In our Bayesian and Statistical Analysis investigation of the open cluster NGC 6416, we utilized Gaia EDR3 astrometry data and ensemble-based unsupervised machine learning techniques to identify 406 cluster members. Using the MESA Isochrones and Stellar Tracks (MIST) with Gaia EDR3 data, we determined the following parameters for NGC 6416: a distance of approximately 1021pc, an age of about $12.58\pm 0.1$ Myr, a metallicity (z) of roughly $0.032\pm0.0015$, a binarity fraction near $0.419\pm0.021$, and an extinction ($A_V$) of approximately $0.995\pm0.058$ mag for an $R_V$ value of around $3.064\pm0.102$. We also fitted the radial surface density profile and conducted orbit analysis of the cluster using galpy. And finally found that the star formation scenarios are not observed in the open star cluster NGC 6416.
Após o desenvolvimento do Modelo Padrão da Cosmologia, o Modelo do Big Bang, ao que tudo indicava, havia-se construído uma teoria satisfatória capaz de descrever a evolução do Universo a partir de um estado quente e denso inicial. No entanto, algumas questões em aberto levaram à proposta do modelo da Inflação Cosmológica, o qual descreve uma expansão acelerada no Universo antigo que teria durado uma fração de segundo, e após a qual o Universo teria seguido sua expansão conforme previsto pelo Modelo do \textit{Big Bang}. Embora hoje existam alternativas à Inflação que são capazes de resolver as mesmas questões, a Inflação foi a primeira teoria com a qual foi possível se fazer previsões consistentes sobre a estrutura do Universo em larga escala, como a distribuição de galáxias, aglomerados etc., ao fornecer uma descrição para a origem das mesmas. Neste artigo será apresentado o Modelo Inflacionário, desde uma perspectiva histórica e também matemática. Serão abordadas as críticas e desafios que acercam este modelo atualmente e também as perspectivas futuras no que se refere a testes do modelo inflacionário com os novos experimentos.
Adaptive Optics (AO) systems have become integral for ground-based astronomy. Based on the scientific case, there are various flavours of AO systems. Measuring the turbulence strength profile ($C_N^2(h)$) and other site characteristics is essential before selecting a site or implementing certain types of AO systems. We used an iterative deconvolution procedure on long-exposure H-$α$ images of the Sun to determine the isoplanatic patch size during the daytime. Then, we determined the relationship between turbulence along different directions and also obtained an analytical estimate of the $C_N^2(h)$ profile.
Apresentamos neste artigo um panorama da nucleossíntese cosmológica, estelar e catastrófica que leva a povoar a Tabela Periódica do elementos criada por D. Mendeleev há mais de um século.
Er et al. (2021) recently proposed a two-planet solution to account for eclipse timing variations (ETVs) observed from the sdB binary NY Virginis. We tested the proposed planetary system for orbit stability using both numerical simulations and chaotic behavior analysis. The best-fit orbits, as well as those with parameters varying by the published uncertainty range in each parameter, were unstable on a timescale much less than the presumed lifetime of the PCEB phase ($\sim$100 Myr). suggesting that the proposed circumbinary companions fail to provide a complete explanation for the observed ETVs.
Um quarto do conteúdo energético do Universo está na forma de matéria escura. A natureza dessa matéria ainda é um enigma, mas há poucas dúvidas de que sua solução requer uma extensão do modelo padrão da física de partículas, com a inclusão de novas partículas elementares e talvez novas interações. Após rever algumas evidências cosmológicas indicando a existência dessa componente escura do cosmos, mostramos como as ferramentas teóricas já disponíveis podem ser utilizadas para explicar sua origem no Universo primordial, e discutimos brevemente alguns dos cenários de candidatos mais promissores a essa forma de matéria. Uma importante conclusão é que o estudo desse setor escuro pode lançar nova luz sobre alguns dos enigmas relacionados ao comportamento da matéria bariônica usual.
It is difficult to study the interiors of terrestrial planets in the Solar System and the problem is magnified for distant exoplanets. However, sometimes nature is helpful. Some planetary bodies are torn to fragments and consumed by the strong gravity close to the descendants of Sun-like stars, white dwarfs. We can deduce the general composition of the planet when we observe the spectroscopic signature of the white dwarf. Most planetary fragments that fall into white dwarfs appear to be rocky with a variable fraction of associated ice and carbon. These white dwarf planetary systems provide a unique opportunity to study the geology of exoplanetary systems.
O presente artigo visa estudar como o direito internacional regula as atividadesno espaço cósmico, na lua e em outros corpos celestes. Também será comentadoquestões sobre o regime de propriedade aplicado no espaço cósmico, sua evoluçãoe aplicação hoje em dia.
In this paper we discuss the calculation of chemical abundances in planetary nebulae and H II regions through ionization correction factors (ICFs). We review the first ICFs proposed in the literature based on ionization potential similarities and we present the most recent ICFs derived from large sample of photoionization models. We also discuss some of the considerations that have to be kept in mind when using ICFs to compute the chemical composition of ionized nebulae.
We present some preliminary results of our ongoing project about planetary systems around S-stars in the vicinity of Sgr A* black hole. Since S-stars might have migrated in the Galactic Centre (GC) from elsewhere, they probably still keep their planetary systems throughout their voyage. In this work, we study the destiny of their putative planetary systems after close interaction with the central black hole of our galaxy.
In order to understand the Galactic structure, we perform a statistical analysis of the distribution of various cluster parameters based on an almost complete sample of Galactic open clusters yet available. The geometrical and physical characteristics of a large number of open clusters given in the MWSC catalogue are used to study the spatial distribution of clusters in the Galaxy and determine the scale height, solar offset, local mass density and distribution of reddening material in the solar neighbourhood. We also explored the mass-radius and mass-age relations in the Galactic open star clusters. We find that the estimated parameters of the Galactic disk are largely influenced by the choice of cluster sample.
Precise and, if possible, accurate characterization of exoplanets cannot be dissociated from the characterization of their host stars. In this chapter we discuss different methods and techniques used to derive fundamental properties and atmospheric parameters of exoplanet-host stars. The main limitations, advantages and disadvantages, as well as corresponding typical measurement uncertainties of each method are presented.
Spectral line inversion codes are tools used to interpret spectropolarimetric data; in general, their function is to analyze a set of observed Stokes profiles, and infer the physical properties of the line-formation region in which the Stokes profiles were formed. For the SOLIS/VSM 6302v pipeline, the inversion is based on a Milne-Eddington model atmosphere, optimized to reproduce the observed Stokes profiles of both Fe I lines at 6301.5 and 6302.5 Angstroms . This document provides a detailed overview of the SOLIS/VSM remix of the VFISV (Very Fast Inversion of the Stokes Vector) inversion code, as it is implemented in the SOLIS/VSM pipeline environment.
The fates of planetary systems provide unassailable insights into their formation and represent rich cross-disciplinary dynamical laboratories. Mounting observations of post-main-sequence planetary systems necessitate a complementary level of theoretical scrutiny. Here, I review the diverse dynamical processes which affect planets, asteroids, comets and pebbles as their parent stars evolve into giant branch, white dwarf and neutron stars. This reference provides a foundation for the interpretation and modelling of currently known systems and upcoming discoveries.
In this paper I present an overview of the main observational properties of a special class of exotic objects (the so-called Blue Straggler Stars, BSSs) in Galactic Globular Clusters (GCs). The BSS specific frequency and their radial distribution are discussed in the framework of using this stellar population as probe of GC internal dynamics. In particular, the shape of the BSS radial distribution has been found to be a powerful tracer of the dynamical evolution of stellar systems, thus allowing the definition of an empirical "clock" able to measure the dynamical age of stellar aggregates from pure observational properties.