Non-radial oscillation modes with long lifetimes in giant stars

  title={Non-radial oscillation modes with long lifetimes in giant stars},
  author={Joris De Ridder and Caroline Barban and Frédéric Baudin and Fabien Carrier and A. P. Hatzes and Saskia Hekker and Thomas Kallinger and Werner W. Weiss and Annie Baglin and Michel Auvergne and R'eza Samadi and Pierre Barge and Magali Deleuil},
Towards the end of their lives, stars like the Sun greatly expand to become red giant stars. Such evolved stars could provide stringent tests of stellar theory, as many uncertainties of the internal stellar structure accumulate with age. Important examples are convective overshooting and rotational mixing during the central hydrogen-burning phase, which determine the mass of the helium core, but which are not well understood. In principle, analysis of radial and non-radial stellar oscillations… 
Theoretical amplitudes and lifetimes of non-radial solar-like oscillations in red giants
Context. Solar-like oscillations have been observed in numerous red giants from ground and from space. An important question arises: could we expect to detect non-radial modes probing the internal
Theoretical power spectra of mixed modes in low-mass red giant stars
Context. CoRoT and Kepler observations of red giant stars revealed very rich spectra of non-radial solar-like oscillations. Of particular interest was the detection of mixed modes that exhibit
Solar-like and Mira-like oscillations of stars — A uniform excitation mechanism
Using a non-local and time-dependent theory of convection, we have calculated the linear non-adiabatic oscillations of the radial and low-degree F-p39 modes for evolutionary models from the main
Asteroseismology of red giant stars
If appropriately excited, a star will oscillate like a giant spherical instrument. In most stars, including the Sun, surface convection provides the excitation mechanism (Goldreich and Keeley, 1977).
Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes
An increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants is reported using the rotational frequency splitting of recently detected ‘mixed modes’, which confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior.
Solar-Like Oscillators in the Kepler Era: A Review
  • J. Jackiewicz
  • Physics
    Frontiers in Astronomy and Space Sciences
  • 2020
Many late-type stars across the Milky Way exhibit observable pulsations similar to our Sun that open up a window into stellar interiors. The NASA Kepler mission, a space-based photometric telescope,
We have measured solar-like oscillations in red giants using time-series photometry from the first 34 days of science operations of the Kepler Mission. The light curves, obtained with 30 minute
Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars
Observations of gravity-mode period spacings in red giants that permit a distinction between evolutionary stages to be made, using high-precision photometry obtained by the Kepler spacecraft to measure oscillations in several hundred red giants.
On the asymptotic acoustic-mode phase in red giant stars and its dependence on evolutionary state
Asteroseismic investigations based on the wealth of data now available,in particular from the CoRoT and Kepler missions, require a good understanding of the relation between the observed quantities
Radial mode widths in red giant stars spectra observed by Kepler
The Kepler space mission has observed many solar-like pulsators, and helped to decipher their fundamental parameters (e.g: mass, radius, rotation). Most of the achievements recently obtained in that


The Discovery of Stellar Oscillations in the Planet-hosting Giant Star β Geminorum
We present the results of a long time series of precise stellar radial velocity measurements of the planet hosting K giant star β Geminorum. A total of 20 hr of observations spanning three nights
Oscillations of α UMa and other red giants
There is growing observational evidence that the variability of red giants could be caused by self-excitation of global modes of oscillation. The most recent evidence of such oscillations was
I present details of the variations of several hundred red giant stars on timescales of a few hours to a few days from Hubble Space Telescope (HST) observations of a low-extinction galactic bulge
Oscillation mode lifetimes in $\xi\,$Hydrae: will strong mode damping limit asteroseismology of red giant stars?
We introduce a new method to measure frequency separations and mode lifetimes of stochastically excited and damped oscillations, so-called solar-like oscillations. Our method shows that velocity data
Evolutionary Model and Oscillation Frequencies for α Ursae Majoris: A Comparison with Observations
It is found that, by adopting the correct metallicity and for a normal helium abundance, only models in the mass range of 4.0-4.5 M middle dot in circle fall within the observational error box for alpha UMa A.
Amplitudes of Stellar Oscillations: The Implications for Asteroseismology
There are no good predictions for the amplitudes expected from solar-like oscillations in other stars. In the absence of a definitive model for convection, which is thought to be the mechanism that
Multisite campaign on the open cluster M67 – II. Evidence for solar-like oscillations in red giant stars
Measuring solar-like oscillations in an ensemble of stars i n a cluster, holds promise for testing stellar structure and evolution more stringently than just fitting parameters to single field stars.
Oscillating K Giants with the WIRE Satellite: Determination of Their Asteroseismic Masses
Mass estimates of K giants are generally very uncertain. Traditionally, stellar masses of single field stars are determined by comparing their location in the Hertzsprung-Russell diagram with stellar
Detection of solar-like oscillations in the red giant star $\epsilon$ Ophiuchi by MOST spacebased photometry
Context. Solar-like oscillations have been discovered in a few red giants, including ϵ  Oph, through spectroscopy. Acoustic modes around 60  μ Hz were clearly seen in this star, but daily aliasing of
K Giants in 47 Tucanae: Detection of a New Class of Variable Stars
We report the discovery of variability among K giants in the globular cluster 47 Tucanae, using a time series of U exposures with the Hubble Space Telescope. The variables lie along a narrow band in