Skip to Main content Skip to Navigation
Journal articles

Helium signature in red giant oscillation patterns observed by Kepler

Abstract : Context. The space-borne missions CoRoT and Kepler have provided a large amount of precise photometric data. Among the stars observed, red giants show a rich oscillation pattern that allows their precise characterization. Long-duration observations allow for investigating the fine structure of this oscillation patternAims. A common pattern of oscillation frequency was observed in red giant stars, which corresponds to the second-order development of the asymptotic theory. This pattern, called the universal red giant oscillation pattern, describes the frequencies of stellar acoustic modes. We aim to investigate the deviations observed from this universal pattern, thereby characterizing them in terms of the location of the second ionization zone of helium. We also show how this seismic signature depends on stellar evolution.Methods. We measured the frequencies of radial modes with a maximum likelihood estimator method, then we identified a modulation corresponding to the departure from the universal oscillation pattern.Results. We identify the modulation component of the radial mode frequency spacings in more than five hundred red giants. The variation in the modulation that we observe at different evolutionary states brings new constraints on the interior models for these stars. We also derive an updated form of the universal pattern that accounts for the modulation and provides highly precise radial frequencies.
Document type :
Journal articles
Complete list of metadatas

Cited literature [13 references]  Display  Hide  Download

https://hal-cea.archives-ouvertes.fr/cea-01300602
Contributor : Edp Sciences <>
Submitted on : Monday, April 11, 2016 - 11:46:27 AM
Last modification on : Wednesday, September 23, 2020 - 4:37:04 AM
Long-term archiving on: : Monday, November 14, 2016 - 11:53:23 PM

File

aa25064-14.pdf
Publication funded by an institution

Identifiers

Citation

M. Vrard, B. Mosser, C. Barban, K. Belkacem, Y. Elsworth, et al.. Helium signature in red giant oscillation patterns observed by Kepler. Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 579, pp.A84. ⟨10.1051/0004-6361/201425064⟩. ⟨cea-01300602⟩

Share

Metrics

Record views

509

Files downloads

674