AAVSO: American Association of Variable Star Observers

Studies of Pulsating Red Giants using AAVSO and ASAS-SN Data (Abstract)

Volume 47 number 2 (2019)

John R. Percy
Department of Astronomy and Astrophysics, and Dunlap Institute of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada; john.percy@utoronto.ca
Lucas Fenaux
Department of Astronomy and Astrophysics, and Dunlap Institute of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada; john.percy@utoronto.ca

Abstract

(Abstract only) We review a decade of analysis and interpretation of AAVSO data on pulsating red giant stars (PRGs), with emphasis on several unexplained long-term phenomena which have been discovered using many decades of AAVSO visual observations. More recently, we have explored the use of data from the All-Sky Automated Survey for Supernovae (ASAS-SN), which provides over 2,000 days of sustained observations of hundreds of thousands of variables. ASAS-SN has used automated methods to analyze and classify variable stars. By examining two small samples of PRGs, we show that many of the ASAS-SN analyses and classifications of these types of variables are problematic for various reasons; we will show specific examples. We are now using ASAS-SN data to investigate the nature of semi-regular and irregular PRGs on the AAVSO visual program which are sparsely-observed and therefore poorly-understood. Both the AAVSO and ASAS-SN data, along with the AAVSO time-series software package vstar, are ideally suited for student projects at the senior secondary and post-secondary levels.