Speaker
Mr
Jie Yu
(University of Sydney)
Description
The Kepler mission has provided exquisite data to perform ensemble asteroseismic analysis on evolved stars. In this work we systematically characterize the oscillation power excess for 16,136 oscillating red giants, using full-length long-cadence data. We produced a homogeneous catalog of seismic masses, radii, and surface gravities and investigated the properties of the oscillation power excess as a function of seismic mass and metallicity provided by LAMOST. We find that low mass helium-core burning (HeB) stars show the same oscillation amplitude while higher mass HeB stars show lower amplitude compared to RGB stars. We also discovered that the power excess width is an increasing function of stellar mass. We furthermore provide the first evidence for a dependence of the oscillation amplitude and power excess width on metallicity, with metal-rich red giants having higher oscillation and background-granulation amplitudes and narrower excess width. Our asteroseismic stellar properties can be used as reliable distance indicators and age proxies for dating and mapping stellar populations observed by Kepler. It will also provide an excellent opportunity to test asteroseismology using Gaia parallaxes, and lift degeneracies in deriving atmospheric parameters in large spectroscopic surveys such as APOGEE and LAMOST.
Primary author
Mr
Jie Yu
(University of Sydney)
Co-authors
Dr
Daniel Huber
(University of Hawii)
Dr
Dennis Stello
(University of New South Wales)
Mr
Marc Hon
(University of new south wales)
Prof.
Timothy Bedding
(University of Sydney)