Sensitivity of Solar g-Modes to Varying G Cosmologies
Abstract
The sensitivity of the solar g-mode oscillation spectrum to variability in the universal gravitational constant G is described. Solar models in varying G cosmologies were constructed by evolving a zero-age main-sequence stellar model to the Sun's current age, while allowing the value of G to change according to the power law G(t) proportional to t-beta, where Beta approximately equals delta G/GH and H is the Hubble constant. All solar models were constrained to the observed luminosity and radius at the current age of the Sun by adjusting the helium abundance and the mixing-length parameter of the models in the usual way for standard stellar models. Low-l g-mode oscillation periods were calculated for each of the models and compared to the claimed observation of the solar g-mode oscillation spectrum by Hill & Gu (1990). If one accepts Hill & Gu's claims, then within the uncertainties of the physics of the solar model calculation, our models rule out all but (delta G/GH) less than approximately 0.05. In other words, we conclude that G could not have varied by more than 2% over the past 4.5 Gyr, the lifetime of the present-day Sun. This result lends independent support to the validity of the standard solar model.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1995
- DOI:
- 10.1086/175680
- Bibcode:
- 1995ApJ...445..148G
- Keywords:
-
- Abundance;
- Cosmology;
- Gravitation Theory;
- Gravitational Constant;
- Solar Oscillations;
- Stellar Evolution;
- Variability;
- Gravitational Fields;
- Nuclear Reactions;
- Stellar Composition;
- Stellar Luminosity;
- Stellar Models;
- Stellar Temperature;
- Astrophysics;
- COSMOLOGY: THEORY;
- GRAVITATION;
- SUN: OSCILLATIONS