stellar coronae and star formation with xeus -...
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StellarcoronaeandstarformationwithXEUS
BeateStelzer(OAPalermo)
contributionsfromL.Scelsi,
S.Sciortino
Aquicktourofobservablesfrompre‐MStoMSages
AdaptedfromFeigelson&Montmerle,ARA&A,1999
X‐RAYSINCLASS0VERYCONTROVERSIAL
X‐RAYSINCLASSII(1)TRACEACCRETION(SHOCKS)(2)IONIZATIONAGENTOFDISK
X‐RAYSINCLASSIIIIDENTIFYLATEPre‐MSSTARS(CORONA)
X‐RAYSINMSCORONALSTRUCTURE
X‐RAYSINCLASSIJETS(SHOCKSINOUTFLOWS)
+X‐RAYSFROMHOTSTARS
+X‐RAYSFROMBROWNDWARFS
Need
moresensitivehighspatialresolutionhighspectralresolution
X‐rayobservations
CLASS0:X‐rays?Needhighsensitivity+highspatialresolution
Giardinoetal.(2007)
Co‐addedACISimagefrom6Class0intoeffective540ksexposure:
Assume:NH=41023cm‐2,kT=2.4keVLx<41029erg/s
Class0fainterX‐raysthanClassI,II,IIIorextremeextinction
Serpensstarformingregion:Spitzer/IRAC1imagewithChandra/ACISfield
XEUS/WFI:Llim~41029erg/sforNH=1024cm‐2
in~10ks@260pc
Protostellarandpre‐MSjets:Needhighspatialresolution+highsensitivity
LaValleyetal.(1997)
[OI]6300A
Smoothed Color‐coded
0.6‐1.7keVACIS‐S:DGTau+jets
Guedeletal.(2008)
4”
4X‐rayemittersinDGTausystem:
• soft,weaklyabsorbedjet• soft,strongerabsorbedcounterjet• soft,weaklyabsorbedbaseofforwardjet• hardstellarcorona
Guedeletal.(2008)
UnfeasiblewithXMM!
Smoothed Color‐coded
0.6‐1.7keVACIS‐S:DGTau+jets
Guedeletal.(2008)
4”
Protostellarandpre‐MSjets:Needhighspatialresolution+highsensitivity
4X‐rayemittersinDGTausystem:
• soft,weaklyabsorbedjet• soft,strongerabsorbedcounterjet• soft,weaklyabsorbedbaseofforwardjet• hardstellarcorona
Guedeletal.(2008)
Diskgas‐to‐dustratiofromdifferentialextinctionofjet+counterjetbut9countsfromcounter‐jetin90ksecChandra
Smoothed Color‐coded
0.6‐1.7keVACIS‐S:DGTau+jets
Guedeletal.(2008)
4”
Protostellarandpre‐MSjets:Needhighspatialresolution+highsensitivity
CLASSII:accretionvs.magneticactivityNeedhighspectralresolution+highsensitivity
• Diagnosticforaccretionshock:high‐density(~1012cm‐3)(vs.low‐densitycorona)
linediagnostics,He‐liketriplets
• fewcTTSbrightenoughforXMM/Chandragratings
TWHyaGuentheretal.(2007)
RGSNeIXtriplet(corona+shock)
CLASSII:accretionvs.magneticactivityNeedhighspectralresolution+highsensitivity
Schmittetal.(2005)
130ksXMM/RGS
lowf/iratiohighdensity:31011cm‐3
(notconsideringUVradiationandcoronalcontribution)
100ksXEUS/TES
CLASSII:accretionvs.magneticactivityNeedhighspectralresolution+highsensitivity
Schmittetal.(2005)
130ksXMM/RGS
lowf/iratiohighdensity:31011cm‐3
(notconsideringUVradiationandcoronalcontribution)
100ksXEUS/TES
Tripletsofhigh‐energyelementsrepresentcoronane=f(T)
HR9024(Ggiant)–Testietal.(2008)
6.4keVKα lineduringinitialphaseofflare
photosphericfluorescencemodelconstrainsflareheight:~0.1R*
FeKαemission:fluorescenceore‐impactionization?
Elias29(ClassIprotostarinOph)‐‐Giardinoetal.(2007):
6.4keVΚα lineinquiescentphaseafteraflare
sustainedionizationmechanismindependentofX‐rays;coll.Ionizationbynon‐thermalelectronsinstar‐diskloops
FeKFeXXV
HR9024(Ggiant)–Testietal.(2008)
6.4keVKα lineduringinitialphaseofflare
photosphericfluorescencemodelconstrainsflareheight:~0.1R*
FeKαemission:fluorescenceore‐impactionization?
Elias29(ClassIprotostarinOph)‐‐Giardinoetal.(2007):
6.4keVΚα lineinquiescentphaseafteraflare
sustainedionizationmechanismindependentofX‐rays;coll.Ionizationbynon‐thermalelectronsinstar‐diskloops
FeKFeXXV
FeKemissionwithXEUS/WFI
Highsensitivity,highspectralresolution,largefield‐of‐view
detectionofFeKαinlargesampleofstarsindifferentevolutionphases
equiv.width>50Ådetectablein15ks(photosphere)
Constraingeometryby(A)modelingphotosphericfluorescenceefficiency(B)detectingtime‐delaybetweenflareandappearanceofFeKlinefordisk‐fluorescence
85ksXMM/pn 15ksXEUS/WFI
Giardinoetal.(2007)
W=250ÅFeKα
FeXXV
MSstars:CoronalmappingNeedhighsensitivity
Hussainetal.(2005)
RotationalmodulationofX‐rayemissiononnearbyflarestarABDorinhomogeneousdistributionofX‐rayemittingmaterial?
Prot~0.5d
MSstars:CoronalmappingNeedhighsensitivity
Hussainetal.(2007)
OVIII
=0.3 =0.8
spotmapExtrapolationofsurfacefieldtocoronamodelingofX‐rayemittingloopsreconstructionofX‐raylightcurve
RESULTS:nopolarityreversalbetweenthetwohemispheresforABDor
Flarephysics:plasmaevolutioninrisephaseNeedhighsensitivityfortime‐resolvedspectroscopy
Stelzeretal.(2006)
LP412‐31:simultaneousopt/X‐rayflarewithXMM
Fastopticalevent:V = 6 magin40sec
Δtopt./X‐raypeak<20sec
Time‐resolvedspectroscopy…HDmodelofflaredecayheating,looplengthFILLLONGLOOPINSHORTTIMEI.E.HIGHVELOCITY(LINESHIFT)
…inflarerise?
Flarephysics:plasmaevolutioninrisephaseNeedhighsensitivityfortime‐resolvedspectroscopy
Schmittetal.(2008)
Time‐resolvedspectroscopy…HDmodelofflaredecayheating,looplengthFILLLONGLOOPINSHORTTIMEI.E.HIGHVELOCITY(LINESHIFT)
…inflarerise?
PotentialofXEUSstellarstudies
• derivecompletePre‐MSpopulation(togetherwithIR)invariousenvironmentsIMF,diskfraction,…
• trace+distinguishhotplasmafromvariousphysicalprocesses:magneticactivity,accretionandwinds
• coronalstructure(fieldmapping,flareanalysis)
• roleofX‐raysforstarformationbyionizingcircumstellardisks+facilitatingaccretion
• X‐raysfromhotstarswindclumping,masslossrates,…
• X‐raysfrombrowndwarfsdynamosinsub‐stellarobjects
Hotstars:linebroadening(winds)Needhighspectralresolution+highsensitivity
Broad
Narrow
1kev2.5kev 0.48kev
XEUSBETTER(2eV)@EqualStatistics
Oskinovaetal.(2005)
Hotstars:linebroadening(winds)Needhighspectralresolution+highsensitivity
Cassinellietal.(2001)
(A)asymmetric,blue‐shiftedlines
highopticaldepth
Oskinovaetal.(2005)
(B)symmetric,lines
transparentwind
Hotstars:OriginofX‐rays?Needhighspectralresolution+highsensitivity
1 OriConlyhotstarwithrisingDEM
Wojdowski&Schulz(2005)
Gagneetal.(2005)
X‐raysfrommagn.Confinedwind
Weaklyabsorbed,softBDinONC
Lx=1027erg/s@450pc
fx=410‐17erg/cm2/s
(fx)abs=110‐17erg/cm2/[email protected]‐2keVforNH=21022cm‐2(Av=10mag)kT=1keVin100ksecwithXEUS
BrowndwarfswithXEUS
Preibischetal.(2005)