Cool Stars 13, Hamburg 2004

FUSE Spectroscopy of Cool Stars

Graham HarperCASA, University of Colorado

Cool Stars 13, Hamburg 2004

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

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

FUV Spectral Diagnostics

Cool Stars 13, Hamburg 2004

α TrA Hybrid chromosphere star

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 α Tau, and the Fe XVIII emission

Cool Stars 13, Hamburg 2004

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

Convective/Radiative Boundary

Simon et al. (2002 ApJ 579, 800) Search for FUV emission in A stars Follow up of ORFEUS-SPAS II α Cephei (A7 V)

Cool Stars 13, Hamburg 2004

Convective/Radiative Boundary

Cool Stars 13, Hamburg 2004

Convective/Radiative Boundary

Cool Stars 13, Hamburg 2004

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

A-F Supergiants: Blue loop activity

A. Brown provided a figure showing the OVI region for a sample of A-F supergiants. These stars are consistent with blue-loop activity.

B. The OVI is clearly detected in the A8 Ib starC. This work will be presented at the D. “Astrophysics in the Far Ultraviolet” Five Years of

Discovery with FUSE – Victoria, BC August 2-6, 2004

Cool Stars 13, Hamburg 2004

Electron Pressure/Opacity Diagnostics

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

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

Cool Stars 13, Hamburg 2004

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

Fe XVIII & Fe XIV

Cool Stars 13, Hamburg 2004

Extended Coronal Rotation?

Excess broadening Beyond thermal + vsini Consistent ΔR~0.4-1.3R∗

OR excess turbulence

Cool Stars 13, Hamburg 2004

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

Fluorescence: HLyα & Fe II

Cool Stars 13, Hamburg 2004

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

Fluorescence: Mira B - HLyα & H2

Cool Stars 13, Hamburg 2004

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

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

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

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

Thanks to

George Sonneborn: FUSE Project Scientist Bill Blair: FUSE Chief of Observatory

Operations All and Sundry

for discussions and kindly providing figures