Animação e rock'n'roll usados para facilitar ensino de astronomia e química

Por sua característica multidisciplinar, a astronomia tem sido amplamente utilizada na aplicação da pesquisa científica no ensino de ciências naturais. As chamadas por projetos de ensino e divulgação científica, visando a produção de materiais didáticos, configuram-se em excelentes oportunidade de aliar o fascínio da população pelos astros e a informação que estes podem trazer sobre conceitos básicos das ciências fundamentais. No presente trabalho descrevemos a experiência em criar materiais didáticos em linguagem atrativa aos jovens (livros de história em quadrinhos; filmes de animação) com o objetivo de ampliar a cultura cientifica entre o público em geral. Para os estudantes da graduação, nossos projetos fazem parte das açoes afirmativas que buscam diminuir a evasão e estimular a conclusão no tempo ideal. Esse artigo é dedicado à descrição da metodologia adotada e apresentação de alguns exemplos dos resultados alcançados, nesse tipo de atuação “antes” e “depois” do ingresso do estudante na graduação.Due to its multidisciplinary character, astronomy has been subject of educational projects that use scientific research to improve the learning of natural sciences. The financial support in the form of Announcements of Opportunities, devoted to the production of teaching and outreach material, are the best way to combine the fascination that people have about the stars, with the information that these objects can bring concerning the basic concepts related to fundamental sciences. In the present work, we describe the experience in developing educational resources by adopting modern communication language (comics, animations) that is attractive among young people. Our goal is to enlarge the scientific culture of the citizens. For undergraduate students, our projects aim to diminish the evasion, as well as to promote the course conclusion in the ideal period. The paper is dedicated to describe the adopted methodology and to report the partial results of acting “before “and “after” the student entrance in the undergraduate course

X-ray sources associated with young stellar objects in the star forming region CMaR1

In previous Works we studied the star forma on scenario in the molecular cloud\ud Canis\ud Major\ud R1\ud (CMa\ud R1),\ud derived\ud from\ud the\ud existence\ud of\ud young\ud stellar\ud popula<on\ud groups\ud near\ud the\ud Be\ud stars\ud Z\ud CMa\ud and\ud GU\ud CMa,\ud using\ud data\ud from\ud the\ud ROSAT\ud X-­‐ray\ud satellite.\ud In\ud order\ud to\ud inves<gate\ud the\ud nature\ud of\ud these\ud objects\ud and\ud to\ud test\ud a\ud possible\ud scenario\ud of\ud sequen<al\ud star\ud forma<on\ud in\ud this\ud region,\ud four\ud fields\ud (each\ud 30\ud arcmin\ud diameter,\ud with\ud some\ud overlap\ud –\ud Fig.\ud 1)\ud have\ud been\ud observed\ud with\ud the\ud XMM-­‐Newton\ud satellite,\ud with\ud a\ud sensi<vity\ud about\ud 10\ud <mes\ud be_er\ud than\ud ROSAT.\ud The\ud XMM-­‐Newton\ud data\ud are\ud currently\ud under\ud analysis.\ud Preliminary\ud results\ud indicate\ud the\ud presence\ud of\ud about\ud 324\ud sources,\ud most\ud of\ud them\ud apparently\ud having\ud one\ud or\ud more\ud near-­‐infrared\ud counterparts\ud showing\ud typical\ud colors\ud of\ud young\ud stars.\ud The\ud youth\ud of\ud the\ud X-­‐ray\ud sources\ud was\ud also\ud confirmed\ud by\ud X-­‐ray\ud hardness\ud ra<o\ud diagrams\ud (XHRD),\ud in\ud different\ud energy\ud bands,\ud giving\ud an\ud es<mate\ud of\ud their\ud LX/Lbol\ud ra<os.\ud In\ud addi<on\ud to\ud these\ud results,\ud we\ud present\ud a\ud detailed\ud study\ud of\ud the\ud XMM\ud field\ud covering\ud the\ud cluster\ud near\ud Z\ud CMa.\ud Several\ud of\ud these\ud sources\ud were\ud classified\ud as\ud T\ud Tauri\ud and\ud Herbig\ud Ae/Be\ud stars,\ud using\ud op<cal\ud spectroscopy\ud obtained\ud with\ud Gemini\ud telescopes,\ud in\ud order\ud to\ud validate\ud the\ud use\ud of\ud XHRD\ud applied\ud to\ud the\ud en<re\ud sample.\ud This\ud classifica<on\ud is\ud also\ud used\ud to\ud confirm\ud the\ud rela<on\ud between\ud the\ud luminosi<es\ud in\ud the\ud near-­‐infrared\ud and\ud X-­‐ray\ud bands\ud expected\ud for\ud the\ud T\ud Tauri\ud stars\ud in\ud CMa\ud R1.\ud In\ud the\ud present\ud work\ud we\ud show\ud the\ud results\ud of\ud the\ud study\ud based\ud on\ud the\ud spectra\ud of\ud about\ud 90\ud sources\ud found\ud nearby\ud Z\ud CMa.\ud We\ud checked\ud that\ud the\ud X-­‐ray\ud spectra\ud (0.3\ud to\ud 10\ud keV)\ud of\ud young\ud objects\ud is\ud different\ud from\ud that\ud observed\ud in\ud field\ud stars\ud and\ud extragalac<c\ud objects.\ud Some\ud of\ud the\ud candidates\ud also\ud have\ud light\ud curve\ud showing\ud flares\ud that\ud are\ud typical\ud of\ud T\ud Tauri\ud stars,\ud which\ud confirms\ud the\ud young\ud nature\ud of\ud these\ud X-­‐ray\ud sources.CNP

A X-ray view of the young star population in CMA R1

In previous works we studied the star formation scenario in the molecular cloud Canis Major R1 (CMa R1), revealing the existence of young stellar groups near the Be stars Z CMa and GU CMa. Using data from the ROSAT X-ray satellite, Gregorio-Hetem et al. (2009) - GH2009 - discovered in this region young stellar objects (YSOSs) mainly grouped in two clusters of different ages. In order to investigate the nature of these objects and to test a possible scenario of sequential star formation in this region, four fields (each 30' diameter, with some overlap - (Fig. 1) have been observed with the XMM-Newton satellite that has a sensitivity about 10 times better than ROSAT.Resumo publicado no periódico: Revista Mexicana de Astronomía y Astrofísica. Serie de Conferencias, v. 44, p. 32, 2014

The alignment of the polarization of HAe/Be stars with the interstellar magnetic field

We present a study of the correlation between the direction of the symmetry axis of the circumstellar material around intermediate mass young stellar objects and that of the interstellar magnetic field. We use CCD polarimetric data on 100 Herbig Ae/Be stars. A large number of them shows intrinsic polarization, which indicates that their circumstellar envelopes are not spherical. The interstellar magnetic field direction is estimated from the polarization of field stars. There is an alignment between the position angle of the Herbig Ae/Be star polarization and that of the field stars for the most polarized objects. This may be an evidence that the ambient interstellar magnetic field plays a role in shaping the circumstellar material around young stars of intermediate mass and/or in defining their angular momentum axis.Comment: ApJ accepte

The Gemini NICI Planet-Finding Campaign

Our team is carrying out a multi-year observing program to directly image and characterize young extrasolar planets using the Near-Infrared Coronagraphic Imager (NICI) on the Gemini-South 8.1-meter telescope. NICI is the first instrument on a large telescope designed from the outset for high-contrast imaging, comprising a high-performance curvature adaptive optics system with a simultaneous dual-channel coronagraphic imager. Combined with state-of-the-art observing methods and data processing, NICI typically achieves ~2 magnitudes better contrast compared to previous ground-based or space-based programs, at separations inside of ~2 arcsec. In preparation for the Campaign, we carried out efforts to identify previously unrecognized young stars, to rigorously construct our observing strategy, and to optimize the combination of angular and spectral differential imaging. The Planet-Finding Campaign is in its second year, with first-epoch imaging of 174 stars already obtained out of a total sample of 300 stars. We describe the Campaign's goals, design, implementation, performance, and preliminary results. The NICI Campaign represents the largest and most sensitive imaging survey to date for massive (~1 Mjup) planets around other stars. Upon completion, the Campaign will establish the best measurements to date on the properties of young gas-giant planets at ~5-10 AU separations. Finally, Campaign discoveries will be well-suited to long-term orbital monitoring and detailed spectrophotometric followup with next-generation planet-finding instruments.Comment: Proceedings of the SPIE, vol 7736 (Advances in Adaptive Optics, San Diego, CA, June 2010 meeting), in pres

The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets Around Debris Disk Stars

We have completed a high-contrast direct imaging survey for giant planets around 57 debris disk stars as part of the Gemini NICI Planet-Finding Campaign. We achieved median H-band contrasts of 12.4 mag at 0.5" and 14.1 mag at 1" separation. Follow-up observations of the 66 candidates with projected separation < 500 AU show that all of them are background objects. To establish statistical constraints on the underlying giant planet population based on our imaging data, we have developed a new Bayesian formalism that incorporates (1) non-detections, (2) single-epoch candidates, (3) astrometric and (4) photometric information, and (5) the possibility of multiple planets per star to constrain the planet population. Our formalism allows us to include in our analysis the previously known Beta Pictoris and the HR 8799 planets. Our results show at 95% confidence that 5MJup planet beyond 80 AU, and 3MJup planet outside of 40 AU, based on hot-start evolutionary models. We model the population of directly-imaged planets as d^2N/dMda ~ m^alpha a^beta, where m is planet mass and a is orbital semi-major axis (with a maximum value of amax). We find that beta 1.7. Likewise, we find that beta < -0.8 and/or amax < 200 AU. If we ignore the Beta Pic and HR 8799 planets (should they belong to a rare and distinct group), we find that 3MJup planet beyond 10 AU, and beta < -0.8 and/or alpha < -1.5. Our Bayesian constraints are not strong enough to reveal any dependence of the planet frequency on stellar host mass. Studies of transition disks have suggested that about 20% of stars are undergoing planet formation; our non-detections at large separations show that planets with orbital separation > 40 AU and planet masses > 3 MJup do not carve the central holes in these disks.Comment: Accepted to ApJ on June 24, 2013. 67 pages, 17 figures, 12 table

Optical polarization and near IR photometry of the proto-planetary nebula Hen 3-1475

We present BVRI CCD aperture polarization and near-infrared photometry of the proto-planetary nebula Hen 3-1475. Its intrinsic polarization is high and shows a strong spectral dependence. The position angles in all bands are perpendicular to the axis of the observed bipolar structure. A Monte Carlo code is used to model the intrinsic polarization of \hhe. Using disk dimensions and other constraints suggested by previous works, we are able to reproduce the observations with an optically thick disk composed by grains with a power-law size distribution ranging from 0.06 to 0.22 um. We also reliably estimate the foreground polarization from hundreds of stars contained in the CCD images. It is parallel to the intrinsic polarization of Hen 3-1475. Possible implications of this result are discussed. From IR observations, we estimate a interstellar reddening, A(V), of about 3.2.Comment: ApJ accepted, 16 pages, 6 figure