Origin of Photospheric Perturbations in Hot Massive Stars

Talk for the Montreal's DAC's Fest

Transcript

1. Matteo Cantiello KITP Fellow Kavli Institute for Theoretical Physics, UCSB Origin of Photospheric Perturbations in Hot Massive Stars
2. Stellar Structure Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
3. Physics in the FeCZ (e.g. Lighthill ‘52, Stein ‘67, Edmunds ’78, Goldreich & Kumar ’90, de Jager et al. ’91) Cantiello et al. 2009 Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
4. Effects from turbulent convection FeCZ Running waves Magnetic fields Turbulence Magnetic spots Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Standing waves Stochastically excited pulsation Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
5. Stellar Magnetic Fields Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
6. B-fields in massive stars (direct evidence) §About 30+ magnetic OB stars found (e.g. Donati, Hubrig, Neiner, Petit) §Detection through Zeeman spectral signature §Mostly dipolar, amplitude between 300 G and several kG §Bias toward strong, large scale fields §Origin unclear. Likely Fossil (Wade et al. 2010) §Similar to Ap/Bp stars ~ 5-15% ? Tau Sco Credits: Jardine & Donati Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
7. §OB stars show puzzling surface phenomena (e.g. DACs, LPV, Wind Clumping, Solar- Like Oscillations, Photometric variability, X- ray emission...) §Some of these phenomena are ubiquitous. Therefore can not be explained by large scale fields! (e.g. Schnerr+08) §Small scale / small amplitude fields? (e.g. Cranmer & Owocki 96, Fullerton+96, Kaper+97, Henrichs+05,13) (DACs: Kaper, Henrichs et al. 1999) B-fields in massive stars (indirect evidence) Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
8. Origin of B-fields in massive stars Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 § Fossil Fields § B-field is produced/retained during star formation § Field arranged into a stable configuration (Braithwaite & Nordlund 2006, Duez et al. 2010) §Contemporary Dynamo Action § Configuration of the flow that transforms kinetic energy into magnetic energy. B-field maintained against Ohmic dissipation. Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 (Cantiello et al. 2010, Augustson et al. 2010) Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
9. Dynamo Action in OB stars e.g. Main Sequence 20 M Sun §Dynamo in Convective Core (e.g. MacGregor & Cassinelli 2003, Augustson 2010) §Dynamo in Radiative Zone (e.g. Spruit 2002, implemented in stellar evolution codes) §Dynamo in Iron Convection Zone (Cantiello et al. 2009,2010; Cantiello & Braithwaite 2011) Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
10. Dynamo Action in OB stars e.g. Main Sequence 20 M Sun §Dynamo in Convective Core (e.g. MacGregor & Cassinelli 2003, Augustson 2010) §Dynamo in Radiative Zone (e.g. Spruit 2002, implemented in stellar evolution codes) §Dynamo in Iron Convection Zone (Cantiello et al. 2009,2010; Cantiello & Braithwaite 2011) Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 B-Fields probably not observable, but potentially important for evolution and final stages Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
11. Dynamo Action in FeCZ Subsurface convection Rotation + Shear (Cantiello, Braithwaite, Brandenburg et al. 2010) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 (Käpylä et al. 2008,2010; Hughes & Proctor 2008) Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
12. Equipartition B Field in FeCZ 4.8 4.6 4.4 4.2 4.0 logT eff 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Log L 0 0 500 500 500 1000 1000 1000 1500 1500 2000 B (G) 0 500 1000 1500 2000 2500 GAL 4.8 4.6 4.4 4.2 4.0 3.0 3.5 4.0 4.5 5.0 5.5 6.0 Log L 120 MSun 35 MSun 20 MSun 10 MSun 7 MSun Cantiello & Braithwaite ’11 Here we assume dynamo action! Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
13. Surface appearance Possible mechanisms 1) Magnetic Diffusion ~ 107 yr 2) Wind Advection ~ 1 yr 3) Magnetic Buoyancy ~ hours • The amplitude of a self contained magnetic feature scales as • If the field is still anchored to the convection zone plasma can flow through the tube and higher fields can be reached (up to equipartition with thermal pressure) (Cantiello & Braithwaite ’11) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
14. Surface B Field from FeCZ 4.8 4.6 4.4 4.2 4.0 logT eff 3 4 5 6 Log L 5 5 10 10 20 20 40 40 80 160 320 B (G) 0 5 10 20 40 80 160 > 320 GAL 4.8 4.6 4.4 4.2 4.0 3 4 5 6 Log L 35 MSun 20 MSun 10 MSun 7 MSun 120 MSun Cantiello & Braithwaite ’11 Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
15. Relevant timescales §TCross §TConvection §TBuoyancy §TRotation §TWind ~ hour 0.2 - 1 day ~ day 1 - 10 days 0.25 - 50 years Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
16. X-ray emission • OB stars emit X rays. These stars follow the relation Lx/Lbol ~ 10-7 (e.g. Pallavicini+81) • The Lx/Lbol relation only applies for stars earlier than B0-B1. It breaks down at lower L (e.g.: Cohen+97) 4.8 4.6 4.4 4.2 4.0 logT eff 3 4 5 6 Log L 5 5 10 10 20 20 40 40 80 160 320 B (G) 0 5 10 20 40 80 160 > 320 GAL 4.8 4.6 4.4 4.2 4.0 3 4 5 6 Log L Log(Lx/Lbol) > -7 -7 > Log(Lx/Lbol) > -8 Log(Lx/Lbol) < -8 35 MSun 20 MSun 10 MSun 7 MSun 120 MSun Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
17. For fields of ~ 100 G emerging at the surface this leads to a temperature increase of ~ 300 K. A hot, bright spot How they would look like? Cantiello & Braithwaite (2011) A very simple model: 1) Assume hydrostatic equilibrium 2) Assume thermal equilibrium 3) Assume beta >> 1 e.g. Parker (1955) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
18. For fields of ~ 100 G emerging at the surface this leads to a temperature increase of ~ 300 K. A hot, bright spot How they would look like? Cantiello & Braithwaite (2011) A very simple model: 1) Assume hydrostatic equilibrium 2) Assume thermal equilibrium 3) Assume beta >> 1 e.g. Parker (1955) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 Depth ~ 0.002 - 0.02 RSun (R*~10/20RSun )
19. How they would look like? Cantiello & Braithwaite (2011) A very simple model: 1) Assume hydrostatic equilibrium 2) Assume thermal equilibrium 3) Assume beta >> 1 e.g. Parker (1955) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 Depth ~ 0.002 - 0.02 RSun (R*~10/20RSun )
20. Spot in a convective star Spot in a radiative star (?) Bright Spots in Hot Massive Stars Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
21. Multiple transient co-rotating loops? Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 Henrichs & Sudnik (2013) Co-variability of UV and optical
22. High precision photometry CoRoT: HD 46149 (Degroote et al. 2010) CNES / David Ducros Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
23. Spots in a O8V star? Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 HD 46149 (Degroote et al. 2010) Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
24. HD51756 (Papics et al. 2011) Spots in a B0.5IV star? Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
25. “Red Noise” in O stars Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 (Blomme et al. 2011) Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
26. Surface Turbulence Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
27. Surface Turbulence Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 § Can be measured using spectroscopy. Microturbulence and Macroturbulence measure motions with coherence length smaller and larger than the line forming region respectively. §Tight correlation between FeCZ properties and microturbulence (Cantiello+09, Fraser+10, Firnstein+in prep.) Observed line profile Intrinsic line profile Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
28. Microturbulence and FeCZ Theoretical models € E g E t ≈ M c ρc ρs v c ξ ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ 2 Matteo Cantiello The Turbulent Surface of Massive Stars KITP – 05/23/2011 Cantiello et al. 2009 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
29. Microturbulence and FeCZ Theoretical models + VLT-Flames observations € E g E t ≈ M c ρc ρs v c ξ ⎛ ⎝ ⎜ ⎞ ⎠ ⎟ 2 Matteo Cantiello The Turbulent Surface of Massive Stars KITP – 05/23/2011 Cantiello et al. 2009 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
30. Macroturbulence in magnetic OB stars Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 C IV line Sundqvist al. (2013) non-magnetic ~ 2.5 kG ~ 20 kG Dipole Dipole P=538 d Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
31. Macroturbulence in magnetic OB stars Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 C IV line Sundqvist al. (2013) non-magnetic ~ 2.5 kG ~ 20 kG Dipole Dipole All broadening from macroturbulence P=538 d Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
32. Macroturbulence in magnetic OB stars Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 C IV line Sundqvist al. (2013) non-magnetic ~ 2.5 kG ~ 20 kG Dipole Dipole All broadening from macroturbulence All broadening from Zeeman Splitting P=538 d Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
33. 0 10 20 30 40 50 60 70 vmac [km/s] 0 5.0•104 1.0•105 1.5•105 2.0•105 0 [ ] 0 10 20 30 40 50 60 70 vmac [km/s] 0 5.0•104 1.0•105 1.5•105 2.0•105 0 [ ] NGC 1624ï2 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 T (K) Sundqvist al. (2013) ~TSurface ~ FeCZ x PMagnetic = PGas Macroturbulence in magnetic OB stars Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 x
34. 0 10 20 30 40 50 60 70 vmac [km/s] 0 5.0•104 1.0•105 1.5•105 2.0•105 0 [ ] 0 10 20 30 40 50 60 70 vmac [km/s] 0 5.0•104 1.0•105 1.5•105 2.0•105 0 [ ] NGC 1624ï2 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 T (K) Sundqvist al. (2013) ~TSurface ~ FeCZ x PMagnetic = PGas Macroturbulence in magnetic OB stars Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 x
35. Solar-like oscillations Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
36. Solar-like oscillations in massive stars Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 Belkacem et al. 2009 Corot detection of solar-like oscillations in the massive star V1449 Aql (B type Star) [However, see Aerts et al. 2011] Belkacem et al. 2010 Theoretical calculations of stochastically excited modes from sub-surface convection. Degroote et al. 2010 Corot detection of solar-like oscillations in an O-type star Cantiello et al. 2009 Suggest that near-surface convection in hot, massive stars could cause stochastically excited pulsations Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
37. Solar-like oscillations in O star Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 HD 46149 (Degroote et al. 2010) Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
38. “Red Noise” in O stars (Blomme et al. 2011) Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 §Variability in the CoRoT photometry of 3 hot O-type stars § No clear pulsations detected § Variability of stochastic nature § Near-surface convection, granulation or wind inhomogeneities Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
39. Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 HD46149 (Degroote+ 2010) HD51756 (Papics+ 2011) HD46150 HD46223 (Blomme+ 2011) HD46966 Photometric variability: HRD location Red Noise Spots/Solar-like Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
40. Matteo Cantiello Near-Surface Convection in Massive Stars KITP – October 24th 2011 HD46149 (Degroote+ 2010) HD51756 (Papics+ 2011) HD46150 HD46223 (Blomme+ 2011) HD46966 Photometric variability: HRD location Red Noise Spots/Solar-like Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
41. Testing the theory Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014
42. Detectability of Small Scale Fields Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 Filling Factor: 0.5 Spot Angular Radius: 10º Spot Angular Radius: 2º (Kochukhov & Sudnik 2013)
43. Detectability of NRP Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 Aerts et al. 2010
44. BA Supergiants Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 (Shultz et al. 2013)
45. WR Stars Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 (Michaux et al. 2013) (vanGenderen et al. 2013) (Grassitelli et al. In prep) (St.-Louis et al. 2009) (Chene’ et al. 2011)
46. To summarize what we know Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 § Iron Convection zone seems to exist and be responsible for surface turbulence § E.g. Cantiello et al. 2009, Sundqvist et al. 2013, Solar-Like oscillations § Ubiquitous large scale B-fields ruled out § E.g. Schnerr et al. 2008, David-Uraz+ 2013, Shultz et al. 2013, MIMES § Small-Scale fields still possible, but if they exist they’re hiding pretty well § E.g. Cantiello & Braithwaite 2011, Kochukhov & Sudnik 2013, Henrichs & Sudnik 2013 §WR stars: show photometric variability and DACs § Possibly the same physics: Grassitelli et al. In Prep., Chene’ et al 2011, St- Louis et al. 2009, vanGenderen et al. 2013, Michaux et al. 2013
47. To summarize what we know Matteo Cantiello Magnetic Fields & Massive Stars Evolution Santa Barbara – 06/17/2011 Matteo Cantiello Pulsations and Magnetic Fields in Massive Stars IAU GA SpS13 – Beijing 2012 Matteo Cantiello Pulsations, Turbulence and Magnetic Fields in Massive Stars NORDITA – Stockholm 2013 Matteo Cantiello Origin of photospheric perturbations in hot massive stars Montreal 2014 § Puzzling variability, solar-like oscillations / red-noise in high-precision photometric data § E.g. de Groote et al. 2010, Papics et al. 2011, Blomme et al. 2011 § NRP might also play a role (but requires some ubiquitous superposition of modes to explain observations) § E.g. de Jong et al. 1999