相关论文: The effect of diffusion on the Red Giant luminosit…

New theoretical evaluations of the RGB luminosity function 'bump' and the ZAHB luminosity covering the range of metallicities typical of galactic globular cluster are presented. The variation of the theoretical RGB bump and ZAHB levels due…

We present observational estimates of the magnitude difference between the luminosity function RGB bump and the HB (Delta(bump-zahb)), and of star counts in the bump region (R_bump), for a sample of 54 Galactic globular clusters (GCs)…

The Red-Giant Branch Bump (RGBB) is one of the most noteworthy features in the red-giant luminosity function of stellar clusters. It is caused by the passage of the hydrogen-burning shell through the composition discontinuity left at the…

We present new measurements of the magnitude of the main sequence turn off and the red giant branch bump in the luminosity function of a sample of Galactic globular clusters with updated estimates of [Fe/H] and [$\alpha$/Fe], employing…

V-band luminosity functions have been obtained for the upper main-sequence, sub-giant branch and red giant branch of 18 galactic globular clusters from HST data. A comparison with four sets of theoretical models has been performed. In…

We suggest to use the shape of the Red Giant Branch (RGB) Bump in metal-rich globular clusters as a diagnostic of partial mixing processes between the base of the convective envelope and the H-burning shell. The Bump located along the…

A Monte Carlo simulation exploring uncertainties in standard stellar evolution theory on the red giant branch of metal-poor globular clusters has been conducted. Confidence limits are derived on the absolute V-band magnitude of the bump in…

We introduce a new parameter {\Delta}{\xi} - the difference in magnitude between the red giant branch (RGB) bump and a point on the main sequence (MS) at the same color as the bump, the "benchmark" - to estimate the helium content in old…

We present new empirical calibrations of the Red Giant Branch (RGB) Bump and Tip based on a homogeneous near-Infrared database of 24 Galactic Globular Clusters. The luminosities of the RGB Bump and Tip in the J, H and K bands and their…

The increase in luminosity as a star evolves on the red-giant branch is interrupted briefly when the hydrogen-burning shell reaches the vicinity of the composition discontinuity left behind from the first convective dredge-up. The…

I report on the recent discoveries of the Red Giant Branch Bump(s) in many dwarf Spheroidal galaxies of the Local Group. The perspectives for the use of this new observational feature to obtain constraints on the Star Formation History and…

We present V and I photometry of a 9.4' X 9.4' field centered on the dwarf spheroidal galaxy Leo II. The Tip of the Red Giant Branch is identified at I^{TRGB}=17.83 +/- 0.03 and adopting <[M/H]> = -1.53 +/- 0.2 from the comparison of RGB…

The abundances of mixing--sensitive elements including lithium, [C/N], and 12C/13C are known to change near the red giant branch bump. The explanation most often offered for these alterations is double diffusive thermohaline mixing in the…

We measure the red giant branch bump (RGBB) of the Galactic bulge, the most metal-rich RGBB ever detected. The RGBB luminosity functions peaks at the expected brightness, but its number density is very low relative to Galactic globular…

We describe a new method for robustly testing theoretical predictions of red giant evolution near the tip of the giant branch. When theoretical cumulative luminosity functions are shifted to align the tip in I-band and normalized at a…

This paper discusses low mass, metal poor stars, presenting new evolutionary computations which take into account the inward diffusion of both He and heavy elements during the H burning phase. The investigation has been extended to He…

I discuss the age and helium abundance of the Galactic bulge stellar population. I present examples as to how age and helium abundance can be degenerate observationally, and thus, how unstated assumptions of the helium-metallicity relation…

Diffusion of atoms can be important during quiescent phases of stellar evolution. Particularly in the very thin inert envelopes of subdwarf B stars, diffusive movements will considerably change the envelope structure and the surface…

It has been known for a long time that some red giants in globular clusters exhibit large star-to-star variations in the abundances of light elements that are not exhibited by field giants. This fact can be taken as evidence that the extra…

We compare model predictions to observations of star counts in the red giant branch bump (RGBB) relative to the number density of first-ascent red giant branch at the magnitude of the RGBB, $EW_{RGBB}$. The predictions are shown to exceed…