A Search for Habitable Planets DK 10/07 Finding Habitable Planets The Kepler Mission David Koch NASA Ames Research Center

A Search for Habitable Planets DK 10/07 OVERVIEW 2 Scientific Goals Mission Requirements Kepler Star Field Follow-up Observing Expected Results Photometer Science Team Status

A Search for Habitable Planets DK 10/07 3 What is it we are looking for? Planets form out of a disk of gas and dust left over from star formation. If mass too small, less than about 1/2 M   then it can’t hold onto a life sustaining atmosphere (Mercury, Mars) If mass too big, greater than about 10 M   then it can hold onto the very abundant light gases (H 2 and He) and turn into a gas giant (Jupiter, Saturn, Uranus, Neptune) So, to find habitable planets we need … a system capable of finding Earth-size planets (0.8<R  <2.2) And, is able to find them in the habitable zone, i.e., in an orbit where liquid water can exist on the surface of the planet. Copyright Lynnette Cook D ERIVING THE S CIENTIFIC R EQUIREMENTS Kepler is specifically designed to search for habitable planets (0.5 to 10 M  ) in the HZ (near 1 AU for solar-like stars)

A Search for Habitable Planets DK 10/07 Kepler G OALS 4 Explore the structure and diversity of extra-solar planetary systems 1.Determine the frequency of terrestrial and smaller planets in or near the habitable zone of a wide variety of spectral types of stars; 2.Determine the distributions of size and semi-major axis of these planets; 3.Estimate the frequency and orbital distribution of planets in multiple- star systems; 4.Determine the distributions of semi-major axis, albedo, size, mass and density of short-period giant planets; 5.Identify additional members of each photometrically discovered planetary system using complementary techniques; and 6.Determine the properties of those stars that harbor planetary systems.

A Search for Habitable Planets DK 10/07 Current State of Affairs Finding Earth-size planets in the HZ is well beyond current capabilities Note: Masses are only lower limits except for transit cases and statistically about 2x greater than shown

A Search for Habitable Planets DK 10/07 6 The Kepler approach to detecting planets is to measure the change in brightness of stars caused by planetary transits To measure 80 ppm, you need to be above the Earth’s atmosphere The probability for alignment is about 0.5% for an Earth-like orbit So… you need to observe lots of stars 3.5+ yr mission is required to detect at least 3 transits preferably 4 Must be robust to false positives: Able to reject background eclipsing binaries, grazing binaries and require repeatable transit depth, duration and temporal separation Jupiter: 1% area of the Sun Earth or Venus 0.008% area of the Sun (80 ppm) What Are The Design Requirements ?

A Search for Habitable Planets DK 10/07 7 T HE M ISSION D ESIGN Photometric precision of 20 ppm 4  for V=12 solar-like star in 6.5 hours Continuously and simultaneously monitor 100,000 solar-like stars A one-meter aperture Schmidt telescope field of view >100 deg 2 A focal plane array of 42 CCD with a total of 95 mega-pixels Launch into an Earth-trailing orbit to permit continuous viewing Observe same star field for 3.5+ years Analyze data for a sequence of transits

A Search for Habitable Planets DK 10/07 S TAR F IELD IN C YGNUS The Kepler star field is a part of the extended solar neighborhood in the Cygnus-Lyra regions along the Orion arm. It is located on one side of the summer triangle (Deneb-Vega-Altair)

A Search for Habitable Planets DK 10/07 Follow-Up Observing Plan 9 1. Cross check for internal consistency of Kepler data a. Individual transits consistent in amplitude and duration b. Individual pixels of psf consistent within statistics for each cadence c. Differential Image Analysis not show shift in position 2. Check catalogs for nearby stars, background eclipsing binary 3. Perform moderate resolution spectroscopy a. Eliminate white dwarf or grazing eclipsing binary b. Improve knowledge of mass and size of the parent star 4. Perform high-precision radial-velocity observations with HIRES, HET and HARPS-North: a. Measure mass or upper limit to mass (get density) b. Detect companion non-transiting giant planets in system

A Search for Habitable Planets DK 10/07 Follow-Up Capability of HARPS-North 10 Mass uncertainty for HARPS-North assuming a non-active, slowly-rotating G2V star with V=12, 50 hours of observing optimized for the known period and phase

A Search for Habitable Planets DK 10/07 E XPECTED R ESULTS 11 What will Kepler Mission discover? Planets with sizes from that of Mars to Jupiter with orbital periods from a few days up to two years Can expect 100’s to 1000’s of ??? size planets depending on frequency ???, stellar type and orbit ??? About 600 terrestrial planetary systems if most have orbits like Earth (M < 10 M  ) About 50 transiting short-period giant planets based on their already known frequency A NULL result would also be very significant ! Also… Astrometric distances to Kepler stars (derive size) Astereoseismology for about stars (derive mass)

A Search for Habitable Planets DK 10/07 Photometer Components Dust Cover 1.4 m Primary Mirror Focal Plane Radiator Sunshade Lower Telescope Housing Focus Mechanism Assy (3) CCD Detectors (42) Focal Plane Array Assbly Upper Telescope Housing 0.95 m Schmidt Corrector Aft Bulkhead

A Search for Habitable Planets DK 10/07 S CIENCE T EAM William Borucki, Science Principal Investigator, NASA Ames Research Center David Koch, Deputy Principal Investigator, NASA Ames Research Center Co-Investigator’s Working Group G. BasriUC-Berkeley T. BrownLas Cumbres Obs Global Tel J. Christensen-Dalsgaard U. Aarhus (Denmark) W. CochranMcDonald Obs./U. Texas E. DeVoreSETI Institute E. DunhamLowell Observatory T. N. GautierJPL J. GearySAO R. GillilandSTScI A. GouldLawrence Hall of Sci/UC-B J. JenkinsSETI Institute Y. KondoNASA/GSFC D. LathamSAO J. LissauerNASA/ARC Science Working Group N. BatalhaSan Jose State University A. BossCarnegie Institute of Washington D. BrownleeUniversity of Washington D. CaldwellSETI Institute J. CaldwellYork University (Canada) A. DupreeSAO S. HowellNat’l Optical Astronomy Observ. G. MarcyUC-Berkeley D. MorrisonNASA/ARC T. OwenUniversity of Hawaii H. ReitsemaBall Aerospace D. SasselovHarvard University J. TarterSETI Institute M ANAGEMENT T EAM Leslie Livesay, Project Manager at Jet Propulsion Lab Alan Frohbieter, Program Manager at Ball Aerospace, Boulder, CO

A Search for Habitable Planets DK 10/07 Status 14 Recent program pressures forced, among other things, a decrease in mission life from 4 to 3.5 years. But the capability still exists to extend the mission life. Completed environmental testing and characterization of focal plane array (42 CCDs and electronics). Telescope is ready. Currently performing spacecraft and photometer assembly. Flight software has finished qualification testing Integration of photometer and spacecraft to begin in the Spring of 2008 Launch is scheduled for Feb Plan is to operate for 3.5+ years 2009 will be the 400 th anniversary of Kepler’s publication of Astronomia Nova describing his first and second laws of planetary motion and it is the International Year of Astronomy

A Search for Habitable Planets DK 10/07 Summary 15 The Kepler Mission is… NASA’s first mission capable of finding Earth-size and smaller planets in the habitable zone of other stars.