1 A. Boccaletti Pasadena, Sept th Imaging EGPs with JWST/MIRI and VLT/SPHERE valuable experiences for TPF-C A. Boccaletti, P. Baudoz D. Rouan + coronagraphic Paris Observatory

2 A. Boccaletti Pasadena, Sept th MIRI coronagraph concept monochromatic coronagraphs 4 masks in focal plane BB temperature undersampled NH3 abundance MIRI is not optimized for Coronagraphy (because of JWST …) we are looking at contrast ratio … but still of interest in the current context and given the timescale of future missions [Boccaletti et al., Baudoz et al.]

3 A. Boccaletti Pasadena, Sept th MIRI Performance (examples) Evaluate sensitivity to : - pupil shear - pointing offset - defocus Develop a model :- telescope & aberrations - planetary spectra differential pointing : 0mas differential pointing : 5masdifferential pointing : 10mas differential pointing : 15mas

4 A. Boccaletti Pasadena, Sept th SPHERE - 2nd generation instrument at VLT (ESO) [Beuzit et al.] - stands for Spectro-Polarimetric High contrast Exoplanet REsearch - study of EGPs around nearby stars and in young associations down to 0.5-1M J - combination of 3 instruments- IR camera Dual Band Imaging IRDIS - IR Integral Field Spectrograph IFS - Vis. camera Dual Polarisation ImagingZIMPOL - AO high order correction (40x40 actuators), high stability, static error compensation - IR coronagraphs : - Lyot - apodized Lyot - achromatic phase masks SPHERE capabilities rely on differential imaging (spectral or polarimetric)

5 A. Boccaletti Pasadena, Sept th SPHERE Simulator based on CAOS [Carbillet et al.] Developed for a full system analysis, not only coronagraphs 1. put specs. on the system : - AO related parameters - PSD and amplitude of phase aberrations upstream the coronagraph - pointing alignment (accuracy, reproducibility) - pupil centering (accuracy, reproducibility) - focus stability - chromatic aberrations upstream/downstream coronagraph - comparison of coronagraphs and optimization of each design - sensitivity of spectral differential imaging w.r.t. filters width and separation - detector related parameters (Flat Field) - and many others … 2. once specs are defined => derive performance function of astrophysical parameters (Sp, dist., age, planet mass, planet model, …) 3. provide input to the Exposure Time Calculator A very useful TOOL to study the whole system and sub-systems Can be adapted to other projects

6 A. Boccaletti Pasadena, Sept th Some results [Boccaletti et al.]

7 A. Boccaletti Pasadena, Sept th Some implications for TPF-C 1. WF active control vs. Calibration - WF control needs long integrations to sense at the level (as long as detection) - snr, convergence for iterative techniques - several images for global techniques [Bordé et al.] - stability issues (system and active element) - Calibration (differential imaging) is starting from a higher level ( ) - speckle noise is reduced after the calibration - long integrations to reduce photon noise - dedicated image processing - stability is required but no active elements (critical for space mission) 2. Coronagraphy - so many corono. that a comprehensive comparison becomes difficult - studies have to be more system oriented optical quality, coatings & ghosts, phase, positioning accuracy, stability, chromaticity, out of band flux, polarization, … detector artifacts (FF, remanence, smearing, …) - can we make it, at which level of accuracy ??? Some trade offs and evaluation of systematics are needed …

8 A. Boccaletti Pasadena, Sept th a few more words on calibration … Calibration may allow lower constraints on the - coronagraph performance (a /10 -7 raw contrast instead of / ) - coronagraph manufacturing defects - IWA and stellar leakage - optical quality (PSD and amplitude of phase defects) - chromaticity - … - Report these constraints on the calibration unit (might be easier) - The underlying point is that Signal to Noise is THE parameter to considered in TPF-C - CALIBRATION has to be CONSIDERED in TPF-C thoroughly What is the best calibration concept for TPF-C ?: spectral : polarisation : coherence Probably, WF control and Calibration will have to be combined at some point

9 A. Boccaletti Pasadena, Sept th Toward collaboration … We are talking about US/EU collaboration for years. Workshops were organized : - Leiden Workshop, Villefranche IAU, this workshop, other to come hopefully … Collaboration not very concrete so far !!! Why ? Space agencies do not always share the same views …. (but don’t say it) But, SCIENCE must remain the driver of any projects !!! we all agree that the complementarity Vis/IR, corono/interfero is crucial for the study of telluric planets. At some point NASA/ESA will have to collaborate for a coronagraphic mission (like for HST, JWST, TPF-I, …) Can we push agencies to collaborate …. Probably, if we do so … How ? - combine efforts : initiate international strategy for development of coronagraphs and wavefront sensing in order to address some critical points in a coherent way - share expertise - share facilities (optical benches) within some sort of network - investigate manufacturers in an international way - collaborate on publications collaborate through Students, Postdocs