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GONG 2010 - SoHO 24
A new era of seismology of the Sun
and solar-like stars
Aix-en-Provence, France
Sarbani Basu
Yale Unoversity
GONG 2004 – SoHO 14
Helio- and Asteroseismology: Towards a
Golden Future
New Haven, CT, USA
The future is here!
GONG: Alive and well
And after years of waiting in anticipation
We can actually do serious
asteroseismology now!
In fact, we find
ourselves
drowning in data.
“At first sight it would seem that the deep interior of
the Sun and stars is less accessible to scientific
investigation than any other region of the universe. Our
telescopes may probe farther and farther into the
depths of space; but how can we ever obtain certain
knowledge of that which is being hidden behind
substantial barriers? What appliance can pierce through
the outer layers of a star and test the conditions
within?”
Sir Arthur Eddington in “The
internal constitution of stars”
(1926)
The questions have changed.
Early concerns for helioseismology were the structure
and dynamics of the Sun (the questions that we face in
asteroseismology today).
Current issues deal with more detailed (and more
difficult!) phenomena.
Local Helioseismology
3D Inversions
Target Depth 1 Mm
6/28/2010
Target Depth 5 Mm
GONG 2010 Aix-en-Provence
How deep are Sunspots?
Acoustic haloes: Surface effect?
And what of the discrepancies?
Wave-speed below sunspots
1) Results are inconsistent for depths > 2 Mm
2) For all methods and models, except TD: increased
wave-speed for depths < 2 Mm.
J. Zhao & HMI team
A. Birch & D. Braun
phase-speed filters
ridge filters
yield near-surface inflows
yield near-surface outflows
The question of solar activity and activity
related changes
Solar oblateness changes, radius does not. Will PICARD confirm this?
Is there a 2nd solar dynamo?
Do we really know the microphysics of
stars?
Could we please, please get our acts together and solve the solar
abundance problem?
When will the opacity measurement results be available?
Please sir, could I have some more (equation of state calculations)?
Hey, we can do asteroseismology now!
Problems: Mode identification!
Stellar activity in mode parameters? The case of
HD49933
G modes?
GOL
F
5.81
σ
Mod
el
Adding 5 g modes l=1
(n=-4, -6, -8, -9 , -10)
On the evolution of the rotation of the young Sun (compared to Bouvier observations)
and its present profile obtained for different initial rotation rates A: no braking light
blue on left figure, B and C with braking (B: 20km/s on ZAMs navy blue on left figure,
C: 50 km/s) and a transport of momentum including diffuive and advective terms, see
poster Model-15
Turck-Chièze et al. ApJ 1st June 2010, 715, 1539
And what is HMI up to?
HMI Optics Package (HOP)
Connector Panel
Z
Focal Plane B/S
Shutters
X
Alignment Mech
Limb Sensor
Y
Fold Mirror
Oven Structure
Detector
(Vector)
Michelson Interf.
Lyot Filter
CEBs
Detector
(Doppler)
Vents
Limb B/S
Front Window
Active Mirror
Polarization Selector
Front Door
Telescope
Focus/Calibration Wheels
Mechanical Characteristics:
OP Structure
Box: 0.84 x 0.55 x 0.16 m
Over All: 1.19 x 0.83 x 0.29 m
Support Legs (6)
Mass: 39.25 kg
First Mode: 63 Hz
HMI Data Products and Objectives
HMI Data
Processing
Data Product
Science Objective
Global
Helioseismology
Processing
Internal rotation Ω(r,Θ)
(0<r<R)
Tachocline
Internal sound speed,
cs(r,Θ) (0<r<R)
Differential Rotation
Local
Helioseismology
Processing
Full-disk velocity, v(r,Θ,Φ),
And sound speed, cs(r,Θ,Φ),
Maps (0-30Mm)
Activity Complexes
Filtergrams
Carrington synoptic v and cs
maps (0-30Mm)
Observables
Doppler
Velocity
High-resolution v and cs
maps (0-30Mm)
Deep-focus v and cs
maps (0-200Mm)
Far-side activity index
Line-of-sight
Magnetograms
Vector
Magnetograms
Continuum
Brightness
Line-of-Sight
Magnetic Field Maps
Meridional Circulation
Near-Surface Shear Layer
Active Regions
Sunspots
Irradiance Variations
Magnetic Shear
Flare Magnetic Configuration
Flux Emergence
Magnetic Carpet
Coronal energetics
Vector Magnetic
Field Maps
Large-scale Coronal Fields
Coronal magnetic
Field Extrapolations
Far-side Activity Evolution
Coronal and
Solar wind models
Brightness Images
Solar Wind
Predicting A-R Emergence
IMF Bs Events
Version 1.0w
a) Spectrum of 8 hours of HMI Doppler data near disk center; b)
Spectrum of 8 hours of MDI hi-res data (from 1996);
Magnetic Field Blos Mean Field
HMI – MDI – WSO
Early HMI Magnetic Field
Frame of Vector Field Movie from Mar 29 Sunspot
K. Hayashi, R. Centeno Eliot, et al.
Early HMI Magnetic Field Observations
Meridional flows from Fourier-Legendre
decomposition
Spectral Comparison: HMI V vs AIA 1700
(period 2)
Dynamos and flows
And in the case of massive stars, primordial fields will probably play a large
role.
Can we detect large scale flows?
And what can we look forward to?
• SONG: Definitely
• PLATO: We really hope so!
• Stellar Imager:
• Solar Orbiter:
Issues
• Theory is lagging behind: how do we deal will
waves in a dispersive magnetic medium?
• Will we be able to detect deeper flows in the
Sun? And do the flows look anything like the
simulations show?
• What is the best way to analyze (and model)
current data?
We shall meet again in
Cairns, Australia, Nov 12-16, 2012