricación de piezas de aluminio para dispositivos electromecánicos. Universitat Politècnica de València. http://hdl.handle.net/10251/179382TFG

How does the origin of stars in the Milky Way affects the composition of planet building blocks?

Our Galaxy is composed of different stellar populations which are characterized by different chemical abundances. They are thought to imprint the composition of small bodies formed together with planets : planet building blocks (PBB), asteroids and interstellar objects.We investigated the expected PBB composition in different Galactic regions using the ground-based spectroscopic surveys GALAH and APOGEE ; and the stoichiometric condensation model from Bitsch & Battistini (2020). This study has revealed the potential link between the PBB composition and the stellar populations across the Galaxy (Cabral et al, submitted). Interestingly, the PBB compositions determined from large observational surveys reveal common trends determined previously with synthetic models. We confirm the PBB composition valley separating the thin disk stars from the thick disk stars (i.e. a bimodal distribution of compositions) already highlighted in our previous study (Cabral et al. 2019) using the Besançon stellar population synthesis model of the Milky Way.Moreover, we find that metal-poor stars both in the thin and thick disks should host water-rich PBB. Given the importance of water abundance in planet formation simulations (Morbidelli et al. 2015, Ros et al. 2013, 2019), we discuss in a galactic context the potential impact for the early phases of planet formation.Overall we find that the chemical abundances of host stars should impact the composition of exoplanets, as well as small body populations found around these stars. Our results imply that thick disk stars (which are rather alpha-rich, metal-poor stars) are suitable hosts for ice-rich small bodies (cf. Figure). Whether thick disk stars are suitable for water worlds or/and hycean planets (Madhusudhan et al. 2021) remains matter of debate