Deep CCD photometry in globular clusters. I - The main sequence of M4

Abstract

view Abstract Citations (83) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Deep CCD photometry in globular clusters. I. The main sequence of M 4. Richer, H. B. ; Fahlman, G. G. Abstract Color-magnitude and color-color diagrams have been constructed for a 4 x 3-arcmin field of the globular cluster M4, on the basis of deep UBV CCD images. The color-magnitude diagram indicates that the main sequence, down to almost 3 mag below the turnoff, has an intrinsic width no greater than + or 0.02 mag in (B-V), implying either that the variation in He abundance in these stars must be less than + or - 0.07, or that the fractional variation in metallicity is not larger than + or - 0.22. Field stars in the direction of the cluster yield E(B-V) of 0.37 + or - 0.06, while the best present metallicity estimate for M4 is -0.93 + or - 0.31. The corresponding isochrones from VandenBerg (1983) are found to be in excellent general agreement with the present data. Publication: The Astrophysical Journal Pub Date: February 1984 DOI: 10.1086/161688 Bibcode: 1984ApJ...277..227R Keywords: Abundance; Globular Clusters; Main Sequence Stars; Stellar Evolution; Stellar Spectrophotometry; Ubv Spectra; Charge Coupled Devices; Color-Color Diagram; Color-Magnitude Diagram; Distance; Interstellar Extinction; Metallicity; Stellar Color; Stellar Magnitude; Astronomy full text sources ADS | data products SIMBAD (9) Related Materials (7) Part 2: 1985ApJS...58..225F Part 3: 1986ApJ...304..273R Part 4: 1987ApJ...316..189R Part 5: 1988ApJ...325..218R Part 6: 1988ApJ...329..187R Part 7: 1989AJ.....98.1335S Part 8: 1989AJ.....98.2124H