The Search for Habitable Worlds Lecture 3: The role of TESS

Transcription

1 The Search for Habitable Worlds Lecture 3: The role of TESS David W. Latham Lucchin PhD School, Asiago, 26 June 2013

2 A aaaaaaaa Dave Latham, Science Director, CfA AAAAAAAAAAAA Selected for launch in 2017

3 Geneology of TESS 2006: Proposal to monitor bright stars for hot Jupiters Mission of opportunity to re-use the HETE-2 optical camera 2007: Re-structured as a privately-funded small mission Efforts to convince donors failed 2008: Re-configured as a NASA Small Explorer (SMEX) Selected for Phase A (1 of 3 Astrophysics Missions) GEMS won the selection ($104M cap) 2010: Re-proposed as a NASA Explorer ($200M cap) Selected for Phase A (1 of 2 Astrophysics Missions) 2013: Selected for formulation (April 5, 2013) Innovative orbit for continuous light curves (video on U-Tube) Launch scheduled for 2017 Discovering New Earths and Super-Earths in the Solar Neighborhood 3

4 TESS and Kepler Answer Different Questions TESS: Where are the nearest transiting rocky planets, the best for characterization? Kepler: How common are true Earth analogs? Discovering New Earths and Super-Earths in the Solar Neighborhood

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7 TESS targets are 30 to 100 x brighter than Kepler targets

8 Blue = 3+ transits Red = 2 transits

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10 TESS Ground-Based Facilities TESS photometry DETECTION 5000 Transit-like Signals LCOGT, MEarth, KeplerCam, Euler 2000 Survive Direct Imaging LCOGT, TRES, McDonald, Euler, OHP, CARMENES, HARPS and HARPS-N 500 Survive Reconnaissance Spectroscopy 100 VALIDATION Selected for Precise Doppler Spectroscopy 50 Measured masses

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12 Predicted Science Yield from TESS Mission TESS Will Discover ~300 Earths & Super-Earths Discovering New Earths and Super-Earths in the Solar Neighborhood 12

13 Payload Overview Four identical wide-field CCD imaging cameras Straightforward optical design Cameras passively cooled in a stable thermal environment Heritage MIT/LL focal plane array SEAKR Data Handling Unit (DHU) FPGA front-end processors select & stack postage stamps around target stars Discovering New Earths and Super-Earths in the Solar Neighborhood 13

14 TESS Wide FOV CCD Camera Detector Assembly Lens Assembly Lens Hood Characteristic Value Effective Area 60 cm 2 Lens Focal Ratio 1.6 CCD Focal Plane Array (Frame Store Mode) 2K x 2K pixels 15 µm/pixel Lens Focal Length 154 mm Camera FOV 23 x 23 Discovering New Earths and Super-Earths in the Solar Neighborhood 14

15 CCD Package & Focal Plane Array Photos TESS Prototype Package & CCID47 TESS CCD package derived from qualified designs: NASA WFIRST ESA EUCLID Prototype FPA identical to flight FPA Identical SiC material and vendor NASA WFIRST/ESA EUCLID TESS Prototype FPA Discovering New Earths and Super-Earths in the Solar Neighborhood 15

16 TESS Prototype Cameras Prototype Unit #2 Vibration demonstration Detector simulator GEVS Workmanship Prototype Unit #1 Thermal demonstration Operational detector Thermal vacuum at operational temperature Discovering New Earths and Super-Earths in the Solar Neighborhood 16

17 Polychromatic TESS and Kepler PSFs Compared TESS -75 C (Prototype Lens + CCDs) 12 Off-Axis On-Axis Kepler PSFs (Flight Optics & CCDs) 7 Off-Axis On-Axis PSF = Point Spread Function Discovering New Earths and Super-Earths in the Solar Neighborhood 17

18 TESS Enables Atmospheric Characterization TESS will identify the best and smallest exoplanet targets for characterization of atmospheres using: JWST Extremely Large Telescopes (ELTs) Future Exoplanet Explorers, Probes, and Large Missions Discovering New Earths and Super-Earths in the Solar Neighborhood 18

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20 NOT FLWO Spectroscopic Follow-Up of Kepler Objects of Interest Lars Buchhave & Dave Latham and the Kepler Team Lick McDonald

21 Role of Recon Spectroscopy Help identify astrophysical false positives involving eclipsing binaries Provide improved stellar parameters for more accurate host star mass and radius Spectroscopic T eff, log(g), [m/h], V rot, V rad Derive M star, R star, age from stellar models Asteroseismology needs T eff and [m/h]

22 Because planets orbit stars, stellar astronomers are useful again! (especially old stellar spectroscopists)

23 Stellar parameters from spectra MOOG - Sneden SME Valenti, Piskunov, Fischer MOOG and SME require high SNRe (~100) SPC (Stellar Parameter Classification) Same results as SME at lower SNRe (~30) Buchhave extension of Carney et al 1987 Uses CfA library of calculated spectra

24 HD with FLWO TRES; one of 49 echelle orders Red is the best match model spectrum, blue is the observed spectrum

25 KOI 210 with the McDonald 2.7-m coudé: V=15.1 mag

26 3-dimensional fit to stellar parameters

27 [m/h] for Kepler Objects of Interest Take advantage of thousands of recon spectra Select strongest exposures, CCF > stars hosting 226 planet candidates Compare [m/h] as function of planet size No attempt to derive absolute occurrence rates No correlations with other parameters found

28 Metallicity versus Planetary Radius

29 226 Planets around 156 Stars