%0 Journal Article %T Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars %+ Sydney Institute for Astronomy (SIfA) %+ Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA) %+ Institut d'Astrophysique et de Géophysique [Liège] %+ Instituut voor Sterrenkunde [Leuven] %+ Danish AsteroSeismology Centre (DASC) %+ School of Physics and Astronomy %+ Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)) %+ Institut d'astrophysique spatiale (IAS) %+ Global Telescope %+ Eureka Scientific %+ Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma) %+ Space Telescope Science Institute (STSci) %+ NASA Ames Research Center (ARC) %+ Department of Physics and Astronomy [Iowa City] %+ Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA) %+ Indian Institute of Astrophysics (IIA) %+ Département des Sciences et Gestion de l'Environnement/Océanologie [Liège] %+ Max-Planck-Institut für Astrophysik (MPA) %+ Istituto Nazionale di Astrofisica (INAF) %A R. Bedding, Timothy %A Mosser, Benoit %A Huber, Daniel %A Montalbán, Josefina %A Beck, Paul %A Christensen-Dalsgaard, Jørgen %A P. Elsworth, Yvonne %A A. García, Rafael %A Miglio, Andrea %A Stello, Dennis %A R. White, Timothy %A de Ridder, Joris %A Hekker, Saskia %A Aerts, Conny %A Barban, Caroline %A Belkacem, Kevin %A Broomhall, Anne-Marie %A M. Brown, Timothy %A L. Buzasi, Derek %A Carrier, Fabien %A J. Chaplin, William %A Di Mauro, Maria Pia %A Dupret, Marc-Antoine %A Frandsen, Søren %A L. Gilliland, Ronald %A Goupil, Marie-Jo %A M. Jenkins, Jon %A Kallinger, Thomas %A Kawaler, Steven %A Kjeldsen, Hans %A Mathur, Savita %A Noels, Arlette %A Silva Aguirre, Victor %A Ventura, Paolo %< avec comité de lecture %@ 0028-0836 %J Nature %I Nature Publishing Group %V 471 %N 7340 %P 608-611 %8 2011 %D 2011 %R 10.1038/nature09935 %Z Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]Journal articles %X 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 issues in our understanding of red giants include uncertainties in the amount of mass lost at the surface before helium ignition and the amount of internal mixing from rotation and other processes. Progress is hampered by our inability to distinguish between red giants burning helium in the core and those still only burning hydrogen in a shell. Asteroseismology offers a way forward, being a powerful tool for probing the internal structures of stars using their natural oscillation frequencies. Here we report observations of gravity-mode period spacings in red giants that permit a distinction between evolutionary stages to be made. We use high-precision photometry obtained by the Kepler spacecraft over more than a year to measure oscillations in several hundred red giants. We find many stars whose dipole modes show sequences with approximately regular period spacings. These stars fall into two clear groups, allowing us to distinguish unambiguously between hydrogen-shell-burning stars (period spacing mostly ~50 seconds) and those that are also burning helium (period spacing ~100 to 300 seconds) %G English %2 https://cea.hal.science/cea-00904006/document %2 https://cea.hal.science/cea-00904006/file/Bemo.pdf %L cea-00904006 %U https://cea.hal.science/cea-00904006 %~ OBSPM %~ CEA %~ INSU %~ CNRS %~ UNIV-PSUD %~ CNES %~ LESIA %~ OPENAIRE %~ DSM-IRFU %~ IRFU-AIM %~ PSL %~ UNIV-PARIS-SACLAY %~ UNIV-PSUD-SACLAY %~ CEA-DRF %~ SORBONNE-UNIVERSITE %~ SU-INF-2018 %~ SU-SCIENCES %~ UNIV-PARIS %~ UP-SCIENCES %~ OBSPM-PSL %~ SU-TI %~ GS-PHYSIQUE %~ ALLIANCE-SU %~ IAS