Infrared variable stars in the compact elliptical galaxy M32. Issue 1 (5th April 2021)

• Record Type: Journal Article
• Authors: Jones, O C; Nally, C; Sharp, M J; McDonald, I; Boyer, M L; Meixner, M; Kemper, F; Ferguson, A M N; Goldman, S R; Rich, R M
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 504:Issue 1(2021)
• Page Start: 565
• Page End: 575
• Publication Date: 2021-04-05
• Subjects: stars: late-type -- galaxies: individual (M32) -- galaxies: stellar content -- infrared: galaxies -- infrared: stars; stars: AGB and post-AGB; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab923
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: Variable stars in the compact elliptical galaxy M32 are identified, using three epochs of photometry from the Spitzer Space Telescope at 3.6 and 4.5 μ m, separated by 32 to 381 d. We present a high-fidelity catalogue of sources detected in multiple epochs at both 3.6 and 4.5 μ m, which we analysed for stellar variability using a joint probability error-weighted flux difference. Of these, 83 stars are identified as candidate large-amplitude, long-period variables, with 28 considered high-confidence variables. The majority of the variable stars are classified as asymptotic giant branch star candidates using colour-magnitude diagrams. We find no evidence supporting a younger, infrared-bright stellar population in our M32 field.