The period change of the Cepheid Polaris suggests enhanced mass loss

Abstract

Polaris is one of the most observed stars in the night sky, with recorded observations spanning more than 200 years. From these observations, one can study the real-time evolution of Polaris via the secular rate of change of the pulsation period. However, the measurements of the rate of period change do not agree with predictions from state-of-the-art stellar evolution models. We show that this may imply that Polaris is currently losing mass at a rate of $\dot{M}\approx 10^{-6}{M}_{\odot }$ yr${}^{-1}$ based on the difference between modeled and observed rates of period change, consistent with pulsation-enhanced Cepheid mass loss. A relation between the rate of period change and mass loss has important implications for understanding stellar evolution and pulsation, and provides insight into the current Cepheid mass discrepancy.

5 pages, 4 figures, compiled using emulateapj, Accepted for publication in ApJ Letters. Fixed correction in title