Sparsely-Observed Pulsating Red Giants in the AAVSO Observing Program

TL;DR

This study analyzes time-series data of 156 sparsely-observed pulsating red giants from the AAVSO, providing average periods and amplitudes, and discusses challenges in observing these complex variable stars.

Contribution

It offers the first detailed analysis of sparsely-observed pulsating red giants and highlights the need for improved observation strategies for these stars.

Findings

Average periods and amplitudes obtained for some stars

Many stars exhibit complex pulsation behaviors

Raises questions on optimal observation management

Abstract

This paper reports on time-series analysis of 156 pulsating red giants (21 SRa, 52 SRb, 33 SR, 50 Lb) in the AAVSO (American Association of Variable Star Observers) observing program for which there are no more than 150-250 observations in total. Some results were obtained for 68 of these stars: 17 SRa, 14 SRb, 20 SR, and 17 Lb. These results generally include only an average period and amplitude. Many, if not most of the stars are undoubtedly more complex; pulsating red giants are known to have wandering periods, variable amplitudes, and often multiple periods including "long secondary periods" of unknown origin. These results (or lack thereof) raise the question of how the AAVSO should best manage the observation of these and other sparsely-observed pulsating red giants.