X-Ray Flares from a Late B-Type Star, HD 38563S, in NGC 2068 Observed with Chandra X-Ray Observatory

摘要

AreportismadeontheChandraarchivaldataanalysisofNGC2068,whichisoneofthenearest($$sim400,mathrm{pc}$$)andX-rayactivestar-formingregions,withanestimatedageof$$10^{5-6},mathrm{yr}$$.Theobservationwasmadefor100a€‰ks.Usingthewavdetecttool,152X-raysourcesweredetected,ofwhich52hadcounterpartsinthe2MASSsurvey.OneofthebrightestX-raysourcesisapparentlyidentifiedwitha$$V=10.42$$lateB-typemain-sequencestar,HD38563S.Duringtheobservation,itexhibitedtwoX-rayflares,withthe0.5a€“8.0a€‰keVluminosityreaching$$sim10^{31.6},mathrm{erg},mathrm{s}^{-1}$$.TheflareX-raysevolvedonatimescaleofseveralhours,andshowedathermalspectrumoftemperatureof$$sim5,mathrm{keV}$$.Theseresultssuggeststhatthisstarformsanactivebinary,althoughcontaminationbyaTTauristaralsoremainsanalternativepossibility.