Related papers: Photometric Oscillations of Low Luminosity Red Gia…
The influence of rotation on the properties of red giants is studied in the context of the asteroseismic modelling of these stars. While red giants exhibit low surface rotational velocities, we find that the rotational history of the star…
A growing number of solar-like oscillations has been detected in red giant stars thanks to CoRoT and Kepler space-crafts. The seismic data gathered by CoRoT on red giant stars allow us to test mode driving theory in physical conditions…
The success of asteroseismology relies heavily on our ability to identify the frequency patterns of stellar oscillation modes. For stars like the Sun this is relatively easy because the mode frequencies follow a regular pattern described by…
Context: The study of stellar structure and evolution depends crucially on accurate stellar parameters. The photometry from space telescopes has provided superb data that allowed asteroseismic characterisation of thousands of stars.…
We have used AAVSO visual and photoelectric V data, and the AAVSO time-series package VSTAR and the Lomb-Scargle time-series algorithm to determine improved pulsation periods, "long secondary periods" (LSPs). and their amplitudes in 51…
The Kepler space telescope has provided time series of red giants of such unprecedented quality that a detailed asteroseismic analysis becomes possible. For a limited set of about a dozen red giants, the observed oscillation frequencies…
For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and directly opposite from the inner and outer regions of the Galaxy.…
The space missions CoRoT and Kepler have provided photometric data of unprecedented quality for asteroseismology. A very rich oscillation pattern has been discovered for red giants, including mixed modes that are used to decipher the red…
The currently available Kepler light curves contain an outstanding amount of information but a detailed analysis of the individual oscillation modes in the observed power spectra, also known as peak bagging, is computationally demanding and…
The Kepler space mission provided high-quality light curves for more than 16 000 red giants. The global stellar oscillations extracted from these light curves carry information about the interior of the stars. Several hundred red giants…
We studied solar-like oscillations in 115 red giants in the three open clusters NGC 6791, NGC 6811, and NGC 6819, based on photometric data covering more than 19 months with NASA's Kepler space telescope. We present the asteroseismic…
In the fourth paper of this series, we present the metallicity-dependent Sloan Digital Sky Survey (SDSS) stellar color loci of red giant stars, using a spectroscopic sample of red giants in the SDSS Stripe 82 region. The stars span a range…
Thanks to the high quality data of space missions, the detection of mixed modes has become possible in numerous stars. In this work, we investigate how the mixing character of dipolar mixed modes changes with stellar evolution, as well as…
Variations of ~0.4 mag are expected in the I-band absolute magnitude of red clump giants, M_I^RC, as a function of both stellar age and metallicity. This regardless of some potential theoretical uncertainties. Due to the quite large…
We analysed solar-like oscillations in 1523 $\textit{Kepler}$ red giants which have previously been misclassified as subgiants, with predicted $\nu_{\rm max}$ values (based on the Kepler Input Catalogue) between 280$\mu$Hz to 700$\mu$Hz. We…
High resolution spectra of 110 selected red giant stars in the globular cluster M15 (NGC 7078) were obtained with Hectochelle at the MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders containing Halpha and Ca H & K are…
We present the results from the discovery and study of ~3000 chromospherically active giant and subgiant stars toward the Galactic bulge. We find that these stars are predominantly RS CVn binaries with rotation periods between 10 and 100…
The first catalog of chromospherically active and ellipsoidal variable stars in the OGLE database is presented. The periods, the observed magnitudes and colors, their values free of interstellar extinction, and Fourier coefficients of light…
The fraction of low-mass (LM) stars (M <= 1.5 Msun) showing photospheric activity in their light curve is larger on the horizontal branch (HB) than during the previous red giant branch (RGB) phase, while the opposite trend has been observed…
The orbital angular momentum of a close-orbiting giant planet can be sufficiently large that, if transferred to the envelope of the host star during the red giant branch (RGB) evolution, it can spin-up the star's rotation to unusually large…