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…
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
Example of STIS data:non-eclipsed + eclipsed + Absorption Model (blue)
FeII Contribution to fit
Contribution of HI + SiII, PII, TiII etc.
OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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
OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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
OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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!
OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?Project Project DirectionDirection
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
Project Project DirectionDirection
OutlineOutlineSymbioticsSymbioticsResultsResultsCaveats?Caveats?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
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
Questions…?Questions…?
Crowley, Espey & McCandliss, 2008, ApJ, 675, 711-722
Separate papers on detailed EG And wind modeling & BF Cyg wind in prep.
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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…..
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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)
CS15 St. Andrews, July 2008CS15 St. Andrews, July 2008
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)?