New Variable Stars in NGC 6652 and Its Background Sagittarius Stream∗ ∗ Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência,

• Published in: The Astronomical journal Vol. 157; no. 2
• Main Authors: Salinas, Ricardo, Vivas, A. Katherina, Ramos, Rodrigo Contreras
• Format: Journal Article
• Language: English
• Published: The American Astronomical Society 14.01.2019
• Subjects: galaxies: individual (Sgr dSph); globular clusters: individual (NGC 6652); stars: variables: delta Scuti; stars: variables: RR Lyrae
• ISSN: 0004-6256; 1538-3881
• DOI: 10.3847/1538-3881/aaf796

We conducted a variable star search on the metal-rich Galactic globular cluster NGC 6652 using archival Gemini-S/Gemini Multiobject Spectrograph data. We report the discovery of nine new variable stars in the NGC 6652 field, of which we classify six as eclipsing binaries and one as an SX Phoenicis star, leaving two variables without classification. Using proper motions from Gaia DR2 and Hubble Space Telescope, albeit with some uncertainties, we find that the cluster, the field, and the background Sagittarius stream each have three of these variables. We also reassess the membership of known variables based on the Gaia proper motions, confirming the existence of one RR Lyrae star in the cluster.