On the red-giant luminosity bump

@article{ChristensenDalsgaard2015OnTR,
  title={On the red-giant luminosity bump},
  author={J. Christensen-Dalsgaard},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2015},
  volume={453},
  pages={666-670}
}
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 non-monotonic variation of luminosity causes an accumulation of stars, known as the `bump', in the distribution of stars in the colour-magnitude diagrams of stellar clusters, which has substantial diagnostic potential. Here I present numerical results on this… 

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References

SHOWING 1-10 OF 15 REFERENCES

Star Counts across the Red Giant Branch Bump and Below

We present a new observable—Rbump—which is the ratio between the star counts across the red giant branch (RGB) bump and fainter RGB stars to investigate the occurrence of a deep-mixing phenomenon

ASTEROSEISMIC ANALYSIS OF THE INTERNAL STRUCTURE AND EVOLUTION OF RED GIANT BRANCH BUMP STARS

The “bump” is a prominent feature of the red giant branch (RGB) luminosity function of stellar clusters. Through constructing a grid of models with different masses and metallicities to study the

The luminosity function on the subgiant branch of 47 Tucanae A comparison of observation and theory

Photographic photometry has been obtained for 1200 stars in the magnitude range of V = 13.5 to 17.5 in the field of the Galactic globular cluster 47 Tucanae and used to form both a color-magnitude

Red Giant Branch Stars: The Theoretical Framework

Theoretical predictions of red giant branch stars’ effective temperatures, colors, luminosities, and surface chemical abundances are a necessary tool for the astrophysical interpretation of the

The Red Giant Branch luminosity function bump

We present observational estimates of the magnitude difference between the luminosity function red giant branch bump and the horizontal branch (∆F555W bump ), and of star counts in the bump region

A critical investigation on the discrepancy between the observational and the theoretical red giant luminosity function ‘bump’

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

The development of the red giant branch. II - Astrophysical properties

Evolutionary sequences developed in another paper are used here to investigate the properties of the red giant branch (RGB) phase transition. Results are found for compositions in the range Y(MS)

STRUCTURAL GLITCHES NEAR THE CORES OF RED GIANTS REVEALED BY OSCILLATIONS IN G-MODE PERIOD SPACINGS FROM STELLAR MODELS

With recent advances in asteroseismology it is now possible to peer into the cores of red giants, potentially providing a way to study processes such as nuclear burning and mixing through their

Diagnostics of stellar modelling from spectroscopy and photometry of globular clusters

We conduct a series of comparisons between spectroscopic and photometric observations of globular clusters and stellar models to examine their predictive power. Data from medium-to-high resolution

Red giant branch bump star counts in data and stellar models

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,