Winds in Symbiotic Red Giants: A Perspective from the Base of Outflow

CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008

Winds in Symbiotic Red Giants:Winds in Symbiotic Red Giants:A Perspective from the Base of OutflowA Perspective from the Base of Outflow

Cian CrowleySchool of Physics

Trinity College Dublin

Collaborators:Dr. Brian Espey, Joseph Roche Trinity College DublinDr. Stephan McCandliss Johns Hopkins University+ Phoenix contributors & more…


OutlineOutlineOutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection

Symbiotics?Symbiotics as probes of red giant winds

Overview of ResultsWind / Chromosphere conditions,

parametersCaveats?

Binarity affecting results?Project Direction

Chromospheric modellingPhotospheric conditions

HST cycle 17 data


Symbiotic Systems

White Dwarf as a UV search light to probe RG wind in absorption

Binary Systems Containing: - Red Giant Primary (usually M) - White Dwarf Secondary

FUSE + HST/STIS data for 4 objects.... (see Espey poster, M3)...also echelle optical data

OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection


Example of STIS data:non-eclipsed + eclipsed + Absorption Model (blue)

FeII Contribution to fit

Contribution of HI + SiII, PII, TiII etc.



EG And absorption spectrum

Absorption lines from species such as CII, NI, OI, MgII, SiII, PII, ArI, MnII, FeII, NiII….etc. (no cool or hot bubbles detected)

Transitions observed from range of lower energy levels: absorption from 0 to 4.5ev above ground

Over 2.2 < RRG < 3.7 populated Fe+ levels imply 6,500 K < T < 8,500 K

Wind/chromosphere ‘clumpy’; sizes < 1% RRG

Wind velocity differs from Beta-law in EG And & SY Mus



BF Cyg Absorption• M5 giant, Higher mass-loss rate (~4 - 5 times)• Wind probed further out (~4 - 6.5 RRG)

• Similar excitation+ionisation (Texcite~6 - 8000K)• WD more luminous, but, Mass-loss higherionised

region confined close to WD similar to EG And



Caveats?Caveats?

Effect of Binarity on the wind?Effect of WD radiatively, gravitationally,

mechanically?

•Optical spectra show atmosphere unperturbed •Ionised zone confined close to WD (Cloudy

models)•Absorption line profiles symmetric

But…Eclipsing systems produce higher mass-loss rates

& wind velocities material deflected onto orbital plane?

Confident that chromos/inner wind diagnostics representitive of isolated stars!



Project Project DirectionDirection


Phoenix chromospheric modelingModels need to show sharp temperature rise

above photosphere match plateau at ~8,000 K as observed

Photospheric conditionsConvective motions asymmetries in line profiles (see poster of Joe Roche, M11)

Also evolutionary status etc. from abundance study

HST cycle 174 extra observations of EG And:

Will tie down wind accel. shape, probe ‘clumpyness’ & test for wind variability, also 2

standards to be observed


Questions…?Questions…?

Crowley, Espey & McCandliss, 2008, ApJ, 675, 711-722

Separate papers on detailed EG And wind modeling & BF Cyg wind in prep.


Topics for Discussion… To increase rate of progress To increase rate of progress more more

communication between members in communication between members in field…field…

TCD group propose hosting webpage TCD group propose hosting webpage summarising session, active topics for work summarising session, active topics for work & repository for models, spectra etc. & repository for models, spectra etc. would be a central archive to be updated would be a central archive to be updated

Identify points for discussion & areas for Identify points for discussion & areas for work….. work…..


Topics for Discussion…

Identify targets for models & for future Identify targets for models & for future observations observations i.e., list binary giants (+ isolated proxy stars) that i.e., list binary giants (+ isolated proxy stars) that

should be modelled in detail should be modelled in detail list on webpage list on webpage (along with data + parameters, quick reference (along with data + parameters, quick reference for future proposals, model params) for future proposals, model params)

Need more optical data for binary objects? Basic Need more optical data for binary objects? Basic photospheric params? vsin(i) values?photospheric params? vsin(i) values?

Thermodynamic models publicly available Thermodynamic models publicly available i.e., can quickly compare to data, can i.e., can quickly compare to data, can produce radio models (Graham)produce radio models (Graham)


Topics for Discussion (biased!)…

Conditions at photosphere: diagnose/model Conditions at photosphere: diagnose/model convective activity (low-mass models?)convective activity (low-mass models?)

Conditions in Chromosphere/inner wind: plateau Conditions in Chromosphere/inner wind: plateau ~8,000K? Chromos separate from wind? ~8,000K? Chromos separate from wind? Structure? (neutral medium models?)Structure? (neutral medium models?)

Wind accel profile: Delayed (static chromos)? Wind accel profile: Delayed (static chromos)? Shallow? Shallow?

Scaling to supergiants? Scaling to supergiants? same v(r)? same v(r)?

Winds in Symbiotic Red Giants: A Perspective from the Base of Outflow

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