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LIVE INTERACTIVE LEARNING @ YOUR DESKTOP NASA: How to Become a Planet Hunter: Careers in Space Science Presented by: Dr. Stephen Edberg May 24, 2012 Exoplanet Discovery and Exploration: Expanding Geography Outside Our Solar System Stephen J. Edberg Exoplanet Exploration Directorate NASA Jet Propulsion Laboratory California Institute of Technology There are 200 billion stars in our galaxy… …one of them is our Sun. The Sun has eight (or nine) planets… …we know of one that has life. What about elsewhere? There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Stars are a billion times brighter… …than the planet …hidden in the glare. Like this firefly. Planet Discovery Methods • Direct Imaging (Vis & IR) • Radial Velocity • Transits • Gravitational Microlensing • Astrometry • Pulsar Timing Planets by Direct Imaging Radial Velocity - 1 NO Radial Velocity - 2 BLUE Radial Velocity - 3 RED Radial Velocity - 4 Single Line “Binary” - Planet Planets by Radial Velocity: Actual Observation Method Star Spectrum Iodine Spectrum 540-775 nm Single Line “Binary” - Planet Planets by Radial Velocity Without Iodine Cell Planets by Transit - 1 Planets by Transit - 2 Kepler Spacecraft Transit Geometry Starlight passing through the planet’s atmosphere. z T( z, ) By observing the spectrum of the star + planet as the planet transits, we can determine the height of the atmosphere where it becomes opaque and determine its chemical composition. Traub 19 Transit/Occultation Weather Map There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Gene Serabyn There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Diana Blaney There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Ara Chutjian There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Jan & Paul Chodas There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Jeanne M Holm There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Sanjoy S Moorthy There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Leslie L Lowes There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Carolina Carnalla-Martinez There is a role for everyone who wants to be a part of this great exploration. Contributors include: astronomers planetary scientists physicists mathematicians computer scientists engineers artists educators public affairs officers business managers and others Joanne Kennedy What We Know What We Want to Know • About Planets • About Planetary Systems Knowledge and Ignorance of Extrasolar Planets What we do know – Giant planet occurrence is high: ~7% – Mass distribution extends to near Earth’s mass – Eccentric orbits are common: scattering? – Many multiple systems of giant planets are known What we don’t know – Existence of terrestrial planets Are there low-mass planets in the ‘habitable zone’? Super-Earths certainly. – Mass distribution of planets is incomplete and has strong selection effects What about spectral type? Stellar age? Evolutionary state? Planetary Systems: Questions Statistics of planetary systems – How common are planetary systems? – Are certain star types favored? – What is the distribution of planetary systems in the Galaxy? Characterizing planetary systems – What are the orbit radii? – Are the orbits circular or eccentric? – Are multiple-planet systems common? For multiple planet systems – What is the typical mass distribution of planets in a system? – What is the typical radius distribution? – Are the orbits co-planar? Must have astrometry to answer this – Are the planets’ orbits stable? ? What We Want to Know • About Planets • About Planetary Systems How do we find out? You can help us! Planets by Stellar Wobble Small planet Massive planet Principle of Astrometric Planet Detection How Much Wobble? It can be measured with an accuracy of about 1 μas (quite a bit thinner than the line plotted here). “The wobble effect”: our Solar System as seen at 10 pc distance • 1 tick mark = 200 µas • Sun-Jupiter wobble = 500 µas • Sun-Earth wobble = 0.3 µas Ordinary Telescope – Optical, IR, Radio An ordinary telescope collects electromagnetic radiation, forms an image which is then analyzed to determine the nature/position of the object in the field of view. Telescope Telescope Resolution Sensitivity /D detector = wavelength diameter (D) Airy Disk D Michelson Stellar Interferometry An interferometer combines the light from two or more small telescopes (Mersenne) to yield the angular resolution of a much larger telescope. Interferometer Resolution Interferometer /B = wavelength Telescope (d) Combiner & Telescope (d) detector baseline (B) Fringe Pattern Sensitivity (2*d*B) SIM Lite could have made measurements precise enough to find Earths orbiting other stars. But What Is a Habitable Planet? A good planet is: Not too big Not too small Not too hot or too cold New spacecraft will be able to find planets similar in mass to Earth, at the “right distance” from their host stars. We can study them with advanced telescopes like... Terrestrial Planet Finder – Interferometer (TPF-I) International TPF-I / Darwin: Emma X-Array Terrestrial Planet Finder – Coronagraph (TPF-C) Jupiter Earth Images from 3 Types of Coronagraph Terrestrial Planet Finder – Occulter (TPF-O) Planet Target Star NWD Starshade JWST • Big telescope (planet is faint!) • Big occultor (few times size of telescope) • Big separation (to see close to star) 42 Color Gives a First Impression of a Planet Solar system planets have colors that label them by type. Planet spectra Blue (0.4-0.6 m), Green (0.6-0.8 m), Red (0.8-1.0 m) Vegetation as a Surface Biosignature Visible photo Near-infrared photo S. Seager TPF Investigations The TPFs can distinguish between planets... Searching for Other Earths You can search for other Earths if you • Want to explore new worlds. • Read and learn as much as you can in the subject that interests you. • Learn to share your ideas clearly in writing. Searching for Other Earths http://planetquest.jpl.nasa.gov/ and, for my Aliens vs. Editor blog, http://planetquest.jpl.nasa.gov/ave Thank you to the sponsor of tonight's Web Seminar: This web seminar contains information about programs, products, and services offered by third parties, as well as links to third-party websites. The presence of a listing or such information does not constitute an endorsement by NSTA of a particular company or organization, or its programs, products, or services. National Science Teachers Association Gerry Wheeler, Interim Executive Director Zipporah Miller, Associate Executive Director Conferences and Programs Al Byers, Assistant Executive Director e-Learning NSTA Web Seminars Paul Tingler, Director Jeff Layman, Technical Coordinator Brynn Slate, Program Coordinator LIVE INTERACTIVE LEARNING @ YOUR DESKTOP