MG13 - Talk detail |
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Participant |
Garcia-Berro, Enrique | |||||||
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Institution |
Universitat Politècnica de Catalunya - c/Esteve Terrades 5 - Castelldefels - - Spain | |||||||
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Session |
EG2 |
Accepted |
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Order |
Time |
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Talk |
Oral abstract |
Title |
An upper limit to the variation of G from the white dwarf cooling sequence of NGC 6791 | |||||
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Abstract |
A variation of the gravitational constant over cosmological ages modifies the main sequence lifetimes and white dwarf cooling ages. Using an state-of-the-art stellar evolutionary code we compute the effects of a secularly varying $G$ on the main sequence ages and, employing white dwarf cooling ages computed taking into account the effects of a running $G$, we place constraints on the rate of variation of Newton's constant. This is done using the white dwarf luminosity function and the distance of the well studied open Galactic cluster NGC 6791. We derive an upper bound for the secular variation of the gravitational constant which compares favorably with those obtained using other stellar evolutionary properties, and can be easily improved if deep images of the cluster allow to obtain an improved white dwarf luminosity function. |
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