Modeling of solar twins in M67

Matthieu Castro (Univ. Federal do Rio Grande do Norte)

M67 is a dense galactic star cluster rated at magnitude 6.9 and located nearly 1500 light-years above the plane of the Milky Way galaxy. The stars in the M67 cluster present an age of about 4 billion years, from dating method based only on the cooling rates of white dwarf stars. On this context we use the non-standard mixing history applied fo 10 well-studied solar twins of the open cluster M67 in order to determine as precisely as possible their mass and age. We computed a grid of evolutionary models with non-standard mixing at given metallicity with the Toulouse-Geneva code for a range of stellar masses. An interpolation code give us the evolutionary model that best fit the observed low lithium abundances for M67 twins. The result from this interpolation is a determination of mass and age of each star. Based on recent low resolution observations, our analysis can not draw a result as accurate as possible with this method.

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