Advancing Machine Learning for Stellar Activity and Exoplanet Period Rotation

TL;DR

This paper demonstrates that ensemble machine learning models can accurately estimate stellar rotation periods from Kepler light curve data, outperforming traditional methods and improving astrophysical analysis of stars and exoplanets.

Contribution

The study introduces a machine learning workflow using ensemble methods to improve the accuracy of stellar rotation period estimation from light curves.

Findings

Voting Ensemble achieved the lowest RMSE, about 50% lower than Decision Tree.

Random Forest performed comparably to the Voting Ensemble, indicating high accuracy.

Gradient Boosting showed worse performance compared to other models.

Abstract

This study applied machine learning models to estimate stellar rotation periods from corrected light curve data obtained by the NASA Kepler mission. Traditional methods often struggle to estimate rotation periods accurately due to noise and variability in the light curve data. The workflow involved using initial period estimates from the LS-Periodogram and Transit Least Squares techniques, followed by splitting the data into training, validation, and testing sets. We employed several machine learning algorithms, including Decision Tree, Random Forest, K-Nearest Neighbors, and Gradient Boosting, and also utilized a Voting Ensemble approach to improve prediction accuracy and robustness. The analysis included data from multiple Kepler IDs, providing detailed metrics on orbital periods and planet radii. Performance evaluation showed that the Voting Ensemble model yielded the most accurate results, with an RMSE approximately 50\% lower than the Decision Tree model and 17\% better than the K-Nearest Neighbors model. The Random Forest model performed comparably to the Voting Ensemble, indicating high accuracy. In contrast, the Gradient Boosting model exhibited a worse RMSE compared to the other approaches. Comparisons of the predicted rotation periods to the photometric reference periods showed close alignment, suggesting the machine learning models achieved high prediction accuracy. The results indicate that machine learning, particularly ensemble methods, can effectively solve the problem of accurately estimating stellar rotation periods, with significant implications for advancing the study of exoplanets and stellar astrophysics.