June 15, 2006 ARENA workshop 1

SIAMOIS Sismomètre Interférentiel A Mesurer les Oscillations des Intérieurs Stellaires

Seismic Interferometer to Measure Oscillations in the Interior of Stars

Benoît Mosser, Tristan Buey, Claude Catala, Michel Auvergne, Thierry Appourchaux, Annie Baglin, Caroline Barban, Marc-Antoine Dupret, MarieJo Goupil, Jean-Pierre Maillard, Eric Michel, Reza Samadi,

Francois-Xavier Schmider, Frédéric Thévenin, Gérard Vauclair, Denis Fappani et al. Observatoire de Paris/LESIA, IAS, UNSA/LUAN, OMP/LATT, IAP, OCA

June 15, 2006 ARENA workshop 2

Asteroseismology

The Sun without asteroseismic constraints !

What asteroseismology teaches us ? …. Example of the Sun

June 15, 2006 ARENA workshop 3

Asteroseismology

The Sun without asteroseismic constraints !

What asteroseismology teaches us ? …. Example of the Sun

June 15, 2006 ARENA workshop 4

Asteroseismology after COROT

1st step: photometry, space-based observations2nd step : spectrometry, ground-based obs.

Complementary observations • Bright stars• Low mass stars• Doppler signalreduced granulation noise, modes l=3

Scientific specifications: continuous observations, long duration

June 15, 2006 ARENA workshop 5

SIAMOIS at Dome C

Demanding site ? Project ~ spatial organization

Quasi automatic, simple setup

Reduced mass, power, telemetry

Seeing ? Fibre = 5" on the sky

No big telescope available at Dome C ?

Key science with a 40-cm telescope

Only circumpolar targets ? Enough interesting bright targets for more than 6 winterings

Duty cycle ~ 90% ! Scientific specification #1 : duty cycle > 85%

Polar night = 3 months Scientific specification #2 : 100-day long run on the same target

June 15, 2006 ARENA workshop 6

Scientific program

Observable targets with SIAMOIS and a

40-cm telescope dedicated to the

project

• 40-cm telescope:- 7 targets, type: F, G, K class: IV & V

- many red giants; Scuti (v sin i < 20 km/s)

Scientific programme for more than 6 winterings

COROT

June 15, 2006 ARENA workshop 7

Overall description

• Divided in four sub-systems :

– A dedicated Telescope with its Bonnette (telescope guiding and fiber coupling).

– An Interferometer and a Camera.

– A structure for thermal and mechanical control.

– A command/control software system.

• Divided in five laboratories :

– GIGT from OMP (Observatoire Midi-Pyrennée).

– LUAN from OCA (Observatoire Côte d’Azur).

– IAS (Institut d’Astrophysique Spatiale).

– LESIA from OPM (Observatoire Paris-Meudon).

– CSIC from Institutode Astrofisica de Andalusia (in discussion).

• One associated private contractor :

– SESO (Société Européenne de Systèmes Optiques).

June 15, 2006 ARENA workshop 8

Instrument

Thermo-mechanical structure.

Optical bench.

Interferometer

Camera

Dedicated Telescope

Bonnette

Calibration

Optical fibers : signal and calibration

Command/control system: Acquisition,image processing …

Vacuum pump

June 15, 2006 ARENA workshop 9

Instrument

• 40-cm telescope low cost, easy ‘antarctization’, dedicated to the projet • Interferometer monolithic instrument

no moving part, reduced sizefiber fed

• Post-dispersion efficiency, photon noise limited performances

June 15, 2006 ARENA workshop 10

The constraints.

• Small budget and short planning…

• High reability of the instrument :

– Observation requirements : 90% of duty cycle.

– Very difficult to fix anything at Dome C in Antarctica.

• Very easy to use :

– Not easy set-up at Dome C in Antarctica (once again :-) ).

– Wintering will insure a minimal maintenance.

• Rather hard environmental conditions :

– Shocks and temperature (level and gradient) during transportation and storage.

– Temperature, humidity and pressure during operation.

June 15, 2006 ARENA workshop 11

Planning

• 2004- design- Achievement of the feasibility phase.

• 2006- thermo-mechanical analysis - Qualification tests.

• 2007- PDR- FDR

• 2008- integration

• 2009- tests- summer campaign: Dome C

• 2010

- first winterover at Dome C

Laboratories: LESIA (Obs. Paris), IAS (Orsay), LUAN (Nice), LATT (Toulouse) + SESO

SIAMOIS InterferometerJP Amans, GEPI, Obs Paris

Coast : 860 k€Including ANR : 460 k€

For phase A in 2006(ACI + CSA + PNPS) : 116 k€

June 15, 2006 ARENA workshop 12

Development Philosophy

• Step I : Establish all the requirements of the sub-systems and the interfaces between them.

• Step II : Develop the test benches and equipments, write the invitation to tender for the industrial contractors.

• Step III : Develop the sub-systems (industries and laboratories) or buy them directly when possible (budget and specifications).

• Step IV : Individual acceptance of each sub-systems.• Step V : Environmental qualification.• Step VI : Integration of the sub-systems together up to the instrument level.• Step VII : End-to-end test in laboratory and on the sky, final setup.• Step VIII : After transportation to Dome-C, simple integrity test.

• Some revue are foreseen during the project development.• Like “space instrument” development : quality, management of

configuration, documentation, revues… with limitations!

June 15, 2006 ARENA workshop 13

• Dome C: a unique site for asterosismology3-month continuous observation with duty cycle ~ 90%

• A specific scientific program after• High performances with a 40-cm collector

– Pioneering project at Dome C– FT seismometry: suitable concept for installation and setup at Dome C– Multiplex advantage of FT spectrometry– Small instrument : < 300kg, < 2m3, < 1kW, …– Rather fast development with a demonstrate feasibility.

Conclusion

‘‘Big science’’  at Dome C with a budget < 1 M€