Open AccessA new white dwarf constraint on the rate of change of the gravitational constant
Author(s) -
Biesiada Marek,
Malec Beata
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07677.x
Subject(s) - physics , white dwarf , astrophysics , gravitational constant , gravitational binding energy , gravitation , oscillation (cell signaling) , gravitational redshift , gravitational energy , constant (computer programming) , astronomy , gravitational wave , stars , genetics , biology , computer science , programming language
In this paper we derive a bound on the rate of change of the gravitational constant G based on observations of the pulsating white dwarf G117‐B15A. This star is a ZZ Ceti pulsator which has been extensively studied with astroseismological techniques for the last three decades. The most recent determination of for the 215.2‐s fundamental mode agrees very well with predictions of the best‐fitting theoretical model. The rate of change of the oscillation period can be explained by two effects: the cooling (dominant factor) and change of gravitational binding energy (residual gravitational contraction). Since the white dwarfs are pulsating in g‐modes, the frequencies of which are related to the Brunt–Väisälä frequency (explicitly dependent on G ), observational determination of the change of the period (more precisely the difference between the observed and calculated ) can be used to set an upper bound on the rate of change of G . In light of the current data concerning G117‐B15A we derive the following bound: . We also demonstrate that a varying gravitational constant G does not modify the cooling of white dwarfs in a significant way, at least at the luminosities where white dwarfs are pulsationally unstable.