Nonlinear Pulsation Driven by Strange Modes in Hydrodynamic Models

Publications of the Astronomical Society of Japan

Sreenivasan, S. Ranga¹  Aikawa, Toshiki² 

[1] Department of Physics & Astronomy, The University of Calgary, Calgary, T2N IN4, Canada;Tohoku Gakuin University, Faculty of Liberal Arts, Sendai, Miyagi 981-31 E-mail:

关键词: Hydrodynamics;    instabilities;    "Stars: pulsation";   

DOI  :  10.1093/pasj/48.1.29

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Thecharacteristicsofthenonlinearpulsationofhydrodynamicmodels,whichhaveonlystrangemodesaspulsationalunstablemodes,arecomparedwiththosebyconventionalmodes.Itisshownthatnonlinearpulsationwiththestrangemodeshasconsiderableamplitudesonlyatthehydrogenionizationzoneandintheatmosphere.Thisissharpincontrasttothatbyconventionalmodes,andisidenticalwiththecharacteristicsoftheunstablelinearstrangemodes.Wethusconcludethattheunstablestrangemodesmayberesponsibleforthenonlinearpulsation.Wealsodiscussthephysicaloriginoftheinstabilityofthestrangemodes.Sincethemodesarepulsationallyunstablewithoutanyluminosityperturbation,otherphysicalmechanismsmustbeinvolvedfortheinstabilityalongwiththeconventionalkappaandgammamechanisms,whicharefamiliarinCepheidvariables.WesuggestthatthedensityinversionintheHionizationregion,includingtheadjacentHeIionizationzone,maybetheorigin.Finally,wesuggestthatthedifferentpulsationdrivingzonesmaycausethefeatureofthespatialamplitudevariations.

【 授权许可】

Unknown