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The magnetic personalities of stars revealed by MOST

The magnetic personalities of stars revealed by MOST. Jaymie Matthews. Univ. of British Columbia Vancouver Canada. Ap star impersonator B ≈ 5 00 G age ≈ 1 Gyr. The magnetic personalities of stars revealed by MOST. Jaymie Matthews. Univ. of British Columbia Vancouver

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The magnetic personalities of stars revealed by MOST

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  1. The magnetic personalities of stars revealed by MOST Jaymie Matthews Univ. of British Columbia Vancouver Canada Ap star impersonator B ≈ 500 G age ≈ 1 Gyr

  2. The magnetic personalities of stars revealed by MOST Jaymie Matthews Univ. of British Columbia Vancouver Canada CP2star impersonator B ≈ 500 G age ≈ 1 Gyr CP2 = (Crazy Person)2

  3. The magnetic personalities of stars revealed by MOST Jaymie Matthews Univ. of British Columbia Vancouver Canada Ap star impersonator B ≈ 300 G age ≈ 60 Myr

  4. The magnetic personalities of stars revealed by MOST Jaymie Matthews Univ. of British Columbia Vancouver Canada Ap star impersonator B ≈ 20kG age ≈ 10 Gyr

  5. Evolution of space telescopes HST

  6. Evolution of space telescopes MOST to scale HST

  7. “Suitcase” in space MOST HST

  8. 10 yearsin space! MOST launched from Plesetsk 30 June 2013 HST Happy Birthday!

  9. Evolution of space telescopes MOST HST

  10. Evolution of space telescopes MOST BRITE HST

  11. Evolution of space telescopes MOST BRITE Constellation Canada 2 nanosats Austria 2 nanosats Poland 2 nanosats HST

  12. Evolution of space telescopes MOST BRITE Constellation Canada 2 nanosats Austria 2 nanosats Poland 2 nanosats launch 25 Feb 2013

  13. Evolution of space telescopes MOST BRITE Constellation Constellation Canada 2 nanosats Austria 2 nanosats Poland 2 nanosats launch 25 Feb 2013

  14. Carbatteryinspace Constellation

  15. Evolution of space telescopes MOST BRITE Constellation HST

  16. Evolution of stars MOST BRITE Constellation HST “retired” A-type

  17. Evolution of stars MOST BRITE Constellation HST “retired” A-type K giant

  18. Evolution of stars MOST BRITE Constellation HST “retired” B-type

  19. Evolution of stars MOST BRITE Constellation HST rapid rotation + dense winds “retired” B-type

  20. Evolution of stars MOST BRITE Constellation HST “retired” B-type

  21. Photometryof stars from space MOST, CoRoTand Kepler giveultra-precision and are being joined by BRITE Constellationto extend coverage of stellar parameter space MOST CoRoT Kepler BRITE not to scale

  22. The magnetic personalities of stars revealed by MOST Jaymie Matthews Univ. of British Columbia Vancouver Canada Ap star impersonator B ≈ 500 G age ≈ 1 Gyr

  23. The nonmagnetic personality... of an A star revealed by MOST David Mkrtichian Jaymie Matthews National Astronomical Research Institute of Thailand Univ. of British Columbia Vancouver Canada

  24. WASP-33 A bright, rapidly rotating A5 star (HD 15082) with a transiting gas giant planet in a 1.22-day retrograde orbit – 5.5 stellar radii from the star’s photosphere Trailed spectrum of rotation profile from the HERMES spectrograph (MERCATOR, La Palma) covering the transit on 26 October 2010 The longest high-resolution spectral time series of this system Several pulsation modes are seen Planet's spectral silhouette seen travelling in retrograde direction

  25. WASP-33 A bright, rapidly rotating A5 star (HD 15082) with a transiting gas giant planet in a 1.22-day retrograde orbit – 5.5 stellar radii from the star’s photosphere Trailed spectrum of rotation profile from the HERMES spectrograph (MERCATOR, La Palma) covering the transit on 26 October 2010 The longest high-resolution spectral time series of this system Several pulsation modes are seen Planet's spectral silhouette seen travelling in retrograde direction

  26. WASP-33 A bright, rapidly rotating A5 star (HD 15082) with a transiting gas giant planet in a 1.22-day retrograde orbit – 5.5 stellar radii from the star’s photosphere Trailed spectrum of rotation profile from the HERMES spectrograph (MERCATOR, La Palma) covering the transit on 26 October 2010 The longest high-resolution spectral time series of this system Several pulsation modes are seen Planet's spectral silhouette seen travelling in retrograde direction

  27. MOST light curve V = 8.3 45615 observations over 24 days in October 2010

  28. Phased to the orbital period P = 1.22 day retrograde orbit f = 9.84 cycles per day a = 0.001 mag

  29. Pulsation frequencies hybrid?

  30. The magnetic personalities of stars revealed by MOST

  31. MOST and magnetic stars Target Type Main objective HR 1217 roAp asteroseismology γ Equ roAp asteroseismology 10 Aql roAp asteroseismology HD 9289roAp asteroseismology HD 99563 roAp asteroseismology HD 134214 roAp asteroseismology σ Ori E B2Vpe wind physics HR 5907 B2Vpe wind physics exoplanet systemsstar-planet magnetospheric interactions

  32. MOST and magnetic stars Target Type Main objective HR 1217 roAp asteroseismology γ Equ roAp asteroseismology 10 Aql roAp asteroseismology HD 9289roAp asteroseismology HD 99563 roAp asteroseismology HD 134214 roAp asteroseismology σ Ori E B2Vpe wind physics HR 5907 B2Vpe wind physics exoplanet systemsstar-planet magnetospheric interactions

  33. roAp stars rapidly oscillating Ap • discovered by Don Kurtz in 1978 • ~45 members of the class • periods: 6 ~ 21 minutes • amplitudes: few mmag and less • p-modes of low-degree,high-overtone • global magnetic fields: B ~ 1 - 35 kG but see SuperWASP poster by Holdsworth & Smalley

  34. roAp stars freq. vs. T models by Hideyuki Saio

  35. roAp stars excitation models by Hideyuki Saio shaded region is where κ mechanism in H ionisation zone can excite high- order p-modes Z =0.02 Bpolar= 0 He-depleted He I ionisation zone ℓ=1 modes boundary condition at log τ = −6 running wave for ω > ωc

  36. roAp stars excitation models by Hideyuki Saio shaded region is where κ mechanism in H ionisation zone can excite high- order p-modes The preliminary models suggest that a mechanism other than H ionisation is needed to excite most roAp pulsations

  37. roAp stars excitation echelle diagram of modes gamma Equulei ν1 – ν6 MOST photometry Michael Gruberbauer (Mk1 – 1 c/d); Mk2 radial velocity data David Mkrtichian

  38. roAp stars excitation echelle diagram of modes gamma Equulei ν1 – ν6 MOST photometry Michael Gruberbauer (Mk1 – 1 c/d); Mk2 radial velocity data David Mkrtichian Model frequencies agree with observation but none are excited

  39. MOST and magnetic stars Target Type Main objective HR 1217 roAp asteroseismology γ Equ roAp asteroseismology 10 Aql roAp asteroseismology HD 9289roAp asteroseismology HD 99563 roAp asteroseismology HD 134214 roAp asteroseismology σ Ori E B2Vpe wind physics HR 5907 B2Vpe wind physics exoplanet systemsstar-planet magnetospheric interactions

  40. rapidly oscillating Ap star periods near 6 min 0 < B field < 1.2 kG P = 12.45877(16) d p-modes in magnetic stars HR 1217= HD 24712 50 µmag residuals 1 2 3 4 5 6 7 7 discovered by Kurtz (1982) 2 4 3 5 6 1 window rot spectral window Ryabchikova et al. (2005) Rich p-mode spectrum • 6 dominant modes + 1 anomalous one 2000WET campaign Kurtz et al. 2002, MNRAS 330, L57 Kurtz, Cameron et al. 2005, MNRAS

  41. MOST photometry Nov-Dec 2004 666hr over 29 days duty cycle = 96% 30-sec integrations custom optical filter p-modes in magnetic stars HR 1217 12.5 d = Prot’n 3 gaps due to charged particle hits 2004MOST campaign Chris Cameron PhD thesis, 2010, UBC

  42. p-modes in magnetic stars HR 1217 34 frequencies

  43. 105 YREC models Yale Rotating Evolution Code Z ↑ X↑ M = 1.3 →1.8 Mʘ in steps of 0.05 Mʘ Z = 0.008 → 0.022 in steps of 0.002 X= 0.70, 0,72, 0.74 α = 1.4, 1.6, 1.8 569 models in error box used for pulsationmodeling values of large frequency spacing Δν

  44. p-modes in magnetic stars HR 1217 observed small spacing ~ 2.5 μHz small spacings of models • This value consistent with models of • low metallicity • Z < 0.01 • mass M ~ 1.5 Mʘ • age t > 1 Gyr

  45. Magnetoasteroseismology pulsation amplitudes & phases modulated with magnetic (= rotation) period Oblique Pulsator Model Kurtz 1982 MNRAS 200, 807

  46. Magnetoasteroseismology pulsation amplitudes & phases modulated with magnetic (= rotation) period Oblique Pulsator Model Kurtz 1982 MNRAS 200, 807 magneto-acoustic coupling Dziembowski & Goode 1996 eigenfunction expanded with Yℓm(θ,φ) Cunha & Gough 2002 Cunha 2006 variational principle and WKB approximation Saio & Gautschy 2004, Saio 2005 Bigot & Dziembowski 2002, A&A 391, 235 including rotation

  47. δP = 0 ∆ × B’ = 0 surface phase difference  vA > cs  0.95 R vA << cs magnetic slow wave acoustic wave Magnetoasteroseismology

  48. Re (  shift )  Magnetoasteroseismology Jumps in frequency  depend on model structure and on pulsation mode &magnetic field geometries Cunha 2006

  49. Magnetoasteroseismology Saio Expands magnetic contribution to hydrostatic equation in spherical harmonics Cunha Estimates magnetic contribution via a variational principle Qualitative agreement between both approaches

  50. Magnetoasteroseismology • Magnetic fields shift pulsation frequencies • The frequency shift changes depending on • the structure of the stellar envelope • Magnetic fields tend to damp pulsations • This effect seems strong enough to damp • low-overtone p-modes in roAp stars • Magnetic fields modify the latitudinal distribution • of pulsation amplitude • Amplitude confined to polar regions, as in HR 3831 • Theoretical models for Przybylski's Star, γEqu, • and 10 Aql agree with observed frequencies • but required Bp might be too big

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