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Pinpointing a stellar X-ray flare using XMM-Newton and VLT/UVES

Pinpointing a stellar X-ray flare using XMM-Newton and VLT/UVES. J.U. Ness J. Robrade J.H.M.M. Schmitt. Uwe Wolter Hamburger Sternwarte May 2008. 2006 October 14. 2006 October 15. Speedy Mic‘s rotation. XMM orbit 1254. VLT visibility. XMM observations.

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Pinpointing a stellar X-ray flare using XMM-Newton and VLT/UVES

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  1. Pinpointing a stellar X-ray flare using XMM-Newton and VLT/UVES J.U.Ness J.Robrade J.H.M.M.Schmitt Uwe Wolter Hamburger Sternwarte May 2008

  2. 2006 October 14 2006 October 15 Speedy Mic‘s rotation XMM orbit 1254 VLT visibility XMM observations The observations: Synchronizing orbits, night-time visibility, instrument schedules, …  50 ks XMM-Newton data + 142 VLT/UVES spectra

  3. The target: Speedy Mic (BO Mic)A single K-dwarf - ultrafast and highly active P = 0.380 ± 0.004 d ( Cutispoto et al. 1997 ) v sini = 132 ± 2 km/s ( Wolter et al. 2005 ) A giant flare (E > 1036 erg) Kürster 1994 DSS, d ≈ 0.0002“

  4. CaKEquivalent width EPIC-pn Hα A „moderate“ flare in X-rays and optical ≈ 4.5 hours Rotation Phase Wolter et al. 2008  Total flare energy in soft X-rays:~ 1034 erg

  5. Chromospheric emissionRotational Modulation Ca II Kλ3933 Ǻ Wolter & Schmitt 2005

  6. A 2006 flare C C 9.4 h B B Rotation Phase A 1.7 Å@ 4000 Å Wavelength „unsharp masked“ Wavelength Rotation Phase Evolution of CaIIK Line Profiles

  7. log T [K] 0.5 · log EM [cm-3] Flare heating and cooling  Loop half length 240,000 km ≈ 0.4 R* Wolter, Robrade et al. 2008; Reale et al.2004

  8. <<<<<<<<<<< A flare in a context Phase 4.2 Phase 3.9 Wolter et al. 2008 ESO PR 53-2007 Phase 4.6

  9. Summary • X-ray flare sites can be localized by simultaneous optical/UV Doppler imaging • Flare sites are not necessarily conspicuous otherwise „ … on returning within 60 seconds was mortified to find that it was already much … enfeebled.“ (R. Carringon 1859, MNRAS XX) Wolter, Robrade, Schmitt & Ness 2008, A&A 478, L12ESO Press Release 53/07 „Speedy Mic‘s Photograph“

  10. Appendix

  11. Outlook: Chromospheric heating events Rotation Phase He I 5875, Ca II 3933 and XMM-pn at 300 s resolution

  12. A „solar-like“ spectrum Hα6562.81 Ǻ Na D25889.97 Ǻ Na D15895.94 Ǻ Hβ4861.34 Ǻ Ca II K 3933.68 Ǻ Ca II H 3968.49 Ǻ (NOAO) Arcturus (α Boo, K1 III, Teff ≈ 5200 K )

  13. The Doppler imaging principle: Line profiles → spatial information e.g. Deutsch 1958, Vogt & Penrod 1983, Wolter 2004

  14. Speedy Mic vs. SunUltrafast rotation and high activity Sun SpeedyMic Valenti 2001, Sterzig & Schmitt 1997, Cardini et al. 2007, Balihunas et al. 1995

  15. Lost and found

  16. „Ultrafast rotators“

  17. „Ultrafast rotators“

  18. BO „Speedy“ Mic in 2002 (HD 197890)

  19. Aug 2 „6400 Å“

  20. Aug 7 „6400 Å“

  21. Photometry 2002 (SAAO)

  22. The Prominences …

  23. Evolution of Hα(Aug 2) line profiles

  24. Hα(Aug 2) CaII K (Aug 2)

  25. „A densely packed prominence system beyond co-rotation“ Hα(Aug 2) Hα(July 19) r ≈ 5 ± 1.5 R* r = 3.5 ± 0.6 R* Rk = 1.95 ± 0.07 R* Dunstone et al. 2006 (adapted)

  26. RXJ 1508.6±4423 („post T Tauri“) Hα emission AB Dor Hα absorption transients Stellar prominences Donati et al. 2000 Collier Cameron & Robinson 1989

  27. The Plage(s) …

  28. Localizing one stellar plage φ = 112° θ = 130° CaIIK(Aug 2)

  29. „Localizing one (?) stellar plage“ (Aug 7) CaIIK(Aug 2) φ = 72° θ = 99° φ = 112° θ = 130°

  30. The Flare …

  31. APOD April 2006 Hα „Astronomers love stars …“ (Zirrin 1988) „… and we have a fine one right near us.“ DOT

  32. Hα pre-flare Hα flare (21:06 UT) The 1993 March 6 solar flare Johns-Krull et al. 1997

  33. GOES „soft X-ray“ 20:23 „Unfortunately, the observer was eating lunch when the flare began.“

  34. Solar flare Hα profiles (near max.)

  35. „after peak“ Another solar flare (Hα – 0.5 Å) higher density „raining down“ Zirrin 1988 (BBSO)

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