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Análise Espectroscópica Detalhada De Estrelas Candidatas a Gêmeas

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Análise Espectroscópica Detalhada De Estrelas Candidatas a Gêmeas Universidade Federal do Rio de Janeiro Centro de Ci^enciasMatem¶aticase da Natureza Observat¶oriodo Valongo ANALISE¶ ESPECTROSCOPICA¶ DETALHADA DE ESTRELAS CANDIDATAS A GEMEAS^ SOLARES Leandro Di Bartolo 2005 UFRJ ANALISE¶ ESPECTROSCOPICA¶ DETALHADA DE ESTRELAS CANDIDATAS A GEMEAS^ SOLARES Leandro Di Bartolo Disserta»c~aode Mestrado apresentada ao Programa de P¶os-gradua»c~aoem Astronomia, Observat¶oriodo Valongo, da Universidade Federal do Rio de Janeiro, como parte dos requisitos necess¶arios`aobten»c~aodo t¶³tulode Mestre em Astronomia. Orientador: Gustavo Frederico Porto de Mello Rio de Janeiro Agosto de 2005 ii . Di Bartolo, Leandro An¶aliseEspectrosc¶opicaDetalhada de Estrelas Candidatas a G^emeasSolares / Leandro Di Bartolo. { UFRJ/OV, 2005. viii, 100f.: il; 29,7 cm. Orientador: Gustavo Frederico Porto de Mello Disserta»c~ao(mestrado) { UFRJ/OV/Programa de P¶os-gradua»c~aoem Astronomia, 2005. Refer^enciasBibliogr¶a¯cas:f. 82-84. 1. G^emeasSolares. 2. Abund^anciasQu¶³micas. 3. Estrelas Frias. I. Porto de Mello, Gustavo. II. Uni- versidade Federal do Rio de Janeiro, Observat¶oriodo Valongo, Programa de P¶os-gradua»c~aoem Astronomia. III. T¶³tulo. iii \Ora (direis) ouvir estrelas! Certo Perdeste o senso!"E eu vos direi, no entanto, Que, para ouvi-las muita vez desperto E abro as janelas, p¶alidode espanto... E conversamos toda noite, enquanto A Via L¶actea,como um p¶alioaberto, Cintila. E, ao vir o Sol, saudoso e em pranto, Inda as procuro pelo c¶eudeserto. Direis agora: \Tresloucado amigo! Que conversas com elas? Que sentido Tem o que dizes, quando n~aoest~aocontigo?" E eu vos direi: \Amai para entend^e-las! Pois s¶oquem ama pode ter ouvido Capaz de ouvir e de entender estrelas Olavo Bilac | 1888 iv AGRADECIMENTOS Agrade»coespecialmente ao meu orientador Gustavo Porto de Mello por ter me propiciado toda uma infra-estrutura que muito contribuiu para o sucesso deste trabalho, no tempo ex¶³guoatualmente exigido ao aluno de mestrado. Obrigado, tamb¶em,pela redu»c~aode parte dos espectros OPD/LNA utilizados neste trabalho e, ainda, por ter observado tais espectros e idealizado este projeto de pesquisa. Sou extremamente grato ao apoio prestado ao longo de todo o trabalho e, em especial, nos momentos mais dif¶³ceise em seu ¯nal. Estou certo de que a continua»c~aode minha forma»c~aocient¶³¯catendo como orientador o Gustavo ser¶a,uma vez mais, muito enriquecedora para mim n~aos¶ocomo pro¯ssional, mas tamb¶emcomo pessoa. Agrade»coa Licio da Silva por ter observado os espectros FEROS analisados neste trabalho, bem como pela corre»c~aodas velocidades radiais. Gostaria de agradecer tamb¶emao colega Eduardo del Peloso, meu ex-companheiro de sala, pela assist^enciadada em alguns dom¶³niosnovos para mim da inform¶atica,pelo apoio prestado em diversas partes deste trabalho e tamb¶empelas valiosas discuss~oesas- trof¶³sicasque muito contribu¶³rampara o meu aprendizado (calouro que era em astrof¶³sica ao ingressar no OV). Meus sinceros agradecimentos aos colegas da p¶os-gradua»c~aodo Valongo, que em- bora poucos s~aobons, por propiciarem um clima descontra¶³dot~aoagrad¶avel e prop¶³cio`a pesquisa. Todas as conversas de corredor que, em meio `acorreria do mestrado, inevit¶avel nos dias atuais, ajudam a arejar a cabe»cae ensejam a produtividade. Agrade»coem espe- cial a meus amigo Luis Juracy Lemos pela grande amizade que constru¶³mosem t~aopouco tempo e a Gustavo de Barros que, mesmo tendo sido meu calouro na UERJ, tornou-se amigo tamb¶emnestes tempos de p¶os. Agrade»coa voc^esdois por compartilharem bons momentos, seja nos bares, sambas, forr¶os,trilhas, praias, congressos da vida... Valeu amigos! Uma pessoa que eu gostaria de fazer um agradecimento especial ¶eao amigo e ex- orientador Jaime Rocha. Obrigado n~aos¶opor ter se colocado a disposi»c~aopara as re- vis~oesda tese, mas principalmente pela con¯an»cadepositada durante quase toda a minha forma»c~aopro¯ssional, desde os tempos no campus do MAST/ON e UERJ (como aluno e orientando de monogra¯a), at¶eo presente. Obrigado pela disponibilidade existencial e v pela cumplicidade ao longo de anos t~aoimportantes da minha vida. Obrigado tamb¶em ao amigo Fabr¶³cioCasarejos. Embora o tempo e as circunst^anciasnos tenham distanci- ado no ¶ultimoano, nos levando para caminhos diferentes, gostaria de registrar que sinto saudade das muitas e boas discuss~oespret¶eritassobre ¯loso¯a, ci^enciae a vida que muito me foram valiosas. Valeu amigos, voc^esestar~aosempre no cora»c~ao. Agrade»co`aminha namorada Denise Costa pelo apoio nas horas mais dif¶³ceis, pelo carinho e amor dedicados `aminha pessoa. Agrade»cotamb¶empelos bons momentos que compartilhamos juntos ao longo deste um ano de conviv^encia,que muito contribu¶³ram para a minha felicidade e, portanto, para o sucesso deste trabalho. Agrade»coao pessoal l¶ade casa, minha querida fam¶³lia,pelo apoio, carinho e assist^encia dados sem os quais a realiza»c~aodeste projeto teria sido simplesmente imposs¶³vel. Eu amo todos voc^es: minha m~aeDenise e minhas irm~asTamara e Priscila, minha querida av¶o Mar¶³liae o grande homem que foi meu av^o.Obrigado tamb¶emao meu querido pai. Agrade»coa todos os funcion¶ariosdo Observat¶oriodo Valongo e a UFRJ pela estrutura fornecida, em especial a Rosa e a Heloisa, por sempre terem se mostradas sol¶³citaspara o encaminhamento de quest~oesacad^emicase burocr¶aticas. Ao LNA/OPD e ao ESO Sul pelas estruturas, sem as quais, s~aoteria havido espectros para realiza»c~aodo presente trabalho. Agrade»coa CAPES pelo apoio prestado atrav¶esda bolsa. vi RESUMO ANALISE¶ ESPECTROSCOPICA¶ DETALHADA DE ESTRELAS CANDIDATAS A GEMEAS^ SOLARES Leandro Di Bartolo Orientador: Gustavo Frederico Porto de Mello Resumo da disserta»c~aode Mestrado submetida ao Programa de P¶os-gradua»c~aoem Astronomia, do Observat¶oriodo Valongo da Universidade Federal do Rio de Janeiro | OV/UFRJ, como parte dos requisitos necess¶ariosa obten»c~aodo t¶³tulo de Mestre em Astronomia. G^emeasSolares s~aode¯nidas como estrelas de mesma massa, idade, par^ametrosat- mosf¶ericos(temperatura, metalicidade e gravidade super¯cial), luminosidade, composi»c~ao qu¶³mica,estado evolutivo, atividade cromosf¶erica,deple»c~aodo Li, e demais caracter¶³sticas que o Sol. Tais objetos podem ajudar a responder `aquest~ao,ainda n~aointeiramente resolvida, de qu~aot¶³pico¶eo Sol com rela»c~ao`apopula»c~aolocal de estrelas tipo G de meia idade. Por outro lado, tais estrelas s~aopresumivelmente candidatas privilegiadas a possu¶³remsistemas planet¶ariossimilares ao nosso, sendo, ainda, locais naturais para se procurar planetas tel¶uricoshabitados por formas de vida semelhantes `anossa e, ainda, para realizar pesquisas do programa SETI. Identi¯cada HD146233 como a melhor g^emea j¶aencontrada em Porto de Mello & da Silva (1997), seguiu-se uma investiga»c~ao(da Silva (2000)) que encontrou diversas boas candidatas a g^emeassolares entre estrelas tipo G dentro de 50 parsecs de dist^ancia. Neste trabalho, n¶osinvestigamos detalhadamente as estrelas melhores candidatas a g^emease an¶alogasprovenientes desta investiga»c~ao. E¶ feita uma completa e detalhada an¶aliseespectrosc¶opicadestas estrelas, uniformemente baseada em espectros ESO/FEROS de alta resolu»c~ao(R = 47.000) e alta rela»c~aosinal/ru¶³do(S/R & 350). Determinamos suas temperaturas efetivas, abund^anciado Fe, gravidade super- ¯cial e velocidade de microturbul^enciapelo equil¶³briode excita»c~ao& ioniza»c~aode um grande n¶umerode linhas do Fe. Obtemos tamb¶ema temperatura efetiva baseada em calibra»c~oesfotom¶etricase ajustes te¶oricosdo per¯l de H®. Determinamos tamb¶emas abund^anciasde Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Y, Ba e Ce, al¶emdas componentes gal¶acticasdas velocidades estelares, da atividade cromosf¶ericapor meio de seu fluxo abso- luto em H® e em H & K do Ca II. Tamb¶emavaliamos qualitativamente suas abund^ancias vii de Li. Obtivemos tamb¶emsuas massas e idades em diagramas HR te¶oricos.Realizamos, ao ¯nal, uma an¶alisecompleta dos resultados em compara»c~aocom as propriedades do Sol, e encontramos diversas novas candidatas a g^emeassolares, discutindo em detalhes as suas propriedades. Palavras-chave: Estrelas: tipo solar, Estrelas: g^emeassolares; Estrelas: atividade cro- mosf¶erica;Estrelas: composi»c~aoqu¶³mica;Estrelas: par^ametrosatmosf¶ericos. Rio de Janeiro Agosto de 2005 viii ABSTRACT DETAILED SPECTROSCOPY ANALYSIS OF SOLAR TWIN CANDIDATE STARS Leandro Di Bartolo Orientador: Gustavo Frederico Porto de Mello Resumo da disserta»c~aode Mestrado submetida ao Programa de P¶os-gradua»c~aoem Astronomia, do Observat¶oriodo Valongo da Universidade Federal do Rio de Janeiro | OV/UFRJ, como parte dos requisitos necess¶ariosa obten»c~aodo t¶³tulo de Mestre em Astronomia. Solar twins are de¯ned as stars with the same mass, age, atmospheric parameters (temperature, metalicity, surface gravity) luminosity, chemical composition, evolutionary state, chromospheric activity, Li depletion, and other characteristics as the Sun. Such objects may help answer the still lingering question of how typical the Sun is with respect to the local stellar population of middle-aged G-type stars. On the other hand, such a stars are presumably privileged candidates to possess planetary systems similar to our own, besides being natural places to look for telluric planets harboring life forms similar to those known to us, and for the SETI program researches. Upon identi¯cation of HD146233 as the best ever solar twin (Porto de Mello & da Silva (1997)), a following survey (da Silva (2000)) identi¯ed a number of further candidates to solar twin status among the G-type stars within 50 parsecs of the Sun. In this work, we investigate the best solar twin and solar analog candidates proposed by this survey.
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