Rotation Velocities of Hot Horizontal Branch Stars in the Globular Clusters Ngc 1904, Ngc 2808, Ngc 6093, and Ngc 7078: the Database
نویسندگان
چکیده
We present radial and rotation (vsini) velocity measurements, from UVES+VLT high resolution spectra of 61 stars in the blue horizontal branches (HB) of the Galactic globular clusters NGC 1904 (M79), NGC 2808, NGC 6093 (M80), and NGC 7078 (M15). The data reduction and the velocity determination, based on cross-correlation techniques, are discussed in detail. Most of this database has been used by RecioBlanco et al. (2002) in their analysis of the rotation velocity properties of blue HB stars. Here we present additional data for NGC 2808. We confirm the results of the previous paper, in particular, a possible link between the HB jump and the abrupt change in the rotational velocity distribution around Teff ∼ 11,500 K.
منابع مشابه
Rotation of Hot Horizontal Branch Stars in Galactic Globular Clusters
We present high resolution UVES+VLT spectroscopic observations of 61 stars in the extended blue horizontal branches of the Galactic globular clusters NGC 1904 (M79), NGC 2808, NGC 6093 (M80), and NGC 7078 M15). Our data reveal for the first time the presence in NGC 1904 of a sizable population of fast (vsini ≥ 20 km/s) horizontal branch (HB) rotators, confined to the cool end of the EHB, simila...
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