A Wind Analysis of an Evolved Giant Phase Resolved FUSE and HST/STIS Observations of an Eclipsing Symbiotic Binary Cian Crowley Dr. Brian Espey Trinity College Dublin Collaborators: McCandliss, Ferland, Lamers, Hauschildt, Barman, Keenan, Young Cool Stars Hamburg

What are symbiotic binaries? Binary nature confirmed by IUE Binary nature confirmed by IUE Red giant continuum with emission lines requiring photoionisation by UV source Red giant continuum with emission lines requiring photoionisation by UV source red giant primary red giant primary white dwarf secondary white dwarf secondary line emission from ionised portion of RG wind line emission from ionised portion of RG wind Closest separation detached binaries Closest separation detached binaries

Composite symbiotic spectrum Need multiwavelength data

System parameters EG And has a number of important properties: EG And has a number of important properties: Non-dusty, low extinction Non-dusty, low extinction Low luminosity WD secondary Low luminosity WD secondary Bright from optical into far-UV Bright from optical into far-UV Eclipsing binary Eclipsing binary Well determined orbit ~ 481 days Well determined orbit ~ 481 days Never observed to undergo outburst Never observed to undergo outburst

EG And…..some numbers: Separation ~ 4.5 R RG Separation ~ 4.5 R RG Inclination > 70º (from eclipses) Inclination > 70º (from eclipses) RG: Spectral type: M3 – T eff : ~ 3,700K Luminosity: ~ 950L  Mass loss ~ few x 10 –8 M  yr –1 R RG ~ 75 R  WD: T eff ~ 75,000K Luminosity ~ 30L 

Dataset Ground-based high resolution echelle spectra (R ~ 35,000) Ground-based high resolution echelle spectra (R ~ 35,000) Far-Ultraviolet Spectroscopic Explorer (FUSE) data for 912 – 1180 Ångstrom region (R ~ 15,000 – 20,000) Far-Ultraviolet Spectroscopic Explorer (FUSE) data for 912 – 1180 Ångstrom region (R ~ 15,000 – 20,000) Hubble Space Telescope (HST) medium resolution echelle spectra for 1150 – 3180 Ångstrom region (R ~ 48,000) Hubble Space Telescope (HST) medium resolution echelle spectra for 1150 – 3180 Ångstrom region (R ~ 48,000)

HST data covering 1150 – 5600 Å

Absorption lines in the UV / FUV Incorrect or incomplete atomic data in FUV Incorrect or incomplete atomic data in FUV Spectral region extremely feature rich Spectral region extremely feature rich But complications as always…. Absorption data provides tomographic information on the chromosphere / low wind of the giant star Absorption data provides tomographic information on the chromosphere / low wind of the giant star HI columns well defined by Lyman alpha damping profile HI columns well defined by Lyman alpha damping profile – blending and saturated lines complicate analysis – blending and saturated lines complicate analysis

Observed wavelength Flux Phi=0.90Phi=0.04Phi=0.15Phi=0.80

Wind conditions Absorption lines from species such as CI, CII, NI, NII, OI, OII, MgII, AlII, SiII, PII, ArI, CaII, MnII, FeII, CoII, NiII…. Absorption lines from species such as CI, CII, NI, NII, OI, OII, MgII, AlII, SiII, PII, ArI, CaII, MnII, FeII, CoII, NiII…. Transitions observed from range of lower energy levels: absorption from 0 to 4.5ev above ground Transitions observed from range of lower energy levels: absorption from 0 to 4.5ev above ground However no CO or H 2 absorption in chromosphere H 2 /H tot < 10 –8 However no CO or H 2 absorption in chromosphere H 2 /H tot < 10 –8 Populations of FeII levels reveal temp ~ 8,000K Populations of FeII levels reveal temp ~ 8,000K Ionisation level constant through ingress and egress Ionisation level constant through ingress and egress

Wind velocity profiles……

Standard wind model The standard parameterisation of winds from both hot and cool stars is a beta law model: The standard parameterisation of winds from both hot and cool stars is a beta law model: v(r) = v  (1– R/r)  The following ranges of  are found: The following ranges of  are found: 0.5    1 hot stars (Lamers & Morton 1981) 2.5    3.5 K supergiants (Schroeder 1985)

Onset of ionisation  Observed column densities (red points) and smooth polynomial model fit (black line)

Determination of wind parameters Data fit with a low order polynomial and this function is inverted Data fit with a low order polynomial and this function is inverted Solving the velocity / column density equation is a form of Abel inverse problem to which a solution has been found by Knill, Dgani and Vogel (1993) Solving the velocity / column density equation is a form of Abel inverse problem to which a solution has been found by Knill, Dgani and Vogel (1993)

Hot stars  EG And SY Mus

Further wind determinations… The spectra show similarities to the EG And data, but with stronger P-Cygni profiles The spectra show similarities to the EG And data, but with stronger P-Cygni profiles We have additional new FUSE data for BF Cyg (M5 III ) We have additional new FUSE data for BF Cyg (M5 III ) Clues to wind driving mechanism? Clues to wind driving mechanism?

Summary Determination of wind conditions and acceleration for EG And Determination of wind conditions and acceleration for EG And Stellar models being generated for giant Stellar models being generated for giant Further data for other stars under analysis Further data for other stars under analysis Improved treatment of absorption lines (including improved atomic data) underway Improved treatment of absorption lines (including improved atomic data) underway Improved treatment of matter distribution (hydro code + photoionisation) planned Improved treatment of matter distribution (hydro code + photoionisation) planned

See poster: Brian Espey et al. : (Section F.1) ‘Multiwavelength observations of giant mass loss and interaction in eclipsing symbiotic binaries’ We acknowledge support from Enterprise Ireland Basic Research grant SC/2002/370 from EU funded NDP