Observational Constraints on Brans-Dicke Theory with a Variable Cosmological Term

We investigate Big-Bang nucleosynthesis in the Brans-Dicke model with a variable cosmological term (BDA) for the coupling constant ω=10^4. The model parameters are constrained from comparison between the resulting abundance of ^4He, D and ^7Li and the observed ones. Furthermore, we examine the magnitude redshift (m-z) relation for the BDA with and without another constant cosmological term in a flat universe. Observational data of Type Ia Supernovae (SNIa) are used in the redshift range 0.01<z<2. It is found that BDA is inconsistent with the present accelerating universe but the model with a constant cosmological term with the value 0.7 can explain the SNIa data. The model parameters are insensitive to the m-z relation

History of solar oblateness measurements and interpretation

International audienc