دورية أكاديمية
On the Radial Distribution of Horizontal Branch Stars in NGC 2808
| العنوان: | On the Radial Distribution of Horizontal Branch Stars in NGC 2808 |
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| المؤلفون: | Scilla Degl'Innocenti, L. Pulone, Annalisa Calamida, M. Zoccali, M. Monelli, P. B. Stetson, I. Ferraro, P. G. Prada Moroni, C. E. Corsi, Giuseppe Bono, Adriano Pietrinferni, G. Iannicola, R. Buonanno, Mario Nonino, Alistair R. Walker, Marco Castellani, A. Di Cecco, Massimo Dall'Ora, Martino Romaniello, Nicoletta Sanna, Filippina Caputo |
| سنة النشر: | 2009 |
| المجموعة: | Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
| مصطلحات موضوعية: | NEANIAS Space Research Community, Space and Planetary Science, Astronomy and Astrophysics |
| الوصف: | We present accurate new ultraviolet and optical BVI photometry for the Galactic globular cluster NGC 2808 based on both ground-based and archival Hubble Space telescope imagery. From this we have selected a sample of {approx}2000 Horizontal Branch (HB) stars; given the extensive wavelength range considered and the combination of both high angular resolution and wide-field photometric coverage, our sample should be minimally biased. We divide the HB stars into three radial bins and find that the relative fractions of cool, hot, and extreme HB stars do not change radically when moving from the center to the outskirts of the cluster: the difference is typically smaller than {approx}2{sigma}. These results argue against the presence of strong radial differentiation among any stellar subpopulations having distinctly different helium abundances. The ratio between HB and red giant (RG) stars brighter than the ZAHB steadily increases when moving from the innermost to the outermost cluster regions. The difference is larger than {approx}4{sigma} and indicates a deficiency of bright RGs in the outskirts of the cluster. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | unknown |
| العلاقة: | url:https://www.openaccessrepository.it/communities/itmirrorTest; https://www.openaccessrepository.it/record/99345Test |
| DOI: | 10.1088/0004-637x/696/2/l120 |
| الإتاحة: | https://doi.org/10.1088/0004-637x/696/2/l120Test https://www.openaccessrepository.it/record/99345Test |
| حقوق: | info:eu-repo/semantics/openAccess |
| رقم الانضمام: | edsbas.EDDB5C73 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1088/0004-637x/696/2/l120 |
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