18/3/2010
Agência FAPESP – Um grupo internacional de cientistas, com participação brasileira, descobriu um exoplaneta (ou seja, além do Sistema Solar) com temperaturas superficiais consideradas estáveis e moderadas.
As temperaturas variam entre -20º C e 160º C, com a máxima muito acima do encontrado na Terra, mas muito abaixo desses planetas, chamados de “Júpiter quente”. O planeta foi descoberto por observações feitas com o telescópio espacial CoRoT.
Cientistas descobrem primeiro exoplaneta com temperatura e outras características encontradas no Sistema Solar. CoRoT-9b tem o tamanho aproximado de Júpiter e órbita semelhante à de Mercúriofoto: CoRoT)
O novo planeta, denominado CoRoT-9b, lembra bastante os encontrados no Sistema Solar. Tem o tamanho aproximado de Júpiter e uma órbita semelhante à de Mercúrio.
São conhecidos, atualmente, cerca de 400 exoplanetas, dos quais 70 orbitam uma estrela central. Esses planetas têm órbitas muito curtas ou excêntricas, com temperaturas superficiais extremas.
Em artigo publicado na Nature, Sylvio Ferraz-Mello, professor titular do Instituto de Astronomia, Geofísica e Ciências Atmosféricas, e colegas de diversos países descrevem o planeta, que tem uma órbita de 95 dias em torno de uma estrela parecida com o Sol.
Segundo os autores do estudo, as características do planeta se encaixam nos modelos padrões de evolução e ele provavelmente tem uma composição interna parecida com a de Júpiter ou a de Saturno.
“O CoRoT-9b é o primeiro exoplaneta até hoje encontrado que realmente se assemelha aos planetas em nosso Sistema Solar”, apontou Hans Deeg, do Instituto de Astrofísica de Canárias e primeiro autor do artigo.
“Esse é o primeiro exoplaneta cujas propriedades podemos estudar em profundidade. Ele pode se tornar a pedra de Roseta da pesquisa em exoplanetas”, disse Claire Moutou, do Departamento de Astrofísica da Universidade de La Laguna, na Espanha, um dos autores do estudo.
“Como no caso de nossos planetas gigantes, Júpiter e Saturno, o novo planeta é formado basicamente de hidrogênio e hélio. E pode conter outros elementos, como água e pedras em elevadas temperaturas e pressão, em um total de até 20 vezes a massa da Terra”, disse Tristan Guillot, do Observatório da Côte d’Azur.
O CoRoT-9b passa em frente à sua estrela a cada 95 dias – conforme observado da Terra. Esse “trânsito" dura cerca de 8 horas e fornece aos astrônomos muita informação adicional do planeta. Esses detalhes são muito importantes, uma vez que o planeta compartilha muitas características com a maioria dos exoplanetas descobertos até hoje.
O CoRoT, operado pelo Centro Nacional de Estudos Espaciais da França, ajudou os cientistas a descobrir o planeta após 145 dias de observações durante o verão de 2008.
O artigo A transiting giant planet with a temperature between 250 K and 430 K (vol 464 | 18 March 2010 | doi:10.1038/nature08856), de Eudald Carbonell, de Hans Deeg e outros, pode ser lido por assinantes da Nature em www.nature.com.
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A transiting giant planet with a temperature between 250 K and 430 K
H. J. Deeg1,2, C. Moutou3, A. Erikson4, Sz. Csizmadia4, B. Tingley1,2, P. Barge3, H. Bruntt5, M. Havel6, S. Aigrain7,8, J. M. Almenara1,2, R. Alonso9, M. Auvergne5, A. Baglin5, M. Barbieri3,10, W. Benz11, A. S. Bonomo3, P. Bordé12, F. Bouchy13,14, J. Cabrera4,15, L. Carone16, S. Carpano17, D. Ciardi18, M. Deleuil3, R. Dvorak19, S. Ferraz-Mello20, M. Fridlund17, D. Gandolfi21, J.-C. Gazzano3, M. Gillon22, P. Gondoin17, E. Guenther21, T. Guillot6, R. den Hartog17, A. Hatzes21, M. Hidas23,24, G. Hébrard13, L. Jorda3, P. Kabath4,28, H. Lammer25, A. Léger12, T. Lister23, A. Llebaria3, C. Lovis9, M. Mayor9, T. Mazeh26, M. Ollivier12, M. Pätzold16, F. Pepe9, F. Pont7, D. Queloz9, M. Rabus1,2,28, H. Rauer4,27, D. Rouan5, B. Samuel12, J. Schneider15, A. Shporer26, B. Stecklum21, R. Street23, S. Udry9, J. Weingrill25 & G. Wuchterl21
Instituto de Astrofísica de Canarias, C. Via Lactea S/N, E-38205 La Laguna, Tenerife, Spain
Department de Astrofísica, Universidad de La Laguna, E-38200 La Laguna, Tenerife, Spain
Laboratoire d’Astrophysique de Marseille, CNRS and Université de Provence, 38 rue Frédéric Joliot-Curie, F-13388 Marseille cedex 13, France
Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, D-12489 Berlin, Germany
LESIA, Observatoire de Paris, CNRS, Place J. Janssen, 92195 Meudon cedex, France
Université de Nice-Sophia Antipolis, Observatoire de la Côte d'Azur, CNRS UMR 6202, 06304 Nice cedex 4, France
School of Physics, University of Exeter, Exeter, EX4 4QL, UK
Oxford Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
Observatoire de l’Université de Genève, 51 chemin des Maillettes, CH 1290 Sauverny, Switzerland
Dipartimento di Astronomia, Università di Padova, 35122 Padova, Italy
Universität Bern, Physics Institute, Sidlerstrasse 5, CH 3012 Bern, Switzerland
Institut d’Astrophysique Spatiale, Université Paris XI, F-91405 Orsay, France
IAP, 98bis boulevard Arago, F-75014 Paris, France
Observatoire de Haute-Provence, CNRS/OAMP, 04870 St Michel l’Observatoire, France
LUTH, Observatoire de Paris, CNRS and Université Paris Diderot, 5 place Jules Janssen, F-92195 Meudon, France
Rheinisches Institut für Umweltforschung an der Universität zu Köln, Aachener Strasse 209, D-50931, Köln, Germany
Research and Scientific Support Department, ESTEC/ESA, PO Box 299, 2200 AG Noordwijk, The Netherlands
NASA Exoplanet Science Institute/Caltech, South Wilson Avenue, Mail Code 100-22, Pasadena, California 91125, USA
University of Vienna, Institute of Astronomy, Türkenschanzstrasse 17, A-1180 Vienna, Austria
Institute of Astronomy, Geophysics and Atmospheric Sciences, Universidade de São Paulo, Brasil
Thüringer Landessternwarte, Sternwarte 5, D-07778 Tautenburg, Germany
University of Liège, Allée du 6 août 17, Sart Tilman, Liège 1, Belgium
Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Santa Barbara, California 93117, USA
Sydney Institute for Astronomy, School of Physics, The University of Sydney, New South Wales 2006, Australia
Space Research Institute, Austrian Academy of Science, Schmiedlstrasse 6, A-8042 Graz, Austria
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
Present addresses: European Southern Observatory Chile, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile (P.K.); Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile (M.R.).
Correspondence to: H. J. Deeg1,2 Correspondence and requests for materials should be addressed to H.J.D. (Email: hdeeg@iac.es).
Of the over 400 known1 exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets2, including the first terrestrial exoplanet3, 4(CoRoT-7b), have been discovered using a space mission5 designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274 days on a low eccentricity of 0.11 ± 0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a ‘temperate’ photospheric temperature estimated to be between 250 and 430 K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models6 with an inferred interior composition consistent with that of Jupiter and Saturn.
H. J. Deeg1,2, C. Moutou3, A. Erikson4, Sz. Csizmadia4, B. Tingley1,2, P. Barge3, H. Bruntt5, M. Havel6, S. Aigrain7,8, J. M. Almenara1,2, R. Alonso9, M. Auvergne5, A. Baglin5, M. Barbieri3,10, W. Benz11, A. S. Bonomo3, P. Bordé12, F. Bouchy13,14, J. Cabrera4,15, L. Carone16, S. Carpano17, D. Ciardi18, M. Deleuil3, R. Dvorak19, S. Ferraz-Mello20, M. Fridlund17, D. Gandolfi21, J.-C. Gazzano3, M. Gillon22, P. Gondoin17, E. Guenther21, T. Guillot6, R. den Hartog17, A. Hatzes21, M. Hidas23,24, G. Hébrard13, L. Jorda3, P. Kabath4,28, H. Lammer25, A. Léger12, T. Lister23, A. Llebaria3, C. Lovis9, M. Mayor9, T. Mazeh26, M. Ollivier12, M. Pätzold16, F. Pepe9, F. Pont7, D. Queloz9, M. Rabus1,2,28, H. Rauer4,27, D. Rouan5, B. Samuel12, J. Schneider15, A. Shporer26, B. Stecklum21, R. Street23, S. Udry9, J. Weingrill25 & G. Wuchterl21
Instituto de Astrofísica de Canarias, C. Via Lactea S/N, E-38205 La Laguna, Tenerife, Spain
Department de Astrofísica, Universidad de La Laguna, E-38200 La Laguna, Tenerife, Spain
Laboratoire d’Astrophysique de Marseille, CNRS and Université de Provence, 38 rue Frédéric Joliot-Curie, F-13388 Marseille cedex 13, France
Institute of Planetary Research, German Aerospace Center, Rutherfordstrasse 2, D-12489 Berlin, Germany
LESIA, Observatoire de Paris, CNRS, Place J. Janssen, 92195 Meudon cedex, France
Université de Nice-Sophia Antipolis, Observatoire de la Côte d'Azur, CNRS UMR 6202, 06304 Nice cedex 4, France
School of Physics, University of Exeter, Exeter, EX4 4QL, UK
Oxford Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH, UK
Observatoire de l’Université de Genève, 51 chemin des Maillettes, CH 1290 Sauverny, Switzerland
Dipartimento di Astronomia, Università di Padova, 35122 Padova, Italy
Universität Bern, Physics Institute, Sidlerstrasse 5, CH 3012 Bern, Switzerland
Institut d’Astrophysique Spatiale, Université Paris XI, F-91405 Orsay, France
IAP, 98bis boulevard Arago, F-75014 Paris, France
Observatoire de Haute-Provence, CNRS/OAMP, 04870 St Michel l’Observatoire, France
LUTH, Observatoire de Paris, CNRS and Université Paris Diderot, 5 place Jules Janssen, F-92195 Meudon, France
Rheinisches Institut für Umweltforschung an der Universität zu Köln, Aachener Strasse 209, D-50931, Köln, Germany
Research and Scientific Support Department, ESTEC/ESA, PO Box 299, 2200 AG Noordwijk, The Netherlands
NASA Exoplanet Science Institute/Caltech, South Wilson Avenue, Mail Code 100-22, Pasadena, California 91125, USA
University of Vienna, Institute of Astronomy, Türkenschanzstrasse 17, A-1180 Vienna, Austria
Institute of Astronomy, Geophysics and Atmospheric Sciences, Universidade de São Paulo, Brasil
Thüringer Landessternwarte, Sternwarte 5, D-07778 Tautenburg, Germany
University of Liège, Allée du 6 août 17, Sart Tilman, Liège 1, Belgium
Las Cumbres Observatory Global Telescope Network, Inc., 6740 Cortona Drive, Suite 102, Santa Barbara, California 93117, USA
Sydney Institute for Astronomy, School of Physics, The University of Sydney, New South Wales 2006, Australia
Space Research Institute, Austrian Academy of Science, Schmiedlstrasse 6, A-8042 Graz, Austria
School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany
Present addresses: European Southern Observatory Chile, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile (P.K.); Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile (M.R.).
Correspondence to: H. J. Deeg1,2 Correspondence and requests for materials should be addressed to H.J.D. (Email: hdeeg@iac.es).
Of the over 400 known1 exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets2, including the first terrestrial exoplanet3, 4(CoRoT-7b), have been discovered using a space mission5 designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period of 95.274 days on a low eccentricity of 0.11 ± 0.04 around a solar-like star. Its periastron distance of 0.36 astronomical units is by far the largest of all transiting planets, yielding a ‘temperate’ photospheric temperature estimated to be between 250 and 430 K. Unlike previously known transiting planets, the present size of CoRoT-9b should not have been affected by tidal heat dissipation processes. Indeed, the planet is found to be well described by standard evolution models6 with an inferred interior composition consistent with that of Jupiter and Saturn.
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