Fisica

HW Vir systems are rare evolved eclipsing binaries composed of a hot compact star and a low-mass main sequence star in a close orbit. These systems provide a direct way to measure the fundamental properties, e.g. masses and radii, of their components, hence they are crucial in studying the formation of subdwarf B stars and low-mass white dwarfs, the common-envelope phase and the pre-phase of cataclysmic variables. Here, we present a detailed study of HS 2231+2441, an HW Vir type system, by analysing BVR C I C photometry and phase-resolved optical spectroscopy. The spectra of this system, which are dominated by the primary component features, were fitted using non-local thermodynamic equilibrium models providing an effective temperature T eff = 28 500 ± 500 K, surface gravity log g = 5.40 ± 0.05 cm s −2 and helium abundance log (n(He)/n(H)) = −2.52 ± 0.07. The geometrical orbit and physical parameters were derived by simultaneously modelling the photometric and spectroscopic data using the Wilson–Devinney code. We derive two possible solutions for HS 2231+2441 that provide the component masses: M 1 = 0.19 M and M 2 = 0.036 M or M 1 = 0.288 M and M 2 = 0.046 M. Considering the possible evolutionary channels for forming a compact hot star, the primary of HS 2231+2441 probably evolved through the red-giant branch scenario and does not have a helium-burning core, which is consistent with a low-mass white dwarf. Both solutions are consistent with a brown dwarf as the secondary.

The brightness variation of the stars is an object of study in astronomy and astrophysics for representing the rich inherent source of physical information. Launched in 2009, the Kepler spacecraft with the primary mission of identifying equivalent to the Earth by the Sun transits also gave birth to thousands of light curves of targets of scientific interest. KIC 10670103, the richest pulsating sub-dwarf B (sdB) star, is one of the many stars identified by the mission. With 3.72 yr of Kepler spacecraft observations, we analysed in this paper the light curve of this sdB star, by the detrended fluctuation analysis (DFA) method. The behaviour of this pulsating star reveals self-affinity at specific timescales , with changes in DFA exponent, α DFA. This fact suggests some light variability in KIC 10670103, as for example, from a non-periodic to a periodic case, among others. Therefore, we propose to connect the pulsation pattern of the KIC 10670103 star, which presents trends and non-stationarity, with the α DFA exponent. In this sense, we obtain five values of α DFA related to the light variability properties of KIC 10670103. A pictorial figure will describe the relationship between these variables.

The matter Origin of Life is always applied at the basic school but quite transient, limited to
describe assumptions and / or theories without exploring the scientific basis and the students' prior
knowledge that would enable a meaningful learning. These theories highlight the Panspermia,
proposed by Arrhenius in 1903, which according to him, spores, called seeds, could have seeded life
on Earth brought by solar winds. Today, with the advancement of research in Astronomy, especially in
Astrobiology, has expanded this concept, the theory has gained by means of space missions,
particularly the missions to Mars, important information for its understanding. The teacher can,
through the lifting of the student already knows about it, reframe concepts applying strategies that
allow him to be with new information, integrated into contemporary society, but also to contextualize
their conceptions giving meaning to learning. This work aims to build educational materials on
missions to Mars as pedagogical strategies that can serve as anchors in assigning new meanings on
the Origin of Life in the Universe.

We have carried out a campaign to characterize the hot Jupiters WASP-5b, WASP-44b and WASP-46b using multiband photometry collected at the Observat´orio do Pico Dos Dias in Brazil.We have determined the planetary physical properties and new transit ephemerides for these systems. The new orbital parameters and physical properties of WASP-5b and WASP-44b are consistent with previous estimates. In the case of WASP-46b, there is some quota of,disagreement between previous results. We provide a new determination of the radius of this planet and help clarify the previous differences. We also studied the transit time variations including our new measurements. No clear variation from a linear trend was found for the systemsWASP-5b andWASP-44b. In the case ofWASP-46b, we found evidence of deviations indicating the presence of a companion but statistical analysis of the existing times points to a signal due to the sampling rather than a new planet. Finally, we studied the fractional radius variation as a function of wavelength for these systems. The broad-band spectrums of WASP-5b and WASP-44b are mostly flat. In the case of WASP-46b we found a trend, but further measurements are necessary to confirm this finding.

We report the detection of pulsations with an approximately 124 s period in V2116 Oph, the optical
counterpart of the low-mass X-ray binary GX 1+4. The pulsations are sinusoidal with modulation amplitude of
up to 4% in blue light and were observed in 10 different observing sessions during 1996 April–August using a
CCD photometer at the 1.6 m and 0.6 m telescopes of Laborato´rio Nacional de Astrofı´sica, in Brazil. The
pulsations were also observed with the UBVRI fast photometer. With only one exception, the observed optical
periods are consistent with those observed by the BATSE instrument on board the Compton Gamma Ray
Observatory at the same epoch. There is a definite correlation between the observability of pulsations and the
optical brightness of the system: V2116 Oph had R magnitude in the range 15.3–15.5 when the pulsed signal was
detected, and R 5 16.0 –17.7 when no pulsations were present. The discovery makes GX 114 only the third of
about 40 accretion-powered X-ray pulsars to be firmly detected as a pulsating source in the optical. The presence
of flickering and pulsations in V2116 Oph adds strong evidence for an accretion disk scenario in this system. The
absolute magnitude of the pulsed component on 1996 May 27 is estimated to be MV = 21.5. The implied
dimensions for the emitting region are 1.1 RJ, 3.2 RJ, and 7.0 RJ, for blackbody spectral distributions with T 5
10^5 K, 2 3 104 K, and 1 3 104 K, respectively.

We report strong evidence for a »304 day periodicity in the spin history of the accretion-powered pulsar GX1+4 that is most probably associated with the orbital period of the system. We have used data from the Burst and Transient Source Experiment on the Compton Gamma-Ray Observatory to show a clear periodic modulation of the pulsar frequency from 1991 to date, in excellent agreement with the ephemeris proposed by Cutler, Dennis,& Dolan in 1986. Our results indicate that the orbital period of GX 114 is 303.851.1 days, making it the widest known low-mass X-ray binary system by more than 1 order of magnitude and putting this long-standing
question to rest. A likely scenario for this system is an elliptical orbit in which the neutron star decreases its spin-down rate (or even exhibits a momentary spin-up behavior) at periastron passages due to the higher torque exerted by the accretion disk onto the magnetosphere of the neutron star. These results are not inconsistent with either the X-ray pulsed flux light curve measured by BATSE during the same epoch or the X-ray flux history from the All-Sky Monitor on board the Rossi X-Ray Timing Explorer.

We have discovered that V729 Sgr, an object listed as a possible rapid irregular variable in
the fourth edition of the General Catalogue of Variable Stars, is an eclipsing cataclysmic variable with an orbital period of 0.1734055 days and an eclipse depth of 0.2È0.5 mag. The shape of the light curve is quite variable. When observed in the R Ðlter the light curve presents a pronounced sinusoidal modulation with an amplitude of D0.4È0.5 mag. In addition, brightness variations with timescales and characteristics suggesting dwarf nova eruptions are seen in the historical photometric data and in the our own data. We classify V729 Sgr as a new member of dwarf nova class, possibly of Z Cam type.

A balloon experiment conducted on December 20, 1994, in the South Atlantic Anomaly (SAA) region, detected events with increases in x-ray flux due to electron precipitation coincident with a mild substorm activity. For the first time in the SAA, the analysis of the x-ray flux associated with the electron precipitation and the geomagnetic H-field component showed simultaneous Pc4 pulsations at periods in the range 95 to 100s. Analysis of a prominent precipitation event of this flight showed direct correlation between the pulsation strength in the x-ray and in the magnetic data and are related to the intensity of the precipitation. While the substorm associated electric fields and currents in the ionosphere can induce amplification of Pc4 pulsations, the x-ray pulsations due to electron precipitation may be related to wave modulated pitch angle scatterings.

Optical and near infrared spectroscopy of the stars DQ Ser and DT Ser are presented. DQ Ser shows a late-type continuum (M3 - M5) with emission lines of Balmer series, HeI, HeII, [OIII], OI and CaII triplet while DT Ser presents a earlier spectral type with emission of Balmer lines, HeI, HeII and [OIII]. DT Ser is a faint  star 5 arcsec from a  G companion. We suggest it to be a yellow symbiotic star.

As alternativas energéticas por meio de fontes renováveis de energia tornaram-se objeto de pesquisas no mundo inteiro, devido ao crescimento da população e das atividades industriais, que trazem como conseqüência a demanda, cada vez maior, de energia e o aumento do descarte de resíduos sólidos, que, por sua vez, vão gerar problemas ambientais e relativos à oferta e aos custos da energia. Analisando o cenário energético do Brasil, verificamos que se a economia caminhar a um ritmo anual de crescimento de 4,1%, ante uma taxa mundial de 3%, em 2030 nossas necessidades de energia vão aumentar em 4,3% ao ano. Outro ponto é o ritmo atual de crescimento do PIB (+/-5%), que impõe a necessidades de adicionar 5 mil MW/ano à oferta de energia. Até 2030 será preciso contar com praticamente o dobro da capacidade de geração atual. A combinação de demanda crescente, falta de capacidade para expansão nos setores tradicionais, além dos obstáculos financeiros, sócio-econômicos e ambientais, indica que o fornecimento futuro de energia  no Brasil dependerá cada vez mais nas fontes alternativas de energia, o que é bom para as instalações de LFG, se as políticas para energia e a legislação correlata permitir que esses novos projetos de energia ‘verde’ com preços de mercado o que incentivará o seu
desenvolvimento. A busca por energias alternativas possui também a finalidade
de diminuir a dependência dos combustíveis fósseis, fornecendo soluções ambientalmente corretas e sustentadas para colaborar com a matriz energética dos países e reduzir os  impactos globais provocados pela queima dos combustíveis fósseis. Neste sentido, a utilização do biogás como fonte renovável e sustentável de energia, que pode ocorrer
através de resíduos sólidos urbanos, resíduos rurais, efluentes domésticos e industriais, permite diversificar a matriz energética nacional, e não apresenta benefícios apenas à
empresa investidora, mas também, a sociedade, através da oferta de energia elétrica e ao meio ambiente, reduzindo as emissões de gases do efeito estufa, sendo, portanto, um
instrumento eficaz para auxiliar o desenvolvimento econômico sustentável da região.
Logo, apresentaremos um biogás que é uma fonte alternativa, renovável, disponível,
próxima aos centros consumidores de energia elétrica e até o presente, pouco utilizada, que poderá suprir em partes as necessidades da população

A criação de valor agregado aos produtos sem o comprometimento do atendimento das necessidades das gerações futuras tem sido uma preocupação de diversas organizações no mundo. Neste cenário a inovação sustentável torna-se um fator competitivo para as organizações que enxergam na sustentabilidade diversas oportunidades para adquirir vantagens competitivas. O acúmulo crescente dos resíduos sólidos urbanos – RSU´s é um dos graves problemas ambientais  enfrentados pelos grandes centros urbanos, situação essa que tende a agravar-se com o crescimento da população, das atividades industriais e com o aumento do consumo de bens descartáveis. Devido  a grande quantidade produzida de RSU, principalmente nas grandes cidades a implantação de sistemas de destinação final torna-se uma ação inevitável, sendo que a alternativa economicamente mais viável e ambientalmente mais segura é a construção de aterros sanitários. O acúmulo dos resíduos em aterros propicia a formação de um grande biodigestor que, por sua vez, têm como subproduto o biogás, gerado pela decomposição do lixo. Os principais constituintes do biogás são:  dióxido de carbono (CO ) e o gás metano (CH ), gases esses que possuem um grande potencial de aquecimento global (global warming potencial – GWP), e que estão entre os principais  responsáveis pelo efeito estufa. A emissão descontrolada deste subproduto pode ser uma ameaça ao ambiente local, pois traz conseqüências como: danos à vegetação, geração de odores desagradáveis e riscos de explosão. Concentrações em torno de 5% a 15% do biogás no ar são suficientes para causar os danos supracitados além de por em riscos à saúde da população circunvizinha do aterro.  Em virtude desses riscos é que o controle adequado do biogás com a implementação de tecnologias limpas deve tornar-se uma prioridade para os gestores dos municípios. Nesse contexto, este trabalho apresentará uma solução sustentável para o acumulo dos RSU´s do Município de Feira de Santana. A escolha por este município deve-se ao fato de o mesmo integrar o seleto grupo das  cidades do Brasil que possui um Aterro Sanitário que desenvolve suas atividades seguindo critérios do Mecanismo de Desenvolvimento Limpo. Localizada no interior do Estado da Bahia, a cidade  comporta mais de meio milhão de habitantes, tendo seu aterro sanitário projeções anuais de mais de 150 mil toneladas de RSU´s. Apresentaremos quais são os benefícios sociais e econômicos que a queima controlada desse biogás pode trazer para uma região, e quanto de receita em CERs –Certificados de Emissões Reduzidas, popularmente conhecidos como: “créditos de carbono” é  gerado pelo projeto de queima, através do Mecanismo de Desenvolvimento Limpo - MDL. Esse rendimento obtido com os créditos de carbono poderá se tornar um atrativo para as cidades que  possuem lixões e aterros controlados, que a fim de gerar uma receita adicional, darão inicio ao devido manejo dos RSU e aos licenciamentos necessários. Esse pode ser o inicio de um processo  ambiental muito mais amplo, onde o RSU será corretamente manejado para geração do biogás, que  poderá ser aproveitado de diversas formas, como por exemplo: geração de calor, produção de  eletricidade, uso em caldeiras, motores de combustão interna, tratamento do chorume, iluminação pública, uso em fogões industriais e residenciais, e outros conversores de energia.

We study the behavior of the numbers in 412 light curves of cataclysmic variables, x-ray
binary systems, galaxies, pulsars, supernovae remnants and other x-ray sources present
in the public data collected by the instrument All Sky Monitor on board of the satellite
Rossi x-ray timing explorer. The temporal light curves were analyzed applying Newcomb-
Benford Law. The first digit of the x-ray light curves coming from astrophysical systems
obeys the Newcomb-Benford Law as an intrinsic behavior. The nonextensive statistical
mechanics behavior of astrophysical sources seem to be the cause for these sources to
obey the Newcomb-Benford law. Some x-ray binary systems, however, do not follow this
behavior. These systems obey either a gaussian or a bimodal distribution.

The colours of pulsed and non-pulsed light in V2116 Oph have been measured with the UBVRI photometer of the Laboratorio Nacional de Astroffsica, in Brazil. The symbiotic binary was in an optical bright state with V ~17. If the blue component in the spectrum of V2116 Oph follows the prescription for a standard optically thick accretion disc spectrum, its contribution to the light of the system at 6600 A is ~20 times the contribution of the red giant, with E(B - V) = 2.1 ± 0.1 mag and a distance of 8.3 kpc. The pulsed component is estimated to have Mv ~-1.7, implying characteristic sizes (for blackbody emission) of 1.4, 4.3 and 9.3 R0' for temperatures TBB = 100000, 20000 and 10 000 K, respectively.

We study the temporal correlations in 412 light curves of X-ray sources present in the public data collected by the instrument All Sky Monitor on board of the satellite Rossi X-ray timing explorer. The temporal light curves were analyzed applying detrended fluctuation analysis. The fluctuation of the X-ray light curves coming from astrophysical systems present temporal self-affinity as an intrinsic behavior. We present the results from cataclysmic variables, X-ray binary systems, galaxies, pulsars and other X-ray sources independently and we observe a universal behavior in the long-range scaling exponent

A inclusão social é um dos principais desafios da sociedade moderna. No que se
refere à inclusão científica e tecnológica grande parte da população vive à margem do
conhecimento inerente ao desenvolvimento das ciências e da tecnologia (C&T), se tornando um usuário passivo dos benefícios oriundos dos avanços nestas áreas. Este projeto tem como objetivos a difusão e popularização da ciência utilizando Astronomia e
inclusão sócio-cultural das populações nos municípios visitados pelo projeto, em particular os municípios distantes dos grandes centros. Para realização das atividades são utilizados um planetário inflável com um projetor STARLAB, e alguns experimentos que tratam de fenômenos de astronomia e física.