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The excitation of solar-like oscillations in a δ Sct star by efficient envelope convection


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Delta Scuti (δ Sct)1 stars are opacity-driven pulsators with masses of 1.5–2.5M, their pulsations resulting from the varying ionization of helium. In less massive stars2 such as the Sun, convection transports mass and energy through the outer 30 per cent of the star and excites a rich spectrum of resonant acoustic modes. Based on the solar example, with no firm theoretical basis, models predict that the convective envelope in δ Sct stars extends only about 1 per cent of the radius3, but with sufficient energy to excite solar-like oscillations4,5. This was not observed before the Kepler mission6, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the δ Sct star HD 187547, implying that surface convection operates efficiently in stars about twice as massive as the Sun, as the ad hoc models predicted.

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Figure 1: Fourier amplitude spectra of the Kepler light curve of HD 187547.
Figure 2: Time-Fourier spectrum.
Figure 3: Échelle diagram of HD 187547.

Change history

  • 29 September 2011

    The labelling of the Fig. 1c y-axis was corrected.


  1. Breger, M. in Delta Scuti and Related Stars (ASP Conf. Ser. Vol. 210) (eds Breger, M. & Montgomery, M.) 3–42 (Astronomical Society of the Pacific, 2000)

    Google Scholar 

  2. Chaplin, W. J. et al. Ensemble asteroseismology of solar-type stars with the NASA Kepler mission. Science 332, 213–216 (2011)

    Article  ADS  CAS  Google Scholar 

  3. Kallinger, T. & Matthews, J. M. Evidence for granulation in early A-type stars. Astrophys. J. 711, L35–L39 (2010)

    Article  ADS  Google Scholar 

  4. Houdek, G., Balmforth, N. J., Christensen-Dalsgaard, J. & Gough, D. O. Amplitudes of stochastically excited oscillations in main-sequence stars. Astron. Astrophys. 351, 582–596 (1999)

    ADS  Google Scholar 

  5. Samadi, R., Goupil, M.-J. & Houdek, G. Solar-like oscillations in delta Scuti stars. Astron. Astrophys. 395, 563–571 (2002)

    Article  ADS  Google Scholar 

  6. Koch, D. G. et al. Kepler mission design, realized photometric performance, and early science. Astrophys. J. 713, L79–L86 (2010)

    Article  ADS  CAS  Google Scholar 

  7. Preston, G. W. The chemically peculiar stars of the upper main sequence. Annu. Rev. Astron. Astrophys. 12, 257–277 (1974)

    Article  ADS  Google Scholar 

  8. Asplund, M., Grevesse, N., Sauval, A. J. & Scott, P. The chemical composition of the Sun. Annu. Rev. Astron. Astrophys. 47, 481–522 (2009)

    Article  ADS  CAS  Google Scholar 

  9. Carquillat, J.-M. & Prieur, J.-L. Contribution to the search for binaries among Am stars. VIII. New spectroscopic orbits of eight systems and statistical study of a sample of 91 Am stars. Mon. Not. R. Astron. Soc. 380, 1064–1078 (2007)

    Article  ADS  CAS  Google Scholar 

  10. Turcotte, S., Richer, J., Michaud, G. & Christensen-Dalsgaard, J. The effect of diffusion on pulsations of stars on the upper main sequence—δ Scuti and metallic A stars. Astron. Astrophys. 360, 603–616 (2000)

    ADS  CAS  Google Scholar 

  11. Balona, L. et al. Kepler observations of Am stars. Mon. Not. R. Astron. Soc. 414, 792–800 (2011)

    Article  ADS  CAS  Google Scholar 

  12. Handler, G. Confirmation of simultaneous p and g mode excitation in HD 8801 and γ Peg from time-resolved multicolour photometry of six candidate ‘hybrid’ pulsators. Mon. Not. R. Astron. Soc. 398, 1339–1351 (2009)

    Article  ADS  CAS  Google Scholar 

  13. Kurtz, D. W. Rapidly oscillating AP stars. Mon. Not. R. Astron. Soc. 200, 807–859 (1982)

    Article  ADS  Google Scholar 

  14. Aurière, M. et al. No detection of large-scale magnetic fields at the surfaces of Am and HgMn stars. Astron. Astrophys. 523 A40 10.1051/0004-6361/201014848 (2010)

    Article  Google Scholar 

  15. Stello, D., Chaplin, W. J., Basu, S., Elsworth, Y. & Bedding, T. R. The relation between Δν and ν max for solar-like oscillations. Mon. Not. R. Astron. Soc. 400L, L80–L84 (2009)

    Article  ADS  Google Scholar 

  16. Houdek, G. Solar-type variables. AIP Conf. Proc. 1170, 519–530 (2009)

    Article  ADS  Google Scholar 

  17. Samadi, R., Belkacem, K., Goupil, M.-J., Kupka, F. & Dupret, M.-A. Solarlike oscillation amplitudes and line-widths as a probe for turbulent convection in stars. Proc. Int. Astron. Un. 239, 349–357 (2007)

    Google Scholar 

  18. Kjeldsen, H. et al. The amplitude of solar oscillations using stellar techniques. Astrophys. J. 682, 1370–1375 (2008)

    Article  ADS  CAS  Google Scholar 

  19. Ballot, J., Barban, C. & van’t Veer-Menneret, C. Visibilities and bolometric corrections for stellar oscillation modes observed by Kepler. Astron. Astrophys. 531 A124 10.1051/0004-6361/201016230 (2011)

    Article  ADS  Google Scholar 

  20. Kjeldsen, H. & Bedding, T. R. Amplitudes of solar-like oscillations: a new scaling relation. Astron. Astrophys. 529 L8 10.1051/0004-6361/201116789 (2011)

    Article  ADS  MATH  Google Scholar 

  21. Michel, E. et al. Intrinsic photometric characterisation of stellar oscillations and granulation. Astron. Astrophys. 495, 979–987 (2009)

    Article  ADS  Google Scholar 

  22. Gruberbauer, M., Kallinger, T., Weiss, W. W. & Guenther, D. B. On the detection of Lorentzian profiles in a power spectrum: a Bayesian approach using ignorance priors. Astron. Astrophys. 506, 1043–1053 (2009)

    Article  ADS  Google Scholar 

  23. Chaplin, W. J., Houdek, G., Karoff, C., Elsworth, Y. & New, R. Mode lifetimes of stellar oscillations. Implications for asteroseismology. Astron. Astrophys. 500, L21–L24 (2009)

    Article  ADS  Google Scholar 

  24. Baudin, F. et al. Amplitudes and lifetimes of solar-like oscillations observed by CoRoT. Red-giant versus main-sequence stars. Astron. Astrophys. 529 A84 10.1051/0004-6361/201014037 (2011)

    Article  Google Scholar 

  25. Samadi, R., Ludwig, H.-G., Belkacem, K., Goupil, M. J. & Dupret, M.-A. The CoRoT target HD 49933. I. Effect of the metal abundance on the mode excitation rates. Astron. Astrophys. 509 A15 10.1051/0004-6361/200911867 (2010)

    Article  CAS  Google Scholar 

  26. Chaplin, W. J. et al. On model predictions of the power spectral density of radial solar p modes. Mon. Not. R. Astron. Soc. 360, 859–868 (2005)

    Article  ADS  CAS  Google Scholar 

  27. Chang, H.-Y. & Gough, D. O. On the power distribution of solar p modes. Solar Phys. 181, 251–263 (1998)

    Article  ADS  Google Scholar 

  28. Pamyatnykh, A. A. in Delta Scuti and Related Stars (ASP Conf. Ser. Vol. 210) (eds Breger, M. & Montgomery, M. ) 215–246 (Astronomical Society of the Pacific, 2000)

    Google Scholar 

  29. Landstreet, J. D. et al. Atmospheric velocity fields in tepid main sequence stars. Astron. Astrophys. 503, 973–984 (2009)

    Article  ADS  CAS  Google Scholar 

  30. Belkacem, K. et al. Solar-like oscillations in a massive star. Science 324, 1540–1542 (2009)

    Article  ADS  CAS  Google Scholar 

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We thank the entire Kepler team, without whom these results would not be possible. V.A., G.Ha. and G.Ho. were supported by the Austrian Fonds zur Förderung der wissenschaftlichen Forschung. V.A. also thanks L. Fossati for his help. A.M. acknowledges the funding of AstroMadrid, who was also supported by Spanish grants. T.R.B. and D.S. acknowledge support from the Australian Reseach Council. T.L was supported by the Austrian Agency for International Cooperation in Education and Research. K.U. acknowledges financial support from the Deutsche Forschungsgemeinschaft. Funding for this Discovery mission is provided by NASA’s Science Mission Directorate.

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Authors and Affiliations



V.A. discovered the star among the Kepler targets, analysed it and found the solar-like oscillations (as a part of her PhD thesis), did spectroscopic analyses, frequency analyses, the test on the stochastic nature of the signal, and interpretations, and wrote the paper. G.Ha. had the idea for this project and supervised V.A., helped with analyses, interpretations and writing the paper. T.L.C. contributed to the analyses of the stochastic modes and also to the test on the stochastic nature of the signal. A.O.T. observed the target spectroscopically at Nordic Optical Telescope, identified the star as an Am star and did spectroscopic analyses. A.M. contributed to the statistical test on the nature of the stochastic signal. T.K. helped interpretations, data analyses and writing the paper, and delivered the mode lifetimes. D.S. helped with data analyses, writing the paper and made Fig. 2. A.G. helped with theoretical interpretations and the time-Fourier analyses. T.R.B. helped with interpretations and writing the paper. H.K. contributed to the analyses, also by supervising V.A., and is a member of the Kepler Asteroseismic Investigation Steering Committee. J.C-D. helped with the theoretical support, writing the paper and is a member of the Kepler Asteroseismic Investigation Steering Committee. T.L. confirmed the Am identification, excluding the Ap character of the star. G.C., A.F. and A.K. did spectroscopic analyses. P.D.C. was Principal Investigator and observer for the spectroscopic data from McDonald observatory. K.U. was Co-Investigator of the McDonald data and coordinated the ground-based observations. H.B. was Principal Investigator for the observations with the NARVAL spectrograph and did spectroscopic analyses. G.Ho. and P.L. helped with theoretical interpretations and writing the paper. D.W.K. helped with the Am classification and writing the paper and is leader of the delta Scuti working group of the Kepler Asteroseismic Science Consortium. J.V.C., C.A. and B.D.C. are part of the Kepler team and were involved in designing and operating the satellite. All co-authors contributed to discussions and commented on the manuscript.

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Correspondence to V. Antoci.

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Antoci, V., Handler, G., Campante, T. et al. The excitation of solar-like oscillations in a δ Sct star by efficient envelope convection. Nature 477, 570–573 (2011).

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