Tim Healy

Tony Perry

Planet Survey Mission

IntroductionFinding Planets• Pulsar Timing• Astrometry• Polarimetry• Direct Imaging• Transit Method• Radial VelocitySelecting Planets• Recap• What else do we want to know?Proposed Plan

Outline

Introduction

(NASA)

Finding Planets

Pulsar Timing MethodFirst exoplanet confirmation! (1992)Poor candidates for life

Wolszczan and Frail, 1992

• Precisely measure a star’s position over time

• Mutual center of mass (barycenter)• Successful in characterizing binary

star systems• Inaccurate claims of ‘unseen

companions’• Not useful unless planet is massive• Good as a complementary

technique

Astrometry

• Un-polarized starlight• When the light reflects of a

planet’s atmosphere, it becomes polarized by interacting with the molecules in the atmosphere

• Analyze light in search of polarization

• No planets found using this method

Polarimetry

University of Hertfordshire

Land-Based Direct ImagingTechnological Aspects• Larger Mirrors• Atmospheric Distortions• Adaptive Optics (e.g. Keck)• Glare from host star • Coronograph (e.g. Gemini Planetary Imager)• > 5 AU• Optical and Near IR spectraResultsPotentially useful for finding life

Keck II w/laser guide (CASA)

Simulation of Coronograph, (GPI)

• Difficult to directly detect planets (extremely faint light sources)

• Low Earth orbit in 1990• View the near ultraviolet, visible,

and near infrared• Outside the distortion of Earth’s

atmosphere (no background light)• Ultra-Deep Field image

• 2006 - Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS)• 16 extrasolar candidate planets

discovered• When extrapolated, strong

evidence of about six billion Jupiter-sized planets

Direct Imaging – Hubble Telescope

http://www.youtube.com/watch?v=HAWMa_YEuKI

(NASA)

Dip in flux ~10^-5Space-basedMass, period• T, habitability

Transit Photometry Method

(NASA)

http://www.youtube.com/watch?v=vjdxJQj4QHY

Transit Method (Kepler Mission)Looking for terrestrial planets in habitable zonesLaunched 3/7/2009Solar neighborhood-like regionOrbit:• Earth-trailing, (372.5 days)•Off-ecliptic6 year mission• 3 transits for significanceFollow-up ObservingGood start to look for life Kepler (NASA)

2321 candidates around 1790 stars61 confirmed

(2/27/12)

2321 candidates around 1790 stars61 confirmed

(2/27/12)

Blue are habitable candidates48 canidates1 confirmed (Kepler 22b)

• Similar to Astrometry• Radial velocity calculated from

displacement in parent star’s spectral lines due to the Doppler effect

• Modern spectrometers can detect velocity variations 1 m/s or less• High Accuracy Radial Velocity

Planet Searcher (HARPS) • Most productive planet hunting

technique by far• When used in combination with

the Transit Method, the planet’s true mass can be estimated

Radial Velocity (Doppler Spectroscopy)

• Surveyed 102 red dwarfs• Thought to make up ~80% of the stars in our galaxy• 40% of all red dwarf stars have a super-Earth orbiting the

habitable zone• Estimated tens of billions of these planets exist within the

Milky Way• Stellar eruptions, flares

Radial Velocity - HARPS

msnbc - Artist rendition of sunset on super-Earth Gliese 667 Cc

Selecting Planets

Compiled ResultsCatalog of planets (mass, period, host star)

Lunine et al., 2009

Open QuestionsRocky or gas giantAtmosphereOrbit stabilityPresence of:• Water• Methane• Carbon Dioxide• Plate Tectonics• Satellite(s)

Proposed Plan

• Astronomer median annual wage: $95,500

• Mission cost: $1 mil per year

• Utilize two most productive planet searching techniques• Transit Method (Kepler)• Radial Velocity (Doppler)

• Kepler - mission cost for entire life cycle is ~$600 million

• Doppler - ESO 3.6 m telescope cost is $41.7 million (HAPRS was installed in 2002 on this telescope)

• James Webb Space Telescope – 2018 launch date

• ELT, first light 2020s

Proposed Plan

Questions?