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WFPC2 observations of the globular cluster M30

1994; IOP Publishing; Volume: 435; Linguagem: Inglês

10.1086/187594

1538-4357

B. Yanny, Puragra Guhathakurta, Donald P. Schneider, John N. Bachall,

Astrophysics and Star Formation Studies

view Abstract Citations (40) References (19) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS WFPC2 Observations of the Globular Cluster M30 Yanny, Brian ; Guhathakurta, Puragra ; Schneider, Donald P. ; Bahcall, John N. Abstract We describe images of the center of the dense globular cluster M30 (NGC 7099) obtained with the Hubble Space Telescope Wide Field/Planetary Camera 2 (HST WFPC2). Data taken in the F336W, F439W, and F555W filters (approximately U, B, and V) yield a color-magnitude diagram with photometric errors of 1 sigma = 0.05 mag for stars with V less than 17.5, and 1 sigma approximately 0.1 mag at V = 20, which is 1.5 mag fainter than the main-sequence turnoff. Simulations show that the star identifications are essentially complete for stars with V less than 19.5, even in the densest regions of the cluster. The projected radial distribution of stars can be represented by a power law distribution: N(r) approximately ralpha, with slope alpha = -0.4 +/- 0.15, into radii less than 0.4 sec (0.015 pc). The radial profile is also consistent with a flat core of any radius smaller than approximately 1.5 sec (0.05 pc), but inconsistent with any core radius larger than 2.5 sec (0.09 pc). A total of 30 blue straggler candidates within 20 sec of the cluster center have been identified from the three-color data. Their radial distribution is strongly centrally concentrated when compared to the horizontal branch, red giant branch, or main-sequence stars in the cluster. The abundance of blue stragglers (relative to red giants and subgiants) within r approximately less than 20 sec of the center of M30 is fBS = 0.19 =/- 0.04, about twice as high as in other dense clusters. Publication: The Astrophysical Journal Pub Date: November 1994 DOI: 10.1086/187594 Bibcode: 1994ApJ...435L..59Y Keywords: Blue Stars; Globular Clusters; Radial Distribution; Color-Magnitude Diagram; Computerized Simulation; Hubble Space Telescope; Power Series; Stellar Luminosity; Astronomy full text sources ADS | data products SIMBAD (2) MAST (1) ESA (1)