A possible solution for the faint young Sun paradox: Clues from the exoplanetary data

TL;DR

This study proposes that higher early solar mass and additional planetary mass near the Sun could resolve the faint young Sun paradox, supported by empirical relationships derived from exoplanetary data.

Contribution

It introduces an empirical relationship between stellar mass loss rate, mass, and age, and applies it to estimate the Sun's early mass and nearby planetary mass, offering a potential solution to FYSP.

Findings

Early solar mass estimated at ~1.061 solar masses.

Planetary mass near Sun estimated at ~0.84 Jupiter masses.

Higher early solar mass could alleviate FYSP.

Abstract

Faint young Sun paradox (FYSP) is one of the unsolved problem in solar physics. The present study aims to get a possible solution for the FYSP through sun-like G stars and their exoplanetary systems. Using physical properties of exoplanetary data, an empirical relationship between the rate of mass loss ($\frac{dM}{dt}$) with stellar mass (M$_{\star}$) and age ({\em t}) is obtained. We found mass loss rate varies with stellar mass as $\propto$ $(M_{\star}/M_\odot)^{-3.788}$ and proportional to the age as $\propto$ t$^{-1.25}$, which indicates rate of mass loss is higher during early evolutionary stages. Then we applied mass loss corrections to stellar masses of G-type stars with planets and obtained their initial masses at the early evolutionary stages. Subsequently, we applied these relationships to calculate the mass loss rate and mass of Sun at the early evolutionary stage, which is found to be $\sim$ 10$^{-11}$ solar mass per year and $\sim$ (1.061$\pm$0.006) solar mass respectively. The higher solar mass can probably alleviate the problem of the faint young Sun paradox. Then the estimated initial stellar masses of the host stars are used to obtain a best power law relationship with the planetary masses that supports the hypothesis that the {\em massive stars harbour massive planets.} Finally, by using the same empirical power law, planetary mass in the vicinity of Sun is estimated to be $\sim$ (0.84$\pm$0.19) Jupiter mass, which is much higher compared to the present solar terrestrial planetary mass. Hence, this study also suggests that there is a missing planetary mass in the vicinity of the Sun, which can solve the FYSP problem.