1 / 25

A STEP

A STEP. Antarctica Search for Transiting Extrasolar Planets. Kick-off meeting Nice, September 5-6, 2006. Programme. Participants. 20. 17. Tonight, 20h. Programme. The future of transit searches.

ely
Download Presentation

A STEP

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A STEP Antarctica Search for Transiting Extrasolar Planets Kick-off meeting Nice, September 5-6, 2006

  2. Programme

  3. Participants 20 17

  4. Tonight, 20h

  5. Programme

  6. The future of transit searches Combined to radial-velocimetry, it is the only way to determine the density, hence the global composition of a planet Transit spectroscopy offers additional possibilities not accessible for “normal” planets We foresee that exoplanetology will have as its core the study of transiting exoplanets examples: A correlation between the metallicity of stars and planets (Guillot et al. A&A 2006) Stellar formation model constraints (Sato et al 2005)

  7. Exoplanets: present lessons • Exoplanets are relatively frequent: • About 10% of solar-type stars possess planetary companions detectable by radial velocimetry • That represent numerous targets: at least 100000 planets companions to stars with magnitude mv<=12.5.

  8. Exoplanets: present lessons The number of transiting giant planets in the sky can be estimated from radial velocity measurements. • Number of transiting giant planets in the sky: about 200 around stars with magnitudes < 10.5 • Strong interest in detecting transits • of small planets • of a very large number of planets • around bright stars • Limitations of transit surveys are still not well understood (red noise).

  9. The future of transit searches • 2 future milestones: • COROT: 60 000 stars (nominal mission), mv=11 to 16, for 150 days, launch oct. 2006 • KEPLER: 100 000 stars, mv=11 to 14 for 4 years, + 70 000 for 1 year, launch end 2008 • Limited by data transmission to Earth • A problem for the detection of small planets: background eclipsing binaries • Future missions should: • Detect more planets • Diversify the targets • Detect smaller planets • from SPACE • Natural but costly • Limited in telescope size, number of instruments... • from DOME C • Promising but uncertain • Requires precursor mission(s)

  10. Why transit searches at Dome C? • Continuous night for 3 months • Excellent weather • Questions: • We don’t know how the following factors will affect transit surveys: • Sky brightness & fluctuations • Presence of the moon • Generally, systematics effects due to the combination of astrophysical, atmospheric and instrumental noises • Technical problems • Autonomous operations in cold (-50°C to -80°C) conditions • Temperature fluctuations • Icing • Electrical discharges

  11. A STEP: the philosophy behind • Prepare future photometric projects for planetary transit detection at Dome C • Use available equipment, minimize development work for a fast implementation of the project • Directly compare survey efficiency at Dome C with other surveys (e.g. BEST 2 in Chile for the same target field)

  12. A STEP Objectives Determine the limits of Dome C for precise wide field photometry (Scintillation and photon noise … or other noise sources ?) If the site is competitive with space and transit search limits are well understood, establish the bases of a mid-term massive detection project (large Schmidt telescope or network of small ones) Search for transiting exo-planets and characterization of these planets – Detection of bright stars oscillations.

  13. With a “classical” survey, only the “stroboscopic” planets are detectable ! Continuous observations • A good phase coverage is determinant to detect the large majority of transits from ground • OGLE: transits discovered • really short periods P ~ 1 day (rare !) • stroboscopic periods • Hot Jupiters: periods around 3 days, depth ~1% Probability of detection of a transit for a survey of 60 days With OGLE For the same telescope with a permanent phase coverage

  14. Observing at dome C – Lessons from the first two winter campaigns (1) An exceptional phase coverage … • Confirmation by the first winter campaign of the exceptional phase coverage (cloud coverage, austral auroras) « First Whole atmosphere night seeing measurements at Dome C, Antarctica » Agabi, Aristidi, Azouit, Fossat, Martin, Sadibekova, Vernin, Ziad • Environmental systematic effects considerably reduced: • air mass • timescale of environmental parameters evolution • Expectations for future transits search programs • low scintillation

  15. Observing at dome C – Lessons from the first two winter campaigns (2) … But a lot of technical difficulties to take into account • Frost – different Behaviour for different telescopes • Differential dilatations inside the telescope • Telescope mounts misfunctioning at really low temperature

  16. THE A STEP TEAM

  17. THE A STEP TEAM

  18. THE A STEP TEAM

  19. THE A STEP TEAM

  20. A STEP Telescope A STEP Characteristics: Camera use: Defocused PSF PSF sampling: FWHM covering ~4 pixel Time exposure: 10s Readout time: 10s Telescope mount: German Equatorial Astrophysics 1200 With controlled heating Pointing precision tolerated ~.5” Data storage: ~500 GB /campaign Data retrieval at the beginning of Antarctic Summer for first campaigns CCD DW 436 (Andor) Size 2048 x 2048 Pixel size 13.5 mm 1.74 arcsec on sky

  21. A STEP Camera : Andor DW436 • 2048x2048 pixel • Backwards illuminated CCD • Limited intra-pixel fluctuations (Karoff 2001) • Excellent quantum efficiency in red • -USB2 with antarctisable connection • -Performances guaranted by constructor

  22. A precise photometric telescope at Dome C Telescope tube: INVAR structure With Carbon fiber coverage • Specific devices under study : • External screen for flatfields • Temperature stabilization • Controlled heating for mobile parts • Antarctized connections • Redundant data storage facility • Semi-automatical Thermal enclosure for focal instrumentation 4Mpixel DW436 CCD Wynne Corrector

  23. Status • Fully funded (OCA/LUAN/OAMP): • Agence Nationale de la Recherche (yet to come) • 2006-2009 (3 years) • Commission Specialisée Astronomie (INSU) • Camera (2006) • Programme National de Planétologie • Phase 0 (travel)

  24. Schedule of A STEP

  25. Goals of this meeting • Learn from other experiences • Converge on scientific specifications • Define instrumental specifications • Choose telescope, mount & camera • Define working packages

More Related