Deep Hubble Space Telescope WFPC2 photometry of NGC 288. I. Binary systems and blue stragglers

Michele Bellazzini, Flavio Fusi Pecci, Maria Messineo, Lorenzo Monaco, Robert T. Rood

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

85 Citas (Scopus)

Resumen

We present the first results of a deep WFPC2 photometric survey of the loose galactic globular cluster NGC 288. The fraction of binary systems is estimated from the color distribution of objects near the main sequence (MS) with a method analogous to that introduced by Rubenstein & Bailyn. We have unequivocally detected a significant population of binary systems with a radial distribution that has been significantly influenced by mass segregation. In the inner region of the cluster (r < 1rh ≃ 1.6rc) the binary fraction (fb) lies in the range 0.08-0.38 regardless of the assumed distribution of mass ratios, F(q). The most probable fb lies between 0.10 and 0.20 depending on the adopted F(q). On the other hand, in the outer region (r ≥ 1rh), fb must be less than 0.10, and the most likely value is 0.0, independently of the adopted F(q). The detected population of binaries is dominated by primordial systems. The specific frequency of blue stragglers (BSs) is exceptionally high, suggesting that the BS production mechanism via binary evolution can be very efficient. A large population of BSs is possible even in low-density environments if a sufficient reservoir of primordial binaries is available. The observed distribution of BSs in the color-magnitude diagram is not compatible with a rate of BS production that has been constant in time, if it is assumed that all the BSs are formed by the merging of two stars.

Idioma originalInglés
Páginas (desde-hasta)1509-1527
Número de páginas19
PublicaciónAstronomical Journal
Volumen123
N.º3 1755
DOI
EstadoPublicada - mar. 2002

Áreas temáticas de ASJC Scopus

  • Astronomía y astrofísica
  • Ciencias planetarias y espacial

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