@MastersThesis{Carlos:2015:AnQuDi,
author = "Carlos, Mar{\'{\i}}lia Gabriela Cardoso Corr{\^e}a",
title = "An{\'a}lise qu{\'{\i}}mica diferencial detalhada de estrelas de
tipo solar pobres em metais com e sem planetas",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2015",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2015-04-14",
keywords = "estrelas, estrelas abund{\^a}ncias, an{\'a}lise
espectrosc{\'o}pica, planetas extrassolares, gal{\'a}xia disco,
stars, stars abundances, spectroscopic analysis, extrasolar
planets, galaxy disk.",
abstract = "Este projeto {\'e} focado no estudo de estrelas de tipo solar
moderadamente pobres em metais, com e sem planetas, para a
investiga{\c{c}}{\~a}o da exist{\^e}ncia (ou n{\~a}o) de uma
conex{\~a}o entre anomalias na composi{\c{c}}{\~a}o
qu{\'{\i}}mica e a presen{\c{c}}a de planetas. Analisou-se
espectros de alta resolu{\c{c}}{\~a}o e raz{\~a}o
sinal-ru{\'{\i}}do (R=65.000, > 300, espectrografo MIKE,
telesc{\'o}pio Magellan, Las Campanas Observatory, Chile) a fim
de se derivar diferen{\c{c}}as de abund{\^a}ncias com
alt{\'{\i}}ssima precis{\~a}o para elementos vol{\'a}teis e
refrat{\'a}rios (erros entre 0,01 e 0,05 dex). A metodologia
{\'e} baseada na an{\'a}lise espectrosc{\'o}pica diferencial,
que tamb{\'e}m fornece diferen{\c{c}}as precisas em temperatura
efetiva (\$T_{ef}\$), gravidade superficial (log g) e
metalicidade ([Fe/H]) para diversos pares de estrelas parecidas em
temperatura e metalicidade. Distinguimos estrelas do disco fino
daquelas do disco espesso e as dividimos em grupos
{"}homog{\^e}neos{"} em Tef e [Fe/H]. Para se obter as
diferen{\c{c}}as em Tef, log g e [X/H] aplicamos o m{\'e}todo de
largura equivalente aplicado a linhas do FeI e FeII com o
aux{\'{\i}}lio do pacote IRAF e o c{\'o}digo MOOG, que resolve
o transporte radiativo fotosf{\'e}rico considerando
equil{\'{\i}}brio termodin{\^a}mico local. No caso do carbono a
regi{\~a}o molecular \$C_{2}\$(0,0)\$\lambda\$5165A foi
analisada por meio de s{\'{\i}}ntese espectral (via MOOG
tamb{\'e}m). O nitrog{\^e}nio teve sua abund{\^a}ncia
qu{\'{\i}}mica calculada via s{\'{\i}}ntese espectral das
linhas 3882,52 A e 3882,70 A da banda (0,0) do sistema B-X Violeta
do CN. Tamb{\'e}m verificou-se se h{\'a} alguma
rela{\c{c}}{\~a}o entre as abund{\^a}ncias elementais
diferenciais e suas temperaturas de condensa{\c{c}}{\~a}o de
poeira por entre pares de estrelas similares. Foram estudadas 23
estrelas, com resultados obtidos para 17 pares de estrelas. Quatro
pares apresentaram resultados promissores que sugerem a
defici{\^e}ncia de elementos refrat{\'a}rios em
rela{\c{c}}{\~a}o a elementos vol{\'a}teis nas camadas mais
externas das estrelas. Tr{\^e}s pares tiveram seus resultados
descartados devido {\`a} incompatibilidade de par{\^a}metros
fotosf{\'e}ricos entre as estrelas da an{\'a}lise diferencial e
os outros pares devem ter a an{\'a}lise revista. ABSTRACT: The
present project aims to study moderately metal-poor solar-type
stars, with and without planets, to investigate the existence (or
not) of a connection between abnormalities in the chemical
composition of stars and the presence of planets. We analysed high
resolution spectra with high signal to noise ratio (R = 65.000, S/
N > 300, MIKE spectrograph, Magellan Telescope, Las Campanas
Observatory, Chile) in order to derive high precision abundance
differences in volatile and refractory elements, with errors
between 0,01 and 0,05 dex. The methodology is based on
differential spectroscopic analysis, which also provides precise
differences in temperature (\$T_{teff}\$) ,surface gravity (log
g) and metallicity ([Fe/H]), for several pairs of stars similar in
temperature and metallicity, The stars were distinguished in those
which belongs to the thin or thick disk, and then divided into
\${{"}}\$homogeneous\${{"}}\$ groups of \$T_{teff}\$ and
[Fe/H]. In order to obtain the differences in \$T_{teff}\$, log
g and [X/H] we applied the equivalent width method with the IRAF
package and the MOOG code, which solves the photospheric radiative
transfer assuming local thermodynamic equilibrium. In the case of
carbon the molecular region \$C_{2}\$(0,0)\$\lambda\$5165A
was analysed through spectral synthesis (via MOOG). For the
nitrogen, we analysed the lines 3882,52 A and 3882,70 A in the
molecular region of the violet CN B-X system through spectral
synthesis as well. We als o verified whether there is any relation
between the differential elemental abundances and the dust
condensation temperatures among pairs of similar stars. In total,
23 stars have been studied with results to 17 pairs of them.
Amongst all these pairs, 4 showed promising results which
confirmed the refractory elemental depletion in the external
layers of stars. The result of three pairs are dis-carded since
the derived photospheric parameters have no compatibility with
their groups, the others pairs should be analysed again.",
committee = "Rodrigues, Cl{\'a}udia Vilega (presidente) and Milone, Andr{\'e}
de Castro (orientador) and Moreno, Jorge Luis Melendez
(orientador) and Valio, Adriana Benetti Marques and Rossi, Silvia
Cristina Fernandes",
copyholder = "SID/SCD",
englishtitle = "Detailed diferential chemical analisys of sun-like metal poor
stars with or without planets",
language = "pt",
pages = "120",
ibi = "8JMKD3MGP3W34P/3J7RUPS",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3J7RUPS",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}