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97 results on '"Althaus L"'

16. Asteroseismology of hybrid δ Scuti-γ Doradus pulsating stars.

Author

Sánchez^Arias, J. P., Córsico, A. H., and Althaus, L. G.

Subjects
PULSATING stars, VARIABLE stars, STELLAR oscillations, STELLAR evolution, INSTABILITY strip (Astrophysics)
Abstract

Context. Hybrid δ Scuti-γ Doradus pulsating stars show acoustic (p) oscillation modes typical of γ Scuti variable stars, and gravity (g) pulsation modes characteristic of Doradus variable stars simultaneously excited. Observations from space missions such as MOST, CoRoT, and Kepler have revealed a large number of hybrid δ Scuti-γDoradus pulsators, thus paving the way for an exciting new channel of asteroseismic studies. Aims. We perform detailed asteroseismological modelling of five hybrid δ Scuti-γDoradus stars. Methods. A grid-based modeling approach was employed to sound the internal structure of the target stars using stellar models ranging from the zero-age main sequence to the terminal-age main sequence, varying parameters such as stellar mass, effective temperature, metallicity and core overshooting. Their adiabatic radial (l = 0) and non-radial (l = 1; 2; 3) p and g mode periods were computed. Two model-fitting procedures were used to search for asteroseismological models that best reproduce the observed pulsation spectra of each target star. Results. We derive the fundamental parameters and the evolutionary status of five hybrid δ Scuti-γDoradus variable stars recently observed by the CoRoT and Kepler space missions: CoRoT 105733033, CoRoT 100866999, KIC 11145123, KIC 9244992, and HD 49434. The asteroseismological model for each star results from different criteria of model selection, in which we take full advantage of the richness of periods that characterises the pulsation spectra for this kind of star. [ABSTRACT FROM AUTHOR]

Published
2017
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34. The pulsation modes of the pre-white dwarf PG 1159-035

Author

Costa, J. E. S., primary, Kepler, S. O., additional, Winget, D. E., additional, O'Brien, M. S., additional, Kawaler, S. D., additional, Costa, A. F. M., additional, Giovannini, O., additional, Kanaan, A., additional, Mukadam, A. S., additional, Mullally, F., additional, Nitta, A., additional, Provençal, J. L., additional, Shipman, H., additional, Wood, M. A., additional, Ahrens, T. J., additional, Grauer, A., additional, Kilic, M., additional, Bradley, P. A., additional, Sekiguchi, K., additional, Crowe, R., additional, Jiang, X. J., additional, Sullivan, D., additional, Sullivan, T., additional, Rosen, R., additional, Clemens, J. C., additional, Janulis, R., additional, O'Donoghue, D., additional, Ogloza, W., additional, Baran, A., additional, Silvotti, R., additional, Marinoni, S., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Dreizler, S., additional, Schuh, S., additional, Deetjen, J., additional, Nagel, T., additional, Solheim, J.-E., additional, Gonzalez Perez, J. M., additional, Ulla, A., additional, Barstow, M., additional, Burleigh, M., additional, Good, S., additional, Metcalfe, T. S., additional, Kim, S.-L., additional, Lee, H., additional, Sergeev, A., additional, Akan, M. C., additional, Çakırlı, Ö., additional, Paparo, M., additional, Viraghalmy, G., additional, Ashoka, B. N., additional, Handler, G., additional, Hürkal, Ö., additional, Johannessen, F., additional, Kleinman, S. J., additional, Kalytis, R., additional, Krzesinski, J., additional, Klumpe, E., additional, Larrison, J., additional, Lawrence, T., additional, Meištas, E., additional, Martinez, P., additional, Nather, R. E., additional, Fu, J.-N., additional, Pakštienė, E., additional, Romero-Colmenero, E., additional, Riddle, R., additional, Seetha, S., additional, Silvestri, N. M., additional, Vučković, M., additional, Warner, B., additional, Zola, S., additional, Althaus, L. G., additional, Córsico, A. H., additional, and Montgomery, M. H., additional

Published
2007
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49. Pulsations driven by the ϵ-mechanism in post-merger remnants: First results.

Author

Miller Bertolami, M. M., Córsico, A. H., Zhang, X., Althaus, L. G., and Jeffery, C. S.

Subjects
STELLAR oscillations, DWARF stars, HELIUM, GALAXIES, ASTRONOMY
Abstract

Helium-rich subdwarfs are a rare subclass of hot subdwarf stars which constitute a small and inhomogeneous group showing varying degrees of helium enrichment. Only one star, LS IV °14 116 has been found to show multiperiodic luminosity variations. The variability of LS IV °14 116 has been explained as the consequence of nonradial g-mode oscillations, whose excitation is difficult to understand within the frame of the standard κ-mechanism driving pulsations in sdBV stars. In a recent study, we have proposed that the pulsations of LS IV °14 116 might be driven through the ϵ-mechanism acting in unstable Heburning zones in the interior of the star, that appear before the quiescent He-burning phase. One of the few accepted scenarios for the formation of He-rich subdwarfs is the merger of two He-core white dwarfs. As part of this project, we present a study of the ϵ-mechanism in post-merger remnants, and discuss the results in the light of the pulsations exhibited by LS IV °14 116. [ABSTRACT FROM AUTHOR]

Published
2013
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