X-Ray Emission-Line Profiles of Three Early-Type Stars Observed with Chandra

摘要

WeanalyzedtheX-rayemission-lineprofilesofthreeearly-typestars($$zeta$$Pup,$$delta$$Ori,and$$ au$$Sco)obtainedwithChandra.Aphenomenologicalmodel,whereX-raysourcesaredistributinginwindabovesomelowerlimitradius,canfitthelineprofilesof$$zeta$$Pupand$$delta$$Ori;however,thefittingrequiresamuchsmallerabsorptionthanexpectedfromthemass-lossrate.Thissuggeststhat,ifthisphenomenologicalmodelrepresentstherealX-rayemissionregion,thereissubstantialionizationorclumpingofthestellarwind.Theparametersderivedfromthelineprofileof$$ au$$ScoindicatethattheX-ray-emittingplasmaisconcentratedonthestellarsurface,suggestingtheexistenceofaconfinedplasmaonthestellarsurface.