Title: SNIa, white dwarfs and the variation of the gravitational constant.
Abstract: White dwarfs represent the last evolutionary stage of stars with masses smaller than 10 ± 2 M . Since their mechanical structure is sustained by the pressure of degenerate electrons, they do not radiate nuclear energy and their evolution is just a simple gravothermal process of cooling. The only exception to this is the case of white dwarfs in close binary systems where, by accretion of matter from the companion, they can reach the Chandrasekhar’s mass and explode as a Type Ia supernova (SNIa). The cooling of single white dwarfs and the properties of SNIa strongly depend on the precise value of G and on its possible secular variation. Consequently, white dwarfs can be used to constrain such hypothetical variations. Although the bounds obtained in this way have been currently superseeded by other more accurate methods, when the ongoing surveys searching for SNIa and white dwarfs will be completed, the expected bounds will be as tight as ∼ 10−13 yr−1.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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