Dust is forming along the red giant branch of 47 TUC

Abstract

We present additional evidence that dust is really forming along the red giant branch (RGB) of 47 Tuc at luminosities ranging from above the horizontal branch to the RGB-tip (Origlia et al. 2007). The presence of dust had been inferred from an infrared excess in the (K-8) color, with K measured from high spatial resolution ground based near-IR photometry and "8" referring to Spitzer-IRAC 8 micron photometry. We show how (K-8) is a far more sensitive diagnostic for detecting tiny circumstellar envelopes around warm giants than colors using only the Spitzer-IRAC bands, for example the (3.6-8) color used by Boyer et al. (2010). In addition, we also show high resolution HST-ACS I band images of the giant stars which have (K-8) color excess. These images clearly demonstrate that Boyer et al (2010) statement that our detections of color excess associated with stars below the RGB-tip arise from blends and artefacts is simply not valid.

12 pages, 4 figures

References in corpus (3)

• The First Empirical Mass Loss Law for Population II Giants
• A Spitzer Space Telescope Atlas of omega Centauri: The Stellar Population, Mass Loss, and the Intracluster Medium
• Mass Outflow from Red Giant Stars in M13, M15, and M92

Cited by in corpus (20)

• Asteroseismology of old open clusters with Kepler: direct estimate of the integrated RGB mass loss in NGC6791 and NGC6819
• Reconstructing the stellar mass distributions of galaxies using S4G IRAC 3.6 and 4.5 micron images: II. The conversion from light to mass
• Production of dust by massive stars at high redshift
• Fundamental parameters, integrated RGB mass loss and dust production in the Galactic globular cluster 47 Tucanae
• On the red giant branch mass loss in 47 Tucanae: Constraints from the horizontal branch morphology
• Integrated Mass Loss of Evolved Stars in M4 using Asteroseismology
• An empirical mass-loss law for Population II giants from the Spitzer-IRAC survey of Galactic globular clusters
• Weighing stars: the identification of an Evolved Blue Straggler Star in the globular cluster 47 Tucanae
• The VISIR@VLT Mid-IR view of 47Tuc: A further step in solving the puzzle of RGB mass loss
• ALMA reveals sunburn: CO dissociation around AGB stars in the globular cluster 47 Tucanae
• Modelling chromospheric line profiles as diagnostics of velocity fields in ω Centauri red giant stars
• Formation and Evolution of Blue Stragglers in 47 Tucanae
• Spatially resolving the outer atmosphere of the M giant BK Vir in the CO first overtone lines with VLTI/AMBER
• VISTA's view of the Sagittarius dwarf spheroidal galaxy and southern Galactic Bulge
• Dynamical estimate of post main sequence stellar masses in 47 Tucanae
• A CO-multilayer outer atmosphere for eight evolved stars revealed with VLTI/AMBER
• Stellar-Encounter Driven Red-Giant Star Mass-Loss in Globular Clusters
• Chemical evolution of galaxies: emerging dust and the different gas phases in a new multiphase code
• Comparing Mid-Infrared Globular Cluster Colors With Population Synthesis Models
• HAYDN -- High-precision AsteroseismologY of DeNse stellar fields (ESA Voyage 2050 White Paper)