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1. Successful Asteroseismology for a Better Characterization of the Exoplanet HAT-P-7b

Author

Oshagh, M., Grigahcène, A., Benomar, O., Dupret, M. -A., Monteiro, M. J. P. F. G., Scuflaire, R., Santos, N. C., Oshagh, M., Grigahcène, A., Benomar, O., Dupret, M. -A., Monteiro, M. J. P. F. G., Scuflaire, R., and Santos, N. C.

Abstract

It is well known that asteroseismology is the unique technique permitting the study of the internal structure of pulsating stars using their pulsational frequencies, which is per se very important. It acquires an additional value when the star turns out to be a planet host. In this case, the asteroseismic study output may be a very important input for the study of the planetary system. With this in mind, we use the large time-span of the Kepler public data obtained for the star system HAT-P-7, first to perform an asteroseismic study of the pulsating star using Time-Dependent-Convection (TDC) models. Secondly, we make a revision of the planet properties in the light of the asteroseismic study., Comment: 4 pages, 2 figures, Published in the Stellar Pulsations, Astrophysics and Space Science Proceedings, Volume 31., p. 227, 2013

Published
2013
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2. Successful Asteroseismology for a Better Characterization of the Exoplanet HAT-P-7b

Author

Oshagh, M., Grigahcène, A., Benomar, O., Dupret, M. -A., Monteiro, M. J. P. F. G., Scuflaire, R., Santos, N. C., Oshagh, M., Grigahcène, A., Benomar, O., Dupret, M. -A., Monteiro, M. J. P. F. G., Scuflaire, R., and Santos, N. C.

Abstract

It is well known that asteroseismology is the unique technique permitting the study of the internal structure of pulsating stars using their pulsational frequencies, which is per se very important. It acquires an additional value when the star turns out to be a planet host. In this case, the asteroseismic study output may be a very important input for the study of the planetary system. With this in mind, we use the large time-span of the Kepler public data obtained for the star system HAT-P-7, first to perform an asteroseismic study of the pulsating star using Time-Dependent-Convection (TDC) models. Secondly, we make a revision of the planet properties in the light of the asteroseismic study., Comment: 4 pages, 2 figures, Published in the Stellar Pulsations, Astrophysics and Space Science Proceedings, Volume 31., p. 227, 2013

Published
2013
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3. Kepler observations of the high-amplitude δ Scuti star V2367 Cyg

Author

Balona, L. A., Lenz, P., Antoci, V., Bernabei, S., Catanzaro, G., Daszyńska-Daszkiewicz, J., Di Criscienzo, M., Grigahcène, A., Handler, G., Kurtz, D. W., Marconi, M., Molenda-Żakowicz, J., Moya, A., Nemec, J. M., Pigulski, A., Pricopi, D., Ripepi, V., Smalley, B., Suárez, J. C., Suran, M., Hall, J. R., Kinemuchi, K., Klaus, T. C., Balona, L. A., Lenz, P., Antoci, V., Bernabei, S., Catanzaro, G., Daszyńska-Daszkiewicz, J., Di Criscienzo, M., Grigahcène, A., Handler, G., Kurtz, D. W., Marconi, M., Molenda-Żakowicz, J., Moya, A., Nemec, J. M., Pigulski, A., Pricopi, D., Ripepi, V., Smalley, B., Suárez, J. C., Suran, M., Hall, J. R., Kinemuchi, K., and Klaus, T. C.

Published
2011

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

Author

Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., Clarke, B. D., Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., and Clarke, B. D.

Published
2011

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

Author

Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., Clarke, B. D., Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., and Clarke, B. D.

Published
2011

6. Kepler observations of the high-amplitude δ Scuti star V2367 Cyg

Author

Balona, L. A., Lenz, P., Antoci, V., Bernabei, S., Catanzaro, G., Daszyńska-Daszkiewicz, J., Di Criscienzo, M., Grigahcène, A., Handler, G., Kurtz, D. W., Marconi, M., Molenda-Żakowicz, J., Moya, A., Nemec, J. M., Pigulski, A., Pricopi, D., Ripepi, V., Smalley, B., Suárez, J. C., Suran, M., Hall, J. R., Kinemuchi, K., Klaus, T. C., Balona, L. A., Lenz, P., Antoci, V., Bernabei, S., Catanzaro, G., Daszyńska-Daszkiewicz, J., Di Criscienzo, M., Grigahcène, A., Handler, G., Kurtz, D. W., Marconi, M., Molenda-Żakowicz, J., Moya, A., Nemec, J. M., Pigulski, A., Pricopi, D., Ripepi, V., Smalley, B., Suárez, J. C., Suran, M., Hall, J. R., Kinemuchi, K., and Klaus, T. C.

Published
2011

7. Towards precise asteroseismology of solar-like stars

Author

Grigahcène, A., Dupret, M. -A., Sousa, S. G., Monteiro, M. J. P. F. G., Garrido, R., Scuflaire, R., Gabriel, M., Grigahcène, A., Dupret, M. -A., Sousa, S. G., Monteiro, M. J. P. F. G., Garrido, R., Scuflaire, R., and Gabriel, M.

Abstract

Adiabatic modeling of solar-like oscillations cannot exceed a certain level of precision for fitting individual frequencies. This is known as the problem of near surface effects on the mode physics. We present a theoretical study which addresses the problem of frequency precision in non-adiabatic models using a time-dependent convection treatment. We find that the number of acceptable model solutions is significantly reduced and more precise constraints can be imposed on the models. Results obtained for a specific star (beta Hydri) lead to very good agreement with both global and local seismic observables. This indicates that the accuracy of model fitting to seismic data is greatly improved when a more complete description of the interaction between convection and pulsation is taken into account., Comment: 4 pages, 2 figures. To be published in Astrophysics and Space Science Proceedings series (ASSP). Proceedings of the "20th Stellar Pulsation Conference Series: Impact of new instrumentation and new insights in stellar pulsations", 5-9 September 2011, Granada, Spain

Published
2011
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8. The excitation of solar-like oscillations in a delta Scuti star by efficient envelope convection

Author

Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., Clarke, B. D., Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., and Clarke, B. D.

Abstract

Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses of 1.5-2.5M$_{\odot}$, their pulsations resulting from the varying ionization of helium. In less massive stars 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 delta Sct stars extends only about 1 per cent of the radius, but with sufficient energy to excite solar-like oscillations. This was not observed before the Kepler mission, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the delta 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., Comment: to appear as a Letter to Nature

Published
2011
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9. Kepler observations of Am stars★

Author

Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., Girouard, F. R., Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., and Girouard, F. R.

Published
2011

10. Kepler observations of Am stars★

Author

Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., Girouard, F. R., Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., and Girouard, F. R.

Published
2011

11. Kepler observations of Am stars★

Author

Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., Girouard, F. R., Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., and Girouard, F. R.

Published
2011

12. Towards precise asteroseismology of solar-like stars

Author

Grigahcène, A., Dupret, M. -A., Sousa, S. G., Monteiro, M. J. P. F. G., Garrido, R., Scuflaire, R., Gabriel, M., Grigahcène, A., Dupret, M. -A., Sousa, S. G., Monteiro, M. J. P. F. G., Garrido, R., Scuflaire, R., and Gabriel, M.

Abstract

Adiabatic modeling of solar-like oscillations cannot exceed a certain level of precision for fitting individual frequencies. This is known as the problem of near surface effects on the mode physics. We present a theoretical study which addresses the problem of frequency precision in non-adiabatic models using a time-dependent convection treatment. We find that the number of acceptable model solutions is significantly reduced and more precise constraints can be imposed on the models. Results obtained for a specific star (beta Hydri) lead to very good agreement with both global and local seismic observables. This indicates that the accuracy of model fitting to seismic data is greatly improved when a more complete description of the interaction between convection and pulsation is taken into account., Comment: 4 pages, 2 figures. To be published in Astrophysics and Space Science Proceedings series (ASSP). Proceedings of the "20th Stellar Pulsation Conference Series: Impact of new instrumentation and new insights in stellar pulsations", 5-9 September 2011, Granada, Spain

Published
2011
Full Text
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13. The excitation of solar-like oscillations in a delta Scuti star by efficient envelope convection

Author

Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., Clarke, B. D., Antoci, V., Handler, G., Campante, T. L., Thygesen, A. O., Moya, A., Kallinger, T., Stello, D., Grigahcène, A., Kjeldsen, H., Bedding, T. R., Lüftinger, T., Christensen-Dalsgaard, J., Catanzaro, G., Frasca, A., De Cat, P., Uytterhoeven, K., Bruntt, H., Houdek, G., Kurtz, D. W., Lenz, P., Kaiser, A., Van Cleve, J., Allen, C., and Clarke, B. D.

Abstract

Delta Scuti (delta Sct) stars are opacity-driven pulsators with masses of 1.5-2.5M$_{\odot}$, their pulsations resulting from the varying ionization of helium. In less massive stars 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 delta Sct stars extends only about 1 per cent of the radius, but with sufficient energy to excite solar-like oscillations. This was not observed before the Kepler mission, so the presence of a convective envelope in the models has been questioned. Here we report the detection of solar-like oscillations in the delta 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., Comment: to appear as a Letter to Nature

Published
2011
Full Text
View/download PDF

14. Kepler observations of Am stars★

Author

Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., Girouard, F. R., Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., and Girouard, F. R.

Published
2011

15. Kepler observations: Light shed on the hybrid γ Doradus - δ Scuti pulsation phenomenon

Author

Grigahcène, A., Uytterhoeven, K., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J.A., Handler, G., Houdek, G., Kurtz, D.W., Marconi, M., Monteiro, M.J.P.F.G., Moya, A., Ripepi, V., Suárez, J.-C., Borucki, W.J., Brown, T.M., Christensen-Dalsgaard, J., Gilliland, R.L., Jenkins, J.M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Di Criscienzo, M., Dupret, M.-A., García, R.A., García Hernández, A., Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J.M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M.D., Ventura, R., Grigahcène, A., Uytterhoeven, K., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J.A., Handler, G., Houdek, G., Kurtz, D.W., Marconi, M., Monteiro, M.J.P.F.G., Moya, A., Ripepi, V., Suárez, J.-C., Borucki, W.J., Brown, T.M., Christensen-Dalsgaard, J., Gilliland, R.L., Jenkins, J.M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Di Criscienzo, M., Dupret, M.-A., García, R.A., García Hernández, A., Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J.M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M.D., and Ventura, R.

Published
2010

16. Atmospheric parameters and pulsational properties for a sample of δ Sct, γ Dor and hybrid Kepler targets★

Author

Catanzaro, G., Ripepi, V., Bernabei, S., Marconi, M., Balona, L., Kurtz, D. W., Smalley, B., Borucki, W. J., Bruntt, H., Christensen-Dalsgaard, J., Grigahcène, A., Kjeldsen, H., Koch, D. G., Monteiro, M. J. P. F. G., Suárez, J. C., Szabó, R., Uytterhoeven, K., Catanzaro, G., Ripepi, V., Bernabei, S., Marconi, M., Balona, L., Kurtz, D. W., Smalley, B., Borucki, W. J., Bruntt, H., Christensen-Dalsgaard, J., Grigahcène, A., Kjeldsen, H., Koch, D. G., Monteiro, M. J. P. F. G., Suárez, J. C., Szabó, R., and Uytterhoeven, K.

Published
2010

17. HYBRID γ DORADUS-δ SCUTI PULSATORS: NEW INSIGHTS INTO THE PHYSICS OF THE OSCILLATIONS FROMKEPLEROBSERVATIONS

Author

Grigahcène, A., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J. A., Handler, G., Houdek, G., Kurtz, D. W., Marconi, M., Monteiro, M. J. P. F. G., Moya, A., Ripepi, V., Suárez, J.-C., Uytterhoeven, K., Borucki, W. J., Brown, T. M., Christensen-Dalsgaard, J., Gilliland, R. L., Jenkins, J. M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Criscienzo, M. Di, Dupret, M.-A., García, R. A., Hernández, A. García, Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J. M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M. D., Ventura, R., Grigahcène, A., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J. A., Handler, G., Houdek, G., Kurtz, D. W., Marconi, M., Monteiro, M. J. P. F. G., Moya, A., Ripepi, V., Suárez, J.-C., Uytterhoeven, K., Borucki, W. J., Brown, T. M., Christensen-Dalsgaard, J., Gilliland, R. L., Jenkins, J. M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Criscienzo, M. Di, Dupret, M.-A., García, R. A., Hernández, A. García, Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J. M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M. D., and Ventura, R.

Published
2010

18. Kepler observations: Light shed on the hybrid γ Doradus - δ Scuti pulsation phenomenon

Author

Grigahcène, A., Uytterhoeven, K., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J.A., Handler, G., Houdek, G., Kurtz, D.W., Marconi, M., Monteiro, M.J.P.F.G., Moya, A., Ripepi, V., Suárez, J.-C., Borucki, W.J., Brown, T.M., Christensen-Dalsgaard, J., Gilliland, R.L., Jenkins, J.M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Di Criscienzo, M., Dupret, M.-A., García, R.A., García Hernández, A., Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J.M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M.D., Ventura, R., Grigahcène, A., Uytterhoeven, K., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J.A., Handler, G., Houdek, G., Kurtz, D.W., Marconi, M., Monteiro, M.J.P.F.G., Moya, A., Ripepi, V., Suárez, J.-C., Borucki, W.J., Brown, T.M., Christensen-Dalsgaard, J., Gilliland, R.L., Jenkins, J.M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Di Criscienzo, M., Dupret, M.-A., García, R.A., García Hernández, A., Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J.M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M.D., and Ventura, R.

Published
2010

19. HYBRID γ DORADUS-δ SCUTI PULSATORS: NEW INSIGHTS INTO THE PHYSICS OF THE OSCILLATIONS FROMKEPLEROBSERVATIONS

Author

Grigahcène, A., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J. A., Handler, G., Houdek, G., Kurtz, D. W., Marconi, M., Monteiro, M. J. P. F. G., Moya, A., Ripepi, V., Suárez, J.-C., Uytterhoeven, K., Borucki, W. J., Brown, T. M., Christensen-Dalsgaard, J., Gilliland, R. L., Jenkins, J. M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Criscienzo, M. Di, Dupret, M.-A., García, R. A., Hernández, A. García, Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J. M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M. D., Ventura, R., Grigahcène, A., Antoci, V., Balona, L., Catanzaro, G., Daszyńska-Daszkiewicz, J., Guzik, J. A., Handler, G., Houdek, G., Kurtz, D. W., Marconi, M., Monteiro, M. J. P. F. G., Moya, A., Ripepi, V., Suárez, J.-C., Uytterhoeven, K., Borucki, W. J., Brown, T. M., Christensen-Dalsgaard, J., Gilliland, R. L., Jenkins, J. M., Kjeldsen, H., Koch, D., Bernabei, S., Bradley, P., Breger, M., Criscienzo, M. Di, Dupret, M.-A., García, R. A., Hernández, A. García, Jackiewicz, J., Kaiser, A., Lehmann, H., Martín-Ruiz, S., Mathias, P., Molenda-Żakowicz, J., Nemec, J. M., Nuspl, J., Paparó, M., Roth, M., Szabó, R., Suran, M. D., and Ventura, R.

Published
2010

20. Atmospheric parameters and pulsational properties for a sample of δ Sct, γ Dor and hybrid Kepler targets★

Author

Catanzaro, G., Ripepi, V., Bernabei, S., Marconi, M., Balona, L., Kurtz, D. W., Smalley, B., Borucki, W. J., Bruntt, H., Christensen-Dalsgaard, J., Grigahcène, A., Kjeldsen, H., Koch, D. G., Monteiro, M. J. P. F. G., Suárez, J. C., Szabó, R., Uytterhoeven, K., Catanzaro, G., Ripepi, V., Bernabei, S., Marconi, M., Balona, L., Kurtz, D. W., Smalley, B., Borucki, W. J., Bruntt, H., Christensen-Dalsgaard, J., Grigahcène, A., Kjeldsen, H., Koch, D. G., Monteiro, M. J. P. F. G., Suárez, J. C., Szabó, R., and Uytterhoeven, K.

Published
2010

21. Theoretical study of $\gamma$ Doradus pulsations in pre-main sequence stars

Author

Bouabid, M. -P., Montalbán, J., Miglio, A., Dupret, M. -A., Grigahcène, A., Noels, A., Bouabid, M. -P., Montalbán, J., Miglio, A., Dupret, M. -A., Grigahcène, A., and Noels, A.

Abstract

The question of the existence of pre-main sequence (PMS) $\gamma$~Doradus ($\gamma$~Dor) has been raised by the observations of young clusters such as NGC~884 hosting $\gamma$~Dor members. We have explored the properties of $\gamma$~Dor type pulsations in a grid of PMS models covering the mass range $1.2 M_\odot < M_* < 2.5 M_\odot$ and we derive the theoretical instability strip (IS) for the PMS $\gamma$~Dor pulsators. We explore the possibility of distinguishing between PMS and MS $\gamma$~Dor by the behaviour of the period spacing of their high order $gravity$-modes ($g$-modes)., Comment: 5 pages, 6 figures, Proc. HELAS IV Conference, Lanzarote, February 2010. Eds T. Roca Cort\'es, P. Pall\'e and S. Jim\'enez Reyes. Accepted in Astron. Nach

Published
2010
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22. Might intermediate-order g modes observed in the CoRoT hybrid gamma Doradus/delta Scuti star HD 49434 be stochastically excited?

Author

Campante, T. L., Grigahcène, A., Suárez, J. C., Monteiro, M. J. P. F. G., Campante, T. L., Grigahcène, A., Suárez, J. C., and Monteiro, M. J. P. F. G.

Abstract

The primary target in the seismo-field of CoRoT, HD 49434, known to be a bona fide hybrid gamma Doradus/delta Scuti, shows excited intermediate-order g modes. Time-Dependent Convection models, however, predict a range in frequency that is stable to pulsations, between the simultaneously excited high-order g modes (gamma Dor) and low-order p and g modes (delta Sct). Furthermore, theoretical studies based on model computations of delta Sct stars suggest that stochastically excited modes are likely to be observed. A pertinent question would then be to ask: Might those observed intermediate-order g modes be stochastically excited? By employing a statistical method which searches for the signature of stochastic excitation in stellar pulsations, we investigate the nature of those modes with possible implications on the identification of their excitation mechanism. Preliminary results are rather inconclusive about the presence of stochastic excitation. A new analysis that thoroughly takes into account sampling effects is necessary in order to get more reliable results., Comment: 4 pages, 3 figures, submitted to Astronomische Nachrichten, to appear in the proceedings of the IV HELAS International Conference

Published
2010

23. Theoretical study of $\gamma$ Doradus pulsations in pre-main sequence stars

Author

Bouabid, M. -P., Montalbán, J., Miglio, A., Dupret, M. -A., Grigahcène, A., Noels, A., Bouabid, M. -P., Montalbán, J., Miglio, A., Dupret, M. -A., Grigahcène, A., and Noels, A.

Abstract

The question of the existence of pre-main sequence (PMS) $\gamma$~Doradus ($\gamma$~Dor) has been raised by the observations of young clusters such as NGC~884 hosting $\gamma$~Dor members. We have explored the properties of $\gamma$~Dor type pulsations in a grid of PMS models covering the mass range $1.2 M_\odot < M_* < 2.5 M_\odot$ and we derive the theoretical instability strip (IS) for the PMS $\gamma$~Dor pulsators. We explore the possibility of distinguishing between PMS and MS $\gamma$~Dor by the behaviour of the period spacing of their high order $gravity$-modes ($g$-modes)., Comment: 5 pages, 6 figures, Proc. HELAS IV Conference, Lanzarote, February 2010. Eds T. Roca Cort\'es, P. Pall\'e and S. Jim\'enez Reyes. Accepted in Astron. Nach

Published
2010
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24. Might intermediate-order g modes observed in the CoRoT hybrid gamma Doradus/delta Scuti star HD 49434 be stochastically excited?

Author

Campante, T. L., Grigahcène, A., Suárez, J. C., Monteiro, M. J. P. F. G., Campante, T. L., Grigahcène, A., Suárez, J. C., and Monteiro, M. J. P. F. G.

Abstract

The primary target in the seismo-field of CoRoT, HD 49434, known to be a bona fide hybrid gamma Doradus/delta Scuti, shows excited intermediate-order g modes. Time-Dependent Convection models, however, predict a range in frequency that is stable to pulsations, between the simultaneously excited high-order g modes (gamma Dor) and low-order p and g modes (delta Sct). Furthermore, theoretical studies based on model computations of delta Sct stars suggest that stochastically excited modes are likely to be observed. A pertinent question would then be to ask: Might those observed intermediate-order g modes be stochastically excited? By employing a statistical method which searches for the signature of stochastic excitation in stellar pulsations, we investigate the nature of those modes with possible implications on the identification of their excitation mechanism. Preliminary results are rather inconclusive about the presence of stochastic excitation. A new analysis that thoroughly takes into account sampling effects is necessary in order to get more reliable results., Comment: 4 pages, 3 figures, submitted to Astronomische Nachrichten, to appear in the proceedings of the IV HELAS International Conference

Published
2010

25. Kepler observations of Am stars

Author

Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., Girouard, F. R., Balona, L. A., Ripepi, V., Catanzaro, G., Kurtz, D. W., Smalley, B., De Cat, P., Eyer, L., Grigahcène, A., Leccia, S., Southworth, J., Uytterhoeven, K., Van Winckel, H., Christensen-Dalsgaard, J., Kjeldsen, H., Caldwell, D. A., Van Cleve, J., and Girouard, F. R.

Abstract

We present an analysis of high-resolution spectra for two pulsating Am stars in the Kepler field. The stellar parameters derived in this way are important because parameters derived from narrow-band photometry may be affected by the strong metal lines in these stars. We analyse the Kepler time series of ten known Am stars and find that six of them clearly show δ Scuti pulsations. The other four appear to be non-pulsating. We derive fundamental parameters for all known pulsating Am stars from ground-based observations and also for the Kepler Am stars to investigate the location of the instability strip for pulsating Am stars. We find that there is not much difference between the Am-star instability strip and the δ Scuti instability strip. We find that the observed location of pulsating Am stars in the HR diagram does not agree with the location predicted from diffusion calculations

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