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SIAMOIS Sismomètre Interférentiel A Mesurer les Oscillations des Intérieurs Stellaires
Asteroseismology in Antarctica at Dome C
Benoît Mosser, Michel Auvergne, Thierry Appourchaux, Annie Baglin, Caroline Barban, Claude Catala, Marc-Antoine Dupret, MarieJo Goupil, Jean-Pierre Maillard, Eric Michel, Reza
Samadi, Francois-Xavier Schmider, Frédéric Thévenin, Gérard Vauclair et al.
Observatoire de Paris (LESIA, GEPI), IAP, IAS, UNSA/LUAN, OMP/LATT, OCA
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In 2009
has achieved a huge program
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AND THEN ?
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Scientific goals
Step 1: photometry in space
For complementary observations: photometry in space / ground based spectrometric observations• Low mass stars• Doppler information (limited granulation noise, l = 3 modes)• Long term variations• Follow up of targets revealed by COROT• Questions raised by COROT…
In the best site for long-duration continuous observations :
at Dome C in Antarctica
• Solar like oscillations• Stellar interior
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Step 2 … ground-based spectrometry
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Dome C
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Duty cycle > 90 %
during 3 months
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Properties at Dome C
• Wintering: full night = 3 months
• Duty cycle: > 90 % (Agabi, 2005)
• Much better performances compared to a network(duty cycle limited to 65%; heavy coordination)
• Conditions similar to space
Properties of Dome C are already OK for asteroseismology~ Space project
Asteroseismology at Dome C:
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Strategy for Dome C
2009/2010 Integrated project :+ small telescope+ dedicated Fourier Transform seismometer
2010+ Spectrometer + spectropolarimeter2-m class telescope
• INSU (Astronomy) / Antarctic group:- promotes observations at Dome C- has to identify small size projects to be realized as a first step
• PNPS (Stellar physics): - promotes the rapid development of a dedicated asteroseismometer to be installed at Dome C
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• Fourier Transform seismometry: the Doppler signal is deduced from a limited portion of the interferogram of the stellar visible spectrum
• FT seismometry successfully tested with the FTS at CFHT Procyon (Mosser et al. 1998, A&A 340, 457)
• Principle of an instrument dedicated to asteroseismology Photon noise limited performances:
Q = quality factor ; Ne = photoelectrons
+ low resolution dispersion (Mosser et al. 2003, PASP 115, 990)
Fourier transform seismometry
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Performances
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Photon noise limited performances SIAMOIS at Dome C, 40-cm telescope, 120 hrs, mV = 4, duty cycle = 95% ‘‘SNR’’ of circumpolar targets
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Asteroseismic targets
Observable targets with SIAMOIS and a 40-cm
telescope
• 40-cm tel : - 8 targets F, G and K, IV & V, with solar like oscillations- more than 30 red giants
- many Scuti with v sin i < 20 km/s• Program for more than 3 winterovers
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Project and instrument
• 40-cm telescope low cost, easy ‘antartization’, dedicated to the projet • Interferometer monolithic instrument
no moving part, reduced sizefiber fed
• Post-dispersion efficiency, photon noise limited performances
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Schedule
• 2004: faisability - Realisation and test of the only critical subsystem
• 2005: phase A (funded)- Design of the instrument for Antarctic- Integrated project with a small collector- Positive recommendation from the WG of PNPS (stellar physics)
• 2006: end of phase A + phase B- Design of the full instrument ; thermo-mechanical analysis- Prototype, tests….
• 2008- Transfer at Dome C
• 2009: winterover at Dome C
InterferometerJP Amans GEPI
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‘‘Big science’’ at Dome C for < 1 ME