Related papers: On the red-giant luminosity bump
The evolution of low-mass stars into red giants is still poorly understood. During this evolution the core of the star contracts and, simultaneously, the envelope expands -- a process known as the `mirror'. Additionally, there is a short…
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 a scenario to explain the lithium-rich phase which occurs on the red giant branch at the so-called bump in the luminosity function. The high transport coefficients required to enhance the surface lithium abundance are obtained in…
The red-giant branch bump provides valuable information for the investigation of the internal structure of low-mass stars. Because current models are unable to accurately predict the occurrence and efficiency of mixing processes beyond…
Low mass stars (< 2-2.5 M_sun) exhibit, at all the stages of their evolution, signatures of processes that require challenging modeling beyond the standard stellar theory. In this paper we focus on their peculiarities while they climb the…
We suggest that the gap observed at 20,000 K in the horizontal branches of several Galactic globular clusters is caused by a small amount of extra mass loss which occurs when stars start to "peel off" the red giant branch (RGB), i.e., when…
Red giants are stars in the late stages of stellar evolution. Because they have exhausted the supply of hydrogen in their core, they burn the hydrogen in the surrounding shell. Once the helium in the core starts fusing, the star enters the…
We performed a detailed study of the evolution of the luminosity of He-ignition stage and of the red giant branch bump luminosity during the red giant branch phase transition for various metallicities. To this purpose we calculated a grid…
The advent of ultra-precise photometry space missions enable the possibility of investigating stellar interior with mixed modes. The structural variations induced by the discontinuity of the chemical composition left behind during the first…
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…
The partial mixing of matter between the radiative envelope and the convective core in the early type B--star produces an additional increase of star luminosity during the main sequence evolution. The high quality data on stellar mass and…
The efficiency of convection in stars affects many aspects of their evolution and remains one of the key-open questions in stellar modelling. In particular, the size of the mixed core in core-He-burning low-mass stars is still uncertain and…
We compute full evolutionary sequences of red giant branch stars close to the luminosity bump by including state of the art composition transport prescriptions for the thermohaline mixing regimes. In particular we adopt a self-consistent…
The existence of star-to-star light-element abundance variations (multiple populations, MPs) in massive Galactic and extragalactic star clusters older than about 2 Gyr is by now well established. Photometry of red giant branch (RGB) stars…
During the red giant phase, stars loose mass at the highest rate since birth. The mass-loss rate is not fixed, but varies from star-to-star by up to 5\%, resulting in variations of the star's luminosity at the tip of the red giant branch…
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…
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…
In this research we use a large sample of field metal-poor stars ([Fe/H]<-1) in different evolutionary phases to prove observationally that (small mass) subgiants (stars brighter than the first dredge-up and fainter than the RGB bump) have…
Most current models of low mass red giant stars do not reproduce the observed position of the red giant branch luminosity bump, a diagnostic of the maximum extent of the convective envelope during the first dredge up. Global asteroseismic…
Red Clump stars have been found to be enhanced in lithium relative to stars at the tip of the Red Giant Branch (TRGB), which is unexpected in current stellar models. At the TRGB, stars undergo the helium flash, during which helium burning…