Another brick in understanding chemical and kinematical properties of BSSs: NGC 6752

Abstract

We used high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 22 Blue Straggler Stars (BSSs) and 26 red giant branch stars in the nearby globular cluster NGC 6752. We measured radial and rotational velocities and Fe, O and C abundances. According to radial velocities, metallicity and proper motions we identified 18 BSSs as likely cluster members. We found that all the BSSs rotate slowly (less than 40 km/s), similar to the findings in 47 Tucanae, NGC 6397 and M30. The Fe abundance analysis reveals the presence of 3 BSSs affected by radiative levitation (showing [Fe/H] significantly higher than that measured in "normal" cluster stars), confirming that element transport mechanisms occur in the photosphere of BSSs hotter than 8000 K. Finally, BSS C and O abundances are consistent with those measured in dwarf stars. No C and O depletion ascribable to mass transfer processes has been found on the atmospheres of the studied BSSs (at odds with previous results for 47 Tucanae and M30), suggesting the collisional origin for BSSs in NGC 6752 or that the CO-depletion is a transient phenomenon.

ApJ accepted

References in corpus (10)

• DAOSPEC: an automatic code for measuring equivalent widths in high-resolution stellar spectra
• Dynamical age differences among coeval star clusters as revealed by blue stragglers
• Dynamical Formation of Close Binaries in Globular Clusters II: Cataclysmic Variables
• Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process
• High Precision Differential Abundance Measurements in Globular Clusters: Chemical Inhomogeneities in NGC 6752
• Rotation and Macroturbulence in Metal-poor Field Red Giant and Red Horizontal Branch Stars
• FLAMES and XSHOOTER spectroscopy along the two BSS sequences of M30
• A Megacam Survey of Outer Halo Satellites. II. Blue Stragglers in the Lowest Stellar Density Systems
• New clues on the nature of the companion to PSR~J1740-5340 in NGC6397 from XSHOOTER spectroscopy
• An Overview of the Rotational Behavior of Metal--Poor Stars

Cited by in corpus (11)

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• Blue straggler masses from pulsation properties. II. Topology of the Instability Strip
• oMEGACat III. Multi-band photometry and metallicities reveal spatially well-mixed populations within $\omega$ Centauri's half-light radius
• Barium Surface Abundances of Blue Stragglers in the Open Cluster NGC 6819
• Spectroscopic and asteroseismic analysis of the remarkable main-sequence A star KIC 11145123
• SHOTGLAS II. MUSE spectroscopy of blue horizontal branch stars in the core of $\omega$ Centauri and NGC 6752
• Blue Straggler Stars in Globular Clusters: a powerful tool to probe the internal dynamical evolution of stellar systems
• Rotational velocities of Blue Straggler Stars in the Globular Cluster M55
• Fast Rotating Blue Straggler Stars in the globular cluster NGC 1851