Tidal-Force-Induced Precessions of Accretion Disks

Publications of the Astronomical Society of Japan

Inoue, Hajime¹ 

[1] Space Activities Commission, Ministry of Education, Culture, Sports, Science and Technology, 3-2-2 Kasumigaseki, Chiyoda-ku, Tokyo 100-8959

关键词: "accretion disks";    binaries;    "compact stars";    "X-rays: individual (Her X-1;    SS 433)";   

DOI  :  10.1093/pasj/64.2.40

学科分类：天文学(综合)

来源: Oxford University Press

【 摘 要 】

Thepreccessionofanaccretiondiskaroundacompactstarinaclosebinaryhasbeenstudied.Whentheaccretiondisktilts,thetidalforcefromthecompanionstarinducesatorqueonit,whichcausesapreccessionofthedisk.Wefirstlyconsiderthepropertiesofapreccessingmotionofaring,whichiscircularlyrotatingaroundacompactstar,andispreccessingwithaslightlytiltingangleundertheinfluenceofatidalforcefromacompanionstar.Wenextcomparethepredictedbehaviorsofthepreccessingringwithobservations,andfindthatseveralobservationalfactsfromHerX-1,SS433,andsomeotherX-raybinariescanbeexplainedbyatidal-force-inducedprecessionschemequitereasonably.Wefurtherexaminetheenergeticsofthepreccessingringasafunctionofthetiltingangle.Itisshownthatthekineticandpotentialenergiesoftheorbitingmotionsoftheringmatteraroundthecompactstarincreasesasthetiltingangleincreases,whilethethermalandeffectivepotentialenergiesforhydro-staticbalanceinthemeridiancrosssectionoftheringdecreasesthroughadiabaticexpansion.Quantitativeestimationshaveshownthatwhentheringhassufficientthermalenergy,thedecreaseoftheenergyforthehydro-staticbalancecanbelargerthantheincreaseoftheenergyforcircularmotionaroundthecompactstaruntilthetiltinganglereachesacertainvalue.Itisstronglysuggestedthatpreccessionsofaccretiondisksareoftenrealizedinclosebinaries.

【 授权许可】

Unknown