PECULIAR EUPHROSYNE

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Dynamical evolution of V-type photometric candidates in the outer main belt

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo preliminar do potencial de alguns asteroides

A survey we conducted, and bring expressed in this text is a preliminary study on the shape of asteroids and allowed us to understand a little more the dynamics around these bodies, in order that the images we have of asteroids are the most irregular possible. In this work, the asteroid is modeled by the method of the polyhedron, which provides a very good accuracy of the irregular shape of the body. Through study of models for non-spherical gravitational potential bodies, implementation of computational algorithms and numerical simulations a preliminary analysis was performed in relation to the shape of asteroids 4179 Toutatis, 6489 Golevka, 2063 Bacchus, 1620 Geographos and 1998 ML14, as well as regions of stability instability, we compute the coefficients of the gravitational potential. The work not only enables expansion for the case of asteroids, but also for other non-spherical bodies, contributing to the development of targeted studies the origin and evolution of the solar system, and perhaps the origin of the earth, and new technologies for modeling and mapping of non-spherical bodies. The main results were obtained by analyzing the graphics format and planning of asteroids, which confirmed how these bodies are irregular and show how distribution of non-homogeneous mass. Observe the behavior of the curves of zero velocity and equipotential curves as well as their respective surfaces. Also, compute some values of the gravitational potential and the spherical harmonic coefficients of each object. Furthermore, we find possible equilibrium points of asteroids except 4179 Toutatis, and analyze its stability

Captura gravitacional de pequenos corpos por arrasto em um gás modelado usando equações hidrodinâmicas

In this work we have developed an apparatus in order to study the capture of asteroids by planets surrounded by a gas envelope during y-by, to do this we have brought an innovation by using a hydrodynamical gas. We began such project by studying particles trajectories with a code based on the analytical gas. After being used to this model we have started a process to elaborate a code which uses the gas in a numerical way. The hydrodynamical gas is described by equations which are not solved analytically. Therefore, it was used an algorithm able to model the gas by keeping all information of the gas in cells. Thus we have made a code to read such cell`s information and then to solve all calculations. Once this process is done, the program inform us all date about the simulated trajectories

Resonance capture at arbitrary inclination

Resonance capture is studied numerically in the three-body problem for arbitrary inclinations. Massless particles are set to drift from outside the 1: 5 resonance with a Jupiter-mass planet thereby encountering the web of the planet's diverse mean motion resonances. Randomly constructed samples explore parameter space for inclinations from 0 to 180 degrees with 5 degrees increments totalling nearly 6 x 10(5) numerical simulations. 30 resonances internal and external to the planet's location are monitored. We find that retrograde resonances are unexpectedly more efficient at capture than prograde resonances and that resonance order is not necessarily a good indicator of capture efficiency at arbitrary inclination. Capture probability drops significantly at moderate sample eccentricity for initial inclinations in the range [10 degrees,110 degrees]. Orbit inversion is possible for initially circular orbits with inclinations in the range [60 degrees,130 degrees]. Capture in the 1:1 co-orbital resonance occurs with great likelihood at large retrograde inclinations. The planet's orbital eccentricity, if larger than 0.1, reduces the capture probabilities through the action of the eccentric Kozai-Lidov mechanism. A capture asymmetry appears between inner and outer resonances as prograde orbits are preferentially trapped in inner resonances. The relative capture efficiency of retrograde resonance suggests that the dynamical lifetimes of Damocloids and Centaurs on retrograde orbits must be significantly larger than those on prograde orbits implying that the recently identified asteroids in retrograde resonance, 2006 BZ8, 2008 SO218, 2009 QY6 and 1999 LE31 may be among the oldest small bodies that wander between the outer giant planets.

Stable retrograde orbits around the triple system 2001 SN263

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Celestial mechanics: from the errant stars to guidance of spacecrafts

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Regiões de estabilidade no ambiente de um sistema de asteroide triplo

This work was developed from the study by Araujo, R.A.N. et al. Stability regions around the components of the triple system 2001 SN263. (Monthly Notices Of The Royal Astronomical Society, 2012, v. 423(4), 3058-3073 p.) where it was studied the stable and unstable regions system (2001 SN263), which is a triple asteroid system, and these are celestial orbiting our sun. Being close to the Earth is characterized as NEA (Near-Earth Asteroids), asteroids and which periodically approach the Earth's orbit, given that there is great interest in the study and exploitation of these objects, it is the key can carry features that contribute to better understand the process of formation of our solar system. Study the dynamics of bodies that govern those systems proves to be greatly attractive because of the mutual gravitational perturbation of bodies and also by external disturbances. Recently, NEA 2001 SN263 was chosen as a target of Aster mission where a probe is sent for this triple system, appearing therefore the need for obtaining information for characterizing stable regions internal and external to the system, with respect to the effects of radiation pressure. First, this study demonstrated that the integrator used showed satisfactory results of the orbital evolution of bodies in accordance with previous studies and also the characterization of stable and unstable regions brought similar results to the study by Araujo et al. (2012). From these results it was possible to carry out the implementation of the radiation pressure in the system in 2001 SN263, in a region close to the central body, where the simulations were carried out, which brought as a result that the regions before being characterized as stable in unstable true for small particles size from 1 to 5 micrometers. So the next orbital region to the central body and the ... ( Complete abstract click electronic access below)

Regiões de estabilidade no ambiente de um sistema de asteroide triplo

This work was developed from the study by Araujo, R.A.N. et al. Stability regions around the components of the triple system 2001 SN263. (Monthly Notices Of The Royal Astronomical Society, 2012, v. 423(4), 3058-3073 p.) where it was studied the stable and unstable regions system (2001 SN263), which is a triple asteroid system, and these are celestial orbiting our sun. Being close to the Earth is characterized as NEA (Near-Earth Asteroids), asteroids and which periodically approach the Earth's orbit, given that there is great interest in the study and exploitation of these objects, it is the key can carry features that contribute to better understand the process of formation of our solar system. Study the dynamics of bodies that govern those systems proves to be greatly attractive because of the mutual gravitational perturbation of bodies and also by external disturbances. Recently, NEA 2001 SN263 was chosen as a target of Aster mission where a probe is sent for this triple system, appearing therefore the need for obtaining information for characterizing stable regions internal and external to the system, with respect to the effects of radiation pressure. First, this study demonstrated that the integrator used showed satisfactory results of the orbital evolution of bodies in accordance with previous studies and also the characterization of stable and unstable regions brought similar results to the study by Araujo et al. (2012). From these results it was possible to carry out the implementation of the radiation pressure in the system in 2001 SN263, in a region close to the central body, where the simulations were carried out, which brought as a result that the regions before being characterized as stable in unstable true for small particles size from 1 to 5 micrometers. So the next orbital region to the central body and the ... ( Complete abstract click electronic access below)

VVV DR1: The first data release of the Milky Way bulge and southern plane from the near-infrared ESO public survey VISTA variables in the Via Lactea

Context. The ESO public survey VISTA variables in the Via Lactea (VVV) started in 2010. VVV targets 562 sq. deg in the Galactic bulge and an adjacent plane region and is expected to run for about five years. Aims. We describe the progress of the survey observations in the first observing season, the observing strategy, and quality of the data obtained. Methods. The observations are carried out on the 4-m VISTA telescope in the ZYJHK(s) filters. In addition to the multi-band imaging the variability monitoring campaign in the K-s filter has started. Data reduction is carried out using the pipeline at the Cambridge Astronomical Survey Unit. The photometric and astrometric calibration is performed via the numerous 2MASS sources observed in each pointing. Results. The first data release contains the aperture photometry and astrometric catalogues for 348 individual pointings in the ZYJHK(s) filters taken in the 2010 observing season. The typical image quality is similar to 0 ''.9-1 ''.0. The stringent photometric and image quality requirements of the survey are satisfied in 100% of the JHK(s) images in the disk area and 90% of the JHK(s) images in the bulge area. The completeness in the Z and Y images is 84% in the disk, and 40% in the bulge. The first season catalogues contain 1.28 x 10(8) stellar sources in the bulge and 1.68 x 10(8) in the disk area detected in at least one of the photometric bands. The combined, multi-band catalogues contain more than 1.63 x 10(8) stellar sources. About 10% of these are double detections because of overlapping adjacent pointings. These overlapping multiple detections are used to characterise the quality of the data. The images in the JHK(s) bands extend typically similar to 4 mag deeper than 2MASS. The magnitude limit and photometric quality depend strongly on crowding in the inner Galactic regions. The astrometry for K-s = 15-18 mag has rms similar to 35-175 mas. Conclusions. The VVV Survey data products offer a unique dataset to map the stellar populations in the Galactic bulge and the adjacent plane and provide an exciting new tool for the study of the structure, content, and star-formation history of our Galaxy, as well as for investigations of the newly discovered star clusters, star-forming regions in the disk, high proper motion stars, asteroids, planetary nebulae, and other interesting objects.

Effects of high-energy astrophysical events on habitable planets

With the possible exception of meteor impacts, high-energy astrophysical events such as supernovae, gamma-ray bursts (GRB) and flares are usually not taken into account for biological and evolutionary studies due to their low rates of occurrence. We show that a class of these events may occur at distances and time scales in which their biological effects are non-negligible, maybe more frequent than the impacts of large asteroids. We review the effects of four transient astrophysical sources of ionizing radiation on biospheres - stellar flares, giant flares from soft gamma repeaters (SGR), supernovae and GRB. The main damaging features of them are briefly discussed and illustrated. We point out some open problems and ongoing work. Received 28 February 2012, accepted 6 July 2012, first published online 10 August 2012

Modellazione CAD di modulo abitativo per stazione spaziale

L’interesse per missioni spaziali verso la luna, il pianeta Marte o asteroidi vicini NEA (near earth asteroids) è in continuo aumento; ne sono prova i numerosi concorsi di idee innovative da applicare a possibili missioni spaziali. A partire dai profili di missione e da altri dati forniti dai gruppi di ricerca attivi nel settore, mi sono occupato di svolgere la modellazione CAD concettuale di un modulo abitabile per due astronauti e, in particolare, di pensare a livello concettuale come possano essere risolte problematiche di dispiegamento del modulo e montaggio nello spazio. E’ infatti fondamentale che la struttura ripiegata possa essere inserita all’interno di un lanciatore già definito, e che possa espandersi una volta in orbita. Ho quindi svolto il disegno del modulo abitativo sia in configurazione di lancio che in configurazione dispiegata, cercando di fornire alcune prime indicazioni riguardo alle possibili configurazioni costruttive e ad una possibile sequenza di montaggio.

Space trajectories optimization using variable-chromosome-length genetic algorithms

The problem of optimal design of a multi-gravity-assist space trajectories, with free number of deep space maneuvers (MGADSM) poses multi-modal cost functions. In the general form of the problem, the number of design variables is solution dependent. To handle global optimization problems where the number of design variables varies from one solution to another, two novel genetic-based techniques are introduced: hidden genes genetic algorithm (HGGA) and dynamic-size multiple population genetic algorithm (DSMPGA). In HGGA, a fixed length for the design variables is assigned for all solutions. Independent variables of each solution are divided into effective and ineffective (hidden) genes. Hidden genes are excluded in cost function evaluations. Full-length solutions undergo standard genetic operations. In DSMPGA, sub-populations of fixed size design spaces are randomly initialized. Standard genetic operations are carried out for a stage of generations. A new population is then created by reproduction from all members based on their relative fitness. The resulting sub-populations have different sizes from their initial sizes. The process repeats, leading to increasing the size of sub-populations of more fit solutions. Both techniques are applied to several MGADSM problems. They have the capability to determine the number of swing-bys, the planets to swing by, launch and arrival dates, and the number of deep space maneuvers as well as their locations, magnitudes, and directions in an optimal sense. The results show that solutions obtained using the developed tools match known solutions for complex case studies. The HGGA is also used to obtain the asteroids sequence and the mission structure in the global trajectory optimization competition (GTOC) problem. As an application of GA optimization to Earth orbits, the problem of visiting a set of ground sites within a constrained time frame is solved. The J2 perturbation and zonal coverage are considered to design repeated Sun-synchronous orbits. Finally, a new set of orbits, the repeated shadow track orbits (RSTO), is introduced. The orbit parameters are optimized such that the shadow of a spacecraft on the Earth visits the same locations periodically every desired number of days.

All-sky Meteor Orbit System AMOS and preliminary analysis of three unusual meteor showers

All-sky Meteor Orbit System (AMOS) is a semi-autonomous video observatory for detection of transient events on the sky, mostly the meteors. Its hardware and software development and permanent placement on several locations in Slovakia allowed the establishment of Slovak Video Meteor Network (SVMN) monitoring meteor activity above the Central Europe. The data reduction, orbital determination and additional results from AMOS cameras–the SVMN database– as well as from observational expeditions on Canary Islands and in Canada provided dynamical and physical data for better understanding of mutual connections between parent bodies of asteroids and comets and their meteoroid streams. We present preliminary results on exceptional and rare meteor streams such as September ε Perseids (SPE) originated from unknown long periodic comet on a retrograde orbit, suspected asteroidal meteor stream of April α Comae Berenicids (ACO) in the orbit of meteorites Příbram and Neuschwanstein and newly observed meteor stream Camelopardalids (CAM) originated from Jupiter family comet 209P/Linear.