Related papers: [C/N] Ages for Red Giants and their Implications f…
The detection of mixed modes in red giants with space missions CoRoT and Kepler has revealed their deep internal structure. These modes allow us to characterize the pattern of pressure modes (through the measurement of their asymptotic…
Stellar age estimates are often calculated by interpolating a star's properties in a grid of models. However, different model grids will give different ages for the same star. We used the open cluster M67 to compare four different model…
We have discovered a population of extremely red galaxies at $z\simeq 1.5$ which have apparent stellar ages of $\gs 3$ Gyr, based on detailed spectroscopy in the rest-frame ultraviolet. In order for galaxies to have existed at the high…
We provide a status report on the determination of stellar ages from asteroseismology for stars of various masses and evolutionary stages. The ability to deduce the ages of stars with a relative precision of typically 10 to 20% is a unique…
Determining stellar ages is challenging, as it depends on other stellar parameters in a non-linear way and often relies on stellar evolution models to infer the underlying relation between these parameters and age. This complexity increases…
(ABRIDGED) We use the 17th data release of the second phase of the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) to provide a homogenous census of N-rich red giant stars across the Milky Way (MW). We report a total of…
We present the third and final data release of the K2 Galactic Archaeology Program (K2 GAP) for Campaigns C1-C8 and C10-C18. We provide asteroseismic radius and mass coefficients, $\kappa_R$ and $\kappa_M$, for $\sim 19,000$ red giant…
Owing to their simplicity and ease of application, seismic scaling relations are widely used to determine the properties of stars exhibiting solar-like oscillations, such as solar twins and red giants. So far, no seismic scaling relations…
The CoRoT 5-month long observation runs give us the opportunity to analyze a large variety of red-giant stars and to derive fundamental stellar parameters from their asteroseismic properties. We perform an analysis of more than 4\,600 CoRoT…
Red giants are evolved stars that have exhausted the supply of hydrogen in their cores and instead burn hydrogen in a surrounding shell. Once a red giant is sufficiently evolved, the helium in the core also undergoes fusion. Outstanding…
We show that collisions with stellar--mass black holes can partially explain the absence of bright giant stars in the Galactic Centre, first noted by Genzel et al, 1996. We show that the missing objects are low--mass giants and AGB stars in…
Red Giant stars host solar-like oscillations which have mixed character, being sensitive to conditions both in the outer convection zone and deep within the interior. The properties of these modes are sensitive to both core rotation and…
The surface rotations of some red giants are so fast that they must have been spun up by tidal interaction with a close companion, either another star, a brown dwarf, or a planet. We focus here on the case of red giants that are spun up by…
Using new narrowband color observations of early-type galaxies in clusters, we reconstruct the color-magnitude relation (CMR) with a higher degree of accuracy than previous work. We then use the spectroscopically determined ages and…
We investigate the origin of the evolution of the population-averaged size of quenched galaxies (QGs) through a spectroscopic analysis of their stellar ages. The two most favoured scenarios for this evolution are either the size growth of…
The combination of asteroseismologically-measured masses with abundances from detailed analyses of stellar atmospheres challenges our fundamental knowledge of stars and our ability to model them. Ancient red-giant stars in the Galactic…
State-of-the-art stellar structure and evolution codes fail to adequately describe turbulent convection. For stars with convective envelopes, such as red giants, this leads to an incomplete depiction of the surface layers. As a result, the…
We use a sample of ~16,000 non-emission line galaxies from the SDSS to investigate the physical parameters underlying the well-known color-magnitude and color-sigma relations. Galaxies are sorted in terms of velocity dispersions (sigma),…
Aims: We investigate the change in the surface abundance of $^{12}$C during the evolution along the AGB, aiming to constrain third dredge-up models. Methods: High-resolution, near-infrared spectra of a sample of AGB stars in the LMC cluster…
Red supergiants (RSGs) are an evolved He-burning phase in the lifetimes of moderately high mass (10 - 25 solar mass) stars. The physical properties of these stars mark them as an important and extreme stage of massive stellar evolution, but…