Measuring frequency and period separations in red-giant stars using machine learning
Abstract
Asteroseismology is used to infer the interior physics of stars. The Kepler and TESS space missions have provided a vast data set of red-giant light curves, which may be used for asteroseismic analysis. These data sets are expected to significantly grow with future missions such as PLATO, and efficient methods are therefore required to analyze these data rapidly. Here, we describe a machine learning algorithm that identifies red giants from the raw oscillation spectra and captures p and mixed mode parameters from the red-giant power spectra. We report algorithmic inferences for large frequency separation ( ), frequency at maximum amplitude (max), and period separation ( ) for an ensemble of stars. In addition, we have discovered 25 new probable red giants among 151,000 Kepler long-cadence stellar-oscillation spectra analyzed by the method, among which four are binary candidates which appear to possess red-giant counterparts. To validate the results of this method, we selected 3,000 Kepler stars, at various evolutionary stages ranging from subgiants to red clumps, and compare inferences of , , and max with estimates obtained using other techniques. The power of the machine-learning algorithm lies in its speed: it is able to accurately extract seismic parameters from 1,000 spectra in 5 seconds on a modern computer (single core of the Intel Xeon Platinum 8280 CPU).