a.l obel sao funding spatially r rr resolved stis s ss spectroscopy o oo of betelgeuse’s u pper c...
Post on 20-Dec-2015
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A.A. Lobel SAO fundingLobel SAO funding
SpatiallySpatially Resolved Resolved STISSTIS SpectroscopySpectroscopy ofof
Betelgeuse’sBetelgeuse’s UpperUpper Chromosphere and Chromosphere and Circumstellar Dust EnvelopeCircumstellar Dust Envelope
1000 mas
600 mas
400 mas
200 mas
126 mas63 masPeak-up Mg II k
Inner
Chromosphere
UpperChromosphere
2002-2003
Hinz et al. Nature 1998
4000 mas
1000 mas500 mas
HST-STIS near-UV spectra Upper chromosphere
2002-2003
Circumstellar Inner Dust Envelope MMT 9.8 m image
200 mas400 mas600 mas
0 mas
1000 mas
2000 mas3000 mas
IRAS ISO Dust emission
Input model SED Teff = 3500 K log(g) = - 0.5
DUSTY model best fit SED
9.8 = 0.015
0.05 m < grain size < 0.5 m Tdust = 600 K0.05 m < grain size < 0.5 m Tdust = 800 K1 m < grain size < 5 m Tdust = 600 K
Conclusions on Betelgeuse• Emission lines of upper chromosphere observed
far inside inner dust envelope to 3 arcseconds or ~120 R*
• First evidence of outward accelerating upper chromospheric wind from increasing emission line asymmetry
• Emission lines of upper chromosphere form at kinetic gas temperatures Tgas > 2600 K far inside inner Circumstellar Dust Envelope
• Ambient gas temperature in the CDE Tgas < 600 K required for dust formation
• Warm chromospheric gas and cool dusty gas co-exist far beyond dust condensation radius of dust-driven wind models
• New observations require wind driving physics sustaining warm and cool gas in upper chromosphere
• Evidence for shock wave propagation in the upper chromosphere?
• Outflow caused by radiation pressure onto dust at the inner chromosphere, or initiated by acoustic energy propagation from the photosphere?
Where do we go from here?