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FUSE Spectroscopy of Cool Stars

FUSE Spectroscopy of Cool Stars. Graham Harper CASA, University of Colorado. Far Ultraviolet Spectroscopic Explorer. FUSE USA with France and Canada as partners FUSE Launched June 24, 1999. 765 km circular orbit, inclined 25 degrees, P = 100 minutes. 5-yr in orbit

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FUSE Spectroscopy of Cool Stars

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  1. FUSE Spectroscopy of Cool Stars Graham Harper CASA, University of Colorado Cool Stars 13, Hamburg 2004

  2. Far Ultraviolet Spectroscopic Explorer • FUSE • USA with France and Canada as partners • FUSE Launched June 24, 1999. • 765 km circular orbit, inclined 25 degrees, P = 100 minutes. • 5-yr in orbit • 3-yr Primary Mission ended Mar. 2003. • Now all Guest Investigator (GI) . • Approx. 9 Msec/yr of science observations; ~ 600 objects/yr. • 30% orbital efficiency for science observations Cool Stars 13, Hamburg 2004

  3. Far Ultraviolet Spectroscopic Explorer • 905Å < λ < 1187Å • Resolution ~ 15 kms-1 • Three Apertures • LWRS 30x30" • MDRS 4x20" • HIRS 1.25x20" • Pointing ~ 0.5" • FWHM ~ 1" @ 1000Å Cool Stars 13, Hamburg 2004

  4. FUV Spectral Diagnostics Cool Stars 13, Hamburg 2004

  5. α TrA Hybrid chromosphere star Cool Stars 13, Hamburg 2004

  6. Luminous Cool Stars • A. Dupree kindly provided a figure from the Cool star PI team – from a paper in progress (not shown here) • Fig. showed how the spectra are typically a combination of solar-like transition region lines and Fe II fluorescence • Fig. showed discovery of O VI (a coronal proxy) in αTau, and the Fe XVIII emission

  7. Hyades F dwarfs – touching the corona? • Böhm-Vitense, Robinson, & Carpenter (2004 ApJ 606, 1174) • Determine whether 300000 K plasma • is heated by conduction from corona • or the same heating that controls lower Te • O VI & CIII 977Å compared with IUE/HST and ROSAT • B-V and vsini trends for O VI very different from X-rays • Conclude heating Te < 300,000 K not dominated by conduction from corona Cool Stars 13, Hamburg 2004

  8. Convective/Radiative Boundary • Simon et al. (2002 ApJ 579, 800) • Search for FUV emission in A stars • Follow up of ORFEUS-SPAS II αCephei (A7 V) Cool Stars 13, Hamburg 2004

  9. Convective/Radiative Boundary Cool Stars 13, Hamburg 2004

  10. Convective/Radiative Boundary Cool Stars 13, Hamburg 2004

  11. Convective/Radiative Boundary • Simon et al. (2002 ApJ 579, 800) • Search for FUV emission in A stars • Teff < 8200 K: solar-like normalized fluxes • Teff > 8300 K: non-detections <1/40th solar • Transition from convective to radiative envelope occurs near 8250 K in agreement with structure models Cool Stars 13, Hamburg 2004

  12. A-F Supergiants: Blue loop activity • Brown provided a figure showing the OVI region for a sample of A-F supergiants. These stars are consistent with blue-loop activity. • The OVI is clearly detected in the A8 Ib star • This work will be presented at the • “Astrophysics in the Far Ultraviolet” Five Years of Discovery with FUSE – Victoria, BC August 2-6, 2004

  13. Electron Pressure/Opacity Diagnostics Cool Stars 13, Hamburg 2004

  14. C III Electron Pressure Diagnostics • Do not abandon hope! • Samples of disk integrated fluxes • CIII 1175/977Å • Guinan et al. (2003 ApJ 594, 561) • Sun-in-Time – snap-shots of Pe • Combine DEM or proxy • Ionization balance • 1175.98Å relative to Σ1175Å

  15. Optical Depth Effects • 1175Å AU Mic Bloomfield et al. (2002 A&A 390, 219) • 1175.71Å & 1174.94Å share common upper-level J=2 • Ratio changes during flare • Low gravity stars: opacity effects play a larger role

  16. FUV Coronal Forbidden Lines • Feldman et al. (2000 ApJ 544, 508) • HST Fe XXI 1354Å • Blended with C I • HST Fe XII 1242,1349Å • Jordan et al. (2001 MNRAS 322, L5) • Redfield et al. (2003 ApJ 585, 993) • FUSE Fe XVIII 974Å (clean) • FUSE Fe XIX 1118Å (blend C I) • Thermally broadened lines • Plasma is not part of the wind Cool Stars 13, Hamburg 2004

  17. Fe XVIII & Fe XIV Cool Stars 13, Hamburg 2004

  18. Extended Coronal Rotation? • Excess broadening • Beyond thermal + vsini • Consistent ΔR~0.4-1.3R∗ • OR excess turbulence Cool Stars 13, Hamburg 2004

  19. Fluorescence • Probe of intrinsic HI Lyα profile • Before attenuation by ISM • Before attenuation by wind • FUSE & HST • Fe II • H2 Cool Stars 13, Hamburg 2004

  20. Fluorescence: HLyα & Fe II Cool Stars 13, Hamburg 2004

  21. Fluorescence: Mira B - HLyα & H2 • Mira A&B- Wood & Karovska (2004 ApJ 601 502) • HST Lyman band lines • FUSE reveals Werner band lines Cool Stars 13, Hamburg 2004

  22. Fluorescence: Mira B - HLyα & H2 Cool Stars 13, Hamburg 2004

  23. Fluorescence: Mira B - HLyα & H2 • Mira A&B - Wood & Karovska (2004 ApJ 601 502) • HST Lyman band lines • FUSE reveals Werner band lines • Reconstructed Lyα • T=3900 K & LogN(H2)=17.1 • Photodissociation front • Mira B H Lyα interacts • Mira A’s wind Cool Stars 13, Hamburg 2004

  24. FUSE Status • Gyroless software installed and tested • July 2003 worked seamlessly – no loss of science • 4 operational gyros – currently in 2 gyro mode • Allow for fast response of TOO • CalFUSE v3.0.7: public release 15th July 2004 • New photon list data structure • Allows for more efficient screening of data • 2 reaction wheels + magnetic torquer bar • Sky availability recently expanded • Cycle 6 proposal deadline Sept 17th 2004 Cool Stars 13, Hamburg 2004

  25. That’s All Folks … • Other CS13 FUSE Presentations • Talks • Cian Crowley – Wind Velocity Laws of Symbiotics • Posters • Thomas Ake – Eclipsing Binaries • Brian Espey – Mass Loss from Symbiotics Cool Stars 13, Hamburg 2004

  26. Pre-mainsequence & Protoplanetary Systems • T Tauri • TW Hya - Herczeg et al. (2004 ApJ 607, 369) • Herbig AeBe • HD 104237 - Grady et al. (2004 ApJ 608, 809) • Lecavelier des Etangs et al. (2003 A&A 407, 935) • HD 100546 - Deleuil et al. (2004 A&A 418, 577) • βPic systems • Bouret et al. (2002 A&A 390, 1049) Cool Stars 13, Hamburg 2004

  27. Thanks to • George Sonneborn: FUSE Project Scientist • Bill Blair: FUSE Chief of Observatory Operations • All and Sundry for discussions and kindly providing figures Cool Stars 13, Hamburg 2004

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