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Centro de Astrofísica da Universidade do Porto

Determination of Masses and Ages of Kepler Targets from Model Fitting

A. L. Soares, M. S. Cunha

Abstract.
This poster analyses the determination of masses and ages of a selection of stars from the Kepler survey, by fitting some of their observables - namely, luminosity, metallicity, and effective temperature - to those derived from models of the Padova Stellar Evolutionary Tracks and Isochrones. The luminosity and its uncertainty are obtained through the parallax and V magnitude of the stars and respective errors.
For each star we perform Monte Carlo simulations of the 3 observables, assuming Gaussian distributions of the errors, and then use the chi square statistic to do the fit to the models. For each simulation we obtain the mass and age of the model that best fits the (simulated) observables - the one that minimizes the chi square - so that in the end each star has a distribution of mass and age. When those distributions are proved to be Gaussian, we can also determine the respective uncertainties.
The ages and masses resulting from this method will be compared (when possible) to those obtained by an asteroseismic analysis of data obtained with Kepler.

Third Kepler Asteroseismology Workshop: 'Kepler Asteroseismology in Action'
Aarhus, Denmark
June 2010

Type: Poster

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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