1. Strategy of radial velocity follow-up
F. Bouchy1,2, Geneva and Marseille exo teams
1 Observatoire de Genève
2 Laboratoire d’Astrophysique de Marseille
COROT Week 3 – Dec. 2002

2. Characterize the mass of exo-planets
detected by COROT

3. HARPS 80 more efficient than CORALIE !
Fiber-fed cross-dispersed Echelle spectrograph
Wavelength coverage: 380nm < l < 690nm
Simultaneous reference (ThAr)
Spectral resolution: R=100’000
Vacuum operation, T-control
80 more efficient than CORALIE !

4. Tungsten lamp fiber A
26 red orders
44 blue orders

5. Sun fiber A

6. Thorium fibers A and B
Photon noise = 10 cms-1

7. Tracking capability
19 cm/s RMS

8. Expected photon noise
1 m/s
K G F
T_exp(s) = ^ mv (S/N = 500) 13

10. Probability to find a planet
N stars having a planet
N stars of the sample
around F, G, K dwarf :
1 – 10 %
(function of the metallicity)

11. Mass function
~ 1/M

12. Estimation of transit detections
30’000 F,G,K dwarfs with P < 50 days
2 < P < 10 days
Ptransit ~ 7.7%
Pexo-planets ~ 15%
10 < P < 50 days
Ptransit ~ 2.6%
Pexo-planets ~ 15%
1 – 10 MJ [1-10 transits]
0.1 – 1 MJ [ transits]
3 – 30 Mearth [25 transits]
1 – 10 MJ [1-3 transits]
0.1 – 1 MJ [3-30 transits]
3 – 30 Mearth [8 transits]

13. Estimation of transit detections
1 – 10 MJ
[~ 10 transits]
K > 100 m/s
0.1 – 1 MJ
[~ 100 transits]
K > 10 m/s
3 – 30 Mearth
[~ 30 transits]
K > 1 m/s

14. 5 Mearth 10 Mearth 15 Mearth F0 (1.60 Ms) 158 40 18 G0 (1.05 Ms) 10426 14
K0 (0.79 Ms) 78 20 9
M0 (0.51 Ms) 50 13 6
Nb of Doppler measurements (1 m/s) need to constrain
the mass (10% level) of transit detected planets orbiting at 0.1 AU
(HARPS 1 hour for mv = 13 / 2.5 hours for mv = 14)

15. HARPS 3.6m ESO
3 – 30 Mearth
[~ 30 transits] 30 x 26 x 2.5 hours ~ 240 nights
(10 Mearth AU - G0 - mv=14)
50 nights already allocated
Possibility to follow-up immediately a detected transit
Complet with ESO proposal (75 nights by year)

16. UVES+FLAMES 8.2m VLT (7 x HARPS)
0.1 – 1 MJ
[~ 100 transits] 100 x 26 x 0.16 / 7 hours ~ 8 nights
(0.3 MJ AU - G0 - mv=16)
ESO proposal  ~ 12 months of delay

17. SOPHIE 1.93m OHP (1/8 x HARPS) 0.1 – 1 MJ
[~ 25 transits] 25 x 26 x 0.2 hours ~ 16 nights
(0.3 MJ AU - G0 - mv=14)
[~ 100 transits] 100 x 26 x 1.2 hours ~ 390 nights
(0.3 MJ AU - G0 - mv=16)

18. CORALIE 1.2m La Silla (1/80 x HARPS)
1 – 10 MJ
[~ 10 transits] 10 x 26 x 1 hours ~ 32 nights
(3 MJ AU - G0 - mv=16)
All objects > 10 MJ
100 nights already allocated
Possibility to follow-up immediately a detected transit

20. Ground-Based Doppler Preparatory Observations for an exo-planet field
F. Bouchy1,2, Geneva and Marseille exo teams
1 Observatoire de Genève
2 Laboratoire d’Astrophysique de Marseille
COROT Week 3 – Dec. 2002

21. GIRAFFE spectrograph FOV 25 arcmin Multi-objects facilities
up to 130 objects
R ~ 20’000
Dl ~ 25 nm
360 – 940 nm

22. Goal 1 : Observe all bright stars of an exo-field
A 25 arcmin field contains ~ 100 stars up to mv = 13.5
1 exo-field ~ 25 Giraffe fields
1 hour on mv = => S/N = 80
Spectroscopic characterization (metallicity, …)
Check the spectral classification
provided by WF BVRI photometry
Activity (characteristic emission lines)
2500 stars – 25 hours on VLT

23. Goal 2 : Detect hot Jupiters around bright stars of an exo-field
A 25 arcmin field contains ~ 100 stars up to mv = 13.5
30 min on mv = => S/N = 56 => dVrms = 35 m/s
Find up to 20 new hot Jupiters
Find binaries
Characterize stellar activities ???
Select high precision masks for the exo-field
6 x 25 x 0.5 hours = 9 nights on VLT