Further evidence for a color gradient in M15

Abstract

view Abstract Citations (32) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Further Evidence for a Color Gradient in M15 Cederbloom, S. E. ; Moss, M. J. ; Cohn, H. N. ; Lugger, P. M. ; Bailyn, C. D. ; Grindlay, J. E. ; McClure, R. D. Abstract Using data obtained at the Canada-France-Hawaii Telescope (CFHT) in subarcsecond seeing color maps are constructed in B - V and H-alpha - R of the central regions of the globular cluster M15. Comparison in B - V of the region within 0.31 pc of the cluster center with a coadded sample taken from the surrounding region demonstrates a color gradient, in the sense that the central region is bluer than the surrounding region at a high level of statistical significance. Analysis of the H-alpha - R color map indicates that the central region is 'H-alpha deficient', i.e., has a stronger H-alpha absorption line on average than the coadded region. This result argues against the possibility that the excess blue light from the central region is due to cataclysmic variables. Instead, two possible causes of the color gradient are (1) it may be due to a centrally concentrated population of faint blue stars, possibly resulting from binary-single star interactions, and (2) it may result from a central deficit of low-mass main-sequence stars. Publication: The Astronomical Journal Pub Date: February 1992 DOI: 10.1086/116076 Bibcode: 1992AJ....103..480C Keywords: Globular Clusters; Star Distribution; Stellar Color; Stellar Evolution; Astronomical Photography; H Alpha Line; Seeing (Astronomy); Ubv Spectra; Astrophysics; GLOBULAR CLUSTERS: IDIVIDUAL: M15; STARS: FUNDAMENTAL PARAMETERS full text sources ADS | data products SIMBAD (4)