A new age calibrator for red horizontal branch populations
نویسندگان
چکیده
منابع مشابه
The Age Dependent Luminosities of the Red Giant Branch Bump, Asymptotic Giant Branch Bump, and Horizontal Branch Red Clump
Color-magnitude diagrams of globular clusters often exhibit a prominent horizontal branch (HB) and may also show features such as the red giant branch (RGB) bump and the asymptotic giant branch (AGB) bump. Stellar evolution theory predicts that the luminosities of these features will depend on the metallicity and age of the cluster. We calculate theoretical lines of 2 to 12 Gyr constant age RGB...
متن کاملHorizontal-Branch Morphology as an Age Indicator
We present our recent revision of model constructions for the horizontal-branch (HB) morphology of globular clusters, which suggests the HB morphology is more sensitive to age compared to our earlier models. We also present our high precision CCD photometry for the classic second parameter pair M3 and M13. The relative age dating based on this photometry indicates that M13 is indeed older than ...
متن کاملRotation Velocities of Red and Blue Field Horizontal-Branch Stars
We present measurements of the projected stellar rotation velocities (v sin i) of a sample of 45 candidate field horizontal-branch (HB) stars spanning a wide range of effective temperature, from red HB stars with Teff ' 5000 K to blue HB stars with Teff of 17000 K. Among the cooler blue HB stars (Teff = 7500– 11500 K), we confirm prior studies showing that although a majority of stars rotate at...
متن کاملBlue Horizontal-Branch Stars and Simple Stellar Populations
The effects of blue horizontal-branch (HB) stars on the integrated spectrophotometric indices of simple stellar populations (SSPs) are addressed. Synthetic spectra are drawn from a grid of simulated globular clusters, constructed so as to reproduce the observed range of HB morphologies in the Milky Way system. Our models indicate that the Hβ line index increases by as much as 0.75 Å and the int...
متن کاملLine Broadening in Field Metal-poor Red Giant and Red Horizontal Branch Stars
We report 349 radial velocities for 45 metal-poor field red giant and red horizontal branch stars, with time coverage ranging from 1 to 21 years. We have identified one new spectroscopic binary, HD 4306, and one possible such system, HD 184711. We also report 57 radial velocities for 11 of the 91 stars reported on previously by Carney et al. (2003). All but one of the 11 stars had been found to...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1991
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/251.4.545