Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques
VLTI/PIONIER imaging of red supergiant stars
Miguel Montargès (KU Leuven) FWO [PEGASUS]2 Marie Skłodowska-Curie fellow & Andrea Chiavassa (Lagrange), Benjamin Tessore (LUPM), Ryan Norris (GSU), Pierre Kervella (LESIA), and Agnès Lèbre (LUPM).
Imaging of Stellar Surfaces ESO Garching - 8th March 2018
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie Grant agreement No. 665501 with the research Foundation Flanders (FWO)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 1/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Stellar evolution
Asymptotic Giant Branch stars : progenitor . 8 M Red supergiant stars : progenitor & 8 M
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 2/20 → Study of the photosphere + CSE
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Trigerring the RSG mass loss
Physical process remains unknown (no flares, no large pulsations) Josselin & Plez (2007) suggested a convection triggered mass loss Auriere et al. (2010) observed magnetic field ∼ 1 G + Airapetian et al. (2000): model Alfvén-wave triggered outflow
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 3/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Trigerring the RSG mass loss
Physical process remains unknown (no flares, no large pulsations) Josselin & Plez (2007) suggested a convection triggered mass loss Auriere et al. (2010) observed magnetic field ∼ 1 G + Airapetian et al. (2000): model Alfvén-wave triggered outflow → Study of the photosphere + CSE
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 3/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Spatial scales
(P. Kervella)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 4/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Monitoring of Betelgeuse (α Ori)
VLTI/PIONIER observations (4 telescopes, H band, low spectral resolution, R = 40) 4 epochs of monitoring: Jan. 2012, Feb. 2013, Jan. 2014 and Nov. 2014 Only the compact array configuration (baseline length ∈ [11; 36 m]) ⇒ Montargès et al. (2016), A&A, 588, A130
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 5/20 AND litterature value ∼ 42 mas
Consistent between the 4 epochs (3 different features to avoid detector saturation)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: angular diameter (2013)
0 (N)
25 Limb-darkened disk fit: 20
15 44.21 vs 48.56 mas
10 ⇒ 10% difference !
5
90 270 (E) (W)
180 (S)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 6/20 Consistent between the 4 epochs (3 different features to avoid detector saturation)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: angular diameter (2013)
0 (N)
25 Limb-darkened disk fit: 20
15 44.21 vs 48.56 mas
10 ⇒ 10% difference !
5
90 270 (E) (W) AND litterature value ∼ 42 mas
180 (S)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 6/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: angular diameter (2013)
0 (N)
25 Limb-darkened disk fit: 20
15 44.21 vs 48.56 mas
10 ⇒ 10% difference !
5
90 270 (E) (W) AND litterature value ∼ 42 mas
Consistent between the 4 epochs (3 different features to avoid detector saturation)
180 (S)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 6/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: Shape of the closure phase (2013)
200
150
100
50
0
50 Closure phase (degree)
100
150
200 40 50 60 70 80 90 100 110 120 1 Maximum spatial frequency (arcsec− )
Strong signal Incompatible with elliptical model
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 7/20 LDD disk + bright spot : good agreement + angular diameter consistent with literature (∼ 43 mas) Consistent on the 4 epochs B Photocenter displacement up to 2 mas (π ∼ 6 mas)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: LDD model + gaussian bright spot
Chiavassa et al. (2009, 2010) showed that convection can bias angular diameter measurements
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 8/20 Consistent on the 4 epochs B Photocenter displacement up to 2 mas (π ∼ 6 mas)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: LDD model + gaussian bright spot
Chiavassa et al. (2009, 2010) showed that convection can bias angular diameter measurements LDD disk + bright spot : good agreement + angular diameter consistent with literature (∼ 43 mas)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 8/20 B Photocenter displacement up to 2 mas (π ∼ 6 mas)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: LDD model + gaussian bright spot
Chiavassa et al. (2009, 2010) showed that convection can bias angular diameter measurements LDD disk + bright spot : good agreement + angular diameter consistent with literature (∼ 43 mas) Consistent on the 4 epochs
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 8/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: LDD model + gaussian bright spot
Chiavassa et al. (2009, 2010) showed that convection can bias angular diameter measurements LDD disk + bright spot : good agreement + angular diameter consistent with literature (∼ 43 mas) Consistent on the 4 epochs B Photocenter displacement up to 2 mas (π ∼ 6 mas)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 8/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Antares observation (α Sco)
VLTI/PIONIER observations (4 telescopes, H band, low spectral resolution, R = 40) 3 different configurations (baseline lengths : 11-150 m) ⇒ Montargès et al. 2017, A&A, 605, A108
0 (N)
20.0 17.5 15.0 12.5 LDD diameters (at 1.61 µm): 10.0 7.5 5.0 37.70-39.03 mas 2.5 90 270 ⇒ 4% difference (E) (W)
AND does not fit the closure phases !
180 (S)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 9/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Antares: dataset
100 LDD Power Data 10-1
10-2
10-3
10-4
10-5
10-6 Squared visibility
10-7
10-8
10-9
10-10
10-11 0 50 100 150 200 250 300 350 400 450 1 Spatial frequency (arcsec− )
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 10/20 ⇒ Modeling using random distribution of spots with a fixed size !
Best match: Gaussian spot distributions with a FWHM of 17 and 2 mas (not resolved !) LDD diameter: 37.89 ± 0.10 mas at 1.61 µm χ2(V 2 + CP) as low as 28 (627 for best LDD alone)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Antares: modeling
B Weak signal compared to Betelgeuse → small spots ? B Angular resolution ∼ 1/16th of the stellar diameter !
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 11/20 Best match: Gaussian spot distributions with a FWHM of 17 and 2 mas (not resolved !) LDD diameter: 37.89 ± 0.10 mas at 1.61 µm χ2(V 2 + CP) as low as 28 (627 for best LDD alone)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Antares: modeling
B Weak signal compared to Betelgeuse → small spots ? B Angular resolution ∼ 1/16th of the stellar diameter ! ⇒ Modeling using random distribution of spots with a fixed size !
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 11/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Antares: modeling
B Weak signal compared to Betelgeuse → small spots ? B Angular resolution ∼ 1/16th of the stellar diameter ! ⇒ Modeling using random distribution of spots with a fixed size !
Best match: Gaussian spot distributions with a FWHM of 17 and 2 mas (not resolved !) LDD diameter: 37.89 ± 0.10 mas at 1.61 µm χ2(V 2 + CP) as low as 28 (627 for best LDD alone)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 11/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques CE Tau
Program VLTI/PIONIER DDT program (4 telescopes, H band, low spectral resolution, R = 40) 2 configurations (baseline lengths : 7-97 m)
Results Angular diameter from disk models cur ini Basic stellar parameters (R?,L?,Teff , age, M? ,M? , log g) → Better constraints for physical models ⇒ Montargès et al., A&A, in press.
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 12/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques CE Tau@PIONIER: images
November 2016 December 2016
8 1.0 8 1.0
6 6
0.8 0.8 4 4
2 2 0.6 0.6
0 0
0.4 0.4 2 2 Relative intensity Relative intensity Relative Dec. (mas) Relative Dec. (mas)
4 4 0.2 0.2
6 6
8 0.0 8 0.0 8 6 4 2 0 2 4 6 8 8 6 4 2 0 2 4 6 8 Relative R.A. (mas) Relative R.A. (mas)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 13/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques 3D RHD simulations
CO5BOLD (Freytag 2012) + Optim3D (Chiavassa 2009) codes → "Star in a box" Principle : comparing interferometric observables
(see S. Höfner & B. Freytag’s talks)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 14/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Comparisons
α Sco α Ori CE Tau Parameter (Antares) (Betelgeuse) Simulation st35gm03n13 st36g00n04 st35gm03n13 13 ± 2 21 ± 2 14.37+0.02 M (M ) −1.91 12 6 12 ∼ 680 897 ± 211 590 ± 85 R (R ) 846 ± 1.1 386.2 ± 0.4 846 ± 1.1 3660 ± 120 3690 ± 54 3810 ± 135 T (K) eff 3430 ± 8 3663 ± 14 3430 ± 8 7.59 ± 3.12 12.7 ± 6.0 6.61 ± 2.07 L (104 L ) 8.95 ± 0.086 2.42 ± 0.037 8.95 ± 0.086 −0.15 ± 0.05 −0.39 ± 0.22 0.05+0.11 log g −0.17 −0.354 ± 0.001 0.023 ± 0.001 −0.345 ± 0.001 Reduced χ2 253 390 98 All simulations are scaled to the star’s angular diameter Simulations: Chiavassa+ 2011 Antares: Ohnaka+ 2013; Betelgeuse: Ohnaka+ 2011 and Montargès+ 2014; CE Tau: Montargès+ 2018
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 15/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Simulations + images
November 2016 December 2016
8 1.0 8 1.0
6 6
0.8 0.8 Tremblay et al. 2013 4 4
2 2 contrast. 0.6 0.6
0 0
0.4 0.4 2 2 Relative intensity Relative intensity Relative Dec. (mas) Relative Dec. (mas)
4 4 0.2 0.2
Images: 6 6 δI / hIi = 5 − 6 ± 1% rms 8 0.0 8 0.0 8 6 4 2 0 2 4 6 8 8 6 4 2 0 2 4 6 8 Relative R.A. (mas) Relative R.A. (mas)
6 6
1.6 1.2 4 4 1.4 Original simulation: 1.0
δIrms/ hIi = 23 ± 1% 2 1.2 2 0.8 1.0 0 0 Convolved simulation: 0.8 0.6
2 0.6 Relative intensity 2 Relative intensity δIrms/ hIi = 16 ± 1% Relative Dec (mas) Relative Dec (mas) 0.4 0.4 4 4 0.2 0.2
6 0.0 6 0.0 6 4 2 0 2 4 6 6 4 2 0 2 4 6 Relative RA (mas) Relative RA (mas)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 16/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Ongoing project: spectral dispersion
12
11
10
9 Angular diameter (mas)
1.0 Br- CO 2-0 CO 3-1 CO 4-2 CO 5-3 CO 6-4 CO 7-5
0.8
0.6 Relative flux 0.4
0.2 2.0 2.1 2.2 2.3 2.4 Wavelength ( m)
VLTI/GRAVITY observations in October 2017
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 17/20 (Courtesy of A. Chiavassa)
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: comparison with visible spectro-polarimetry
Montargès et al. 2016 & Aurière et al. 2016 (see talks of A. López-Ariste + A. Lèbre)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 18/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: comparison with visible spectro-polarimetry
Montargès et al. 2016 & Aurière et al. 2016 (see talks of A. López-Ariste + A. Lèbre)
(Courtesy of A. Chiavassa)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 18/20 VLT/SPHERE (visible) Kervella et al. 2016
ALMA continuum ALMA lines O’Gorman et al. 2017 Kervella et al. 2018
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: comparison with visible + radio imaging
VLTI/PIONIER (NIR) Montargès et al. 2016
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 19/20 ALMA continuum ALMA lines O’Gorman et al. 2017 Kervella et al. 2018
Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: comparison with visible + radio imaging
VLTI/PIONIER (NIR) VLT/SPHERE (visible) Montargès et al. 2016 Kervella et al. 2016
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 19/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques Betelgeuse: comparison with visible + radio imaging
VLTI/PIONIER (NIR) VLT/SPHERE (visible) Montargès et al. 2016 Kervella et al. 2016
ALMA continuum ALMA lines O’Gorman et al. 2017 Kervella et al. 2018
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 19/20 Mass loss of evolved stars Analysis through models Image reconstructions Numerical simulations Other techniques A possible origin of the mass loss ?
(VISIR, mid-IR, Kervella et al. 2011)
Miguel Montargès VLTI/PIONIER imaging of red supergiant stars 20/20