Periods and classifications of RR Lyrae stars in the globular cluster M15. Issue 1 (7th January 2021)

• Record Type: Journal Article
• Authors: Hoffman, Andrew M; Murakami, Yukei S; Zheng, WeiKang; Stahl, Benjamin E; Filippenko, Alexei V
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 502:Issue 1(2021)
• Page Start: 818
• Page End: 835
• Publication Date: 2021-01-07
• Subjects: methods: data analysis -- techniques: photometric -- stars: evolution -- stars: variables: RR Lyrae -- globular clusters: individual: M15; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab010
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present measurements of the periods, amplitudes, and types of 74 RR Lyrae stars in the globular cluster M15 derived from Nickel 1 m telescope observations conducted at Lick Observatory in 2019 and 2020. Of these RR Lyrae stars, two were previously reported but without a determination of the period. In addition, we identify five Type II Cepheid variable stars for which we report three novel period determinations, and a further 34 stars with uncertain classifications and periods. We discuss the development and subsequent application to our data of a new python package, Period-determination and Identification Pipeline Suite (pips ), based on a new adaptive free-form fitting technique to detect the periods of variable stars with a clear treatment of uncertainties.