# Presentation: 108867

## Exoplanet Task Force

- A Strategy for the Detection and Characterization of Exoplanets
*Preliminary Findings Briefing*

- “Do there exist many worlds, or is there but a single world? This is one of the most noble and exalted questions in the study of Nature.”
*-Albertus Magnus *
*1193-1280*

## Outline

- Introduction to the Taskforce
- Recent Exoplanet Highlights
- Major Recommendations
- Recommended Strategy

## Task Force Membership

| Debra Fischer
San Francisco State  | Gary Melnick
CFA |
| --- | --- |
| Heidi Hammel
Space Science Institute | David Monet
USNO |
| Lynne Hillenbrand
Cal Tech | Charley Noecker
Ball |
| James Kasting
Penn State | Stan Peale
UCSB |
| Greg Laughlin
UCSC | Andreas Quirrenbach
Landessternwarte Heidelberg |
| Bruce Macintosh
Lawrence Livermore | Sara Seager
MIT |
| Mark Marley
NASA Ames | Josh Winn
MIT |

- Jonathan Lunine (chair) - LPL/University of Arizona

- Thomas Henning - MPI (ESA liaison)

## Task Force Process 

- Five Task Force meetings in 2007
- Public Input
- 18 external presentations
- 84 exoplanet white papers contributed from the community
- Open sessions during the first 4 meetings
- 7 external readers
- Report is being completed

## Publications and Planets

## Recent Exoplanet Highlights

- Many detections with different techniques
- Rich variety of exosystems
- Multi-planet systems
- Closer to solar system analogs
- Lower masses
- Super Earths orbiting M stars may be common
- Atmosphere studies with Spitzer

## Outline

- Introduction to the Taskforce
- Recent Exoplanet Highlights
- Major Recommendations
- Recommended Strategy

## Compelling Questions Identified by the Task Force

- What are the characteristics of Earth-mass/Earth-size planets in the habitable zone around nearby, bright stars?
- What is the architecture of planetary systems?
- How do planets and planetary systems form?

## Recommendations: Towards Earths

**Intensify RV studies to reach down to (several) Earth-mass planets around bright stars**
- More telescope time/higher precision
- Invest in IR spectrograph development for late M stars
**Search for transiting terrestrial-size exoplanets around nearby M dwarfs and characterize with Warm Spitzer and JWST**

## Depth of Search Figures

- The number of detectable planets assuming every star to be examined has a planet of the given mass and semi-major axis
- No assumptions need be made about planet distributions
- No imposed mission lifetime
- Scaled x-axis allows all star types on the same plot
- Both x- and y-axes are on a log scale

## RV Studies

- Optical

- Near IR

## Terrestrial Transits for Characterization

- Transits from space

- Atmospheres with JWST

## Recommendations: Towards Earths

**Develop a space-borne astrometric planet search mission**
- Mass and orbits are required to understand habitability
- Find the Earth-mass exoplanets in habitable zones of nearby sun-like stars and get their orbits
- Sub microarcsecond astrometric signatures on order of 100 stars
- Study planetary architectures whether or not Earth-mass planets are common, whether or not zodi is large
**Prepare for space-based direct imaging characterization mission**
- Ongoing development to be ready for launch after some targets are known
- Exozodi measurements down to 10 zodi around nearby stars

## Space Astrometry and Direct Imaging

- Space Astrometry and Direct Imaging

## Recommendations: Planetary Architectures/Formation

**Microlensing for planetary masses and separations **
- Augment ground-based facilities
- Space-based mission if possible at Discovery level or below, if does not affect the astrometric and direct imaging missions
**Ground-based direct imaging**
- Develop and implement extreme AO
- Support construction of a 30-m telescope with extreme AO

## Space-Based Microlensing

## Kepler

## Ground-Based Direct Imaging

## Recommendations: Planetary Architectures/Formation

**Circumstellar Disk Science**
- Maintain US involvement in Herschel and ALMA
- Archival analysis for relevant Spitzer, Chandra, Hubble, and ground-based data
- Invest in appropriate instrumentation on large-aperture telescopes
**Support for activities that maximize the knowledge return from data and train new scientists in the field**
- Theoretical studies
- Stellar property surveys
- Competitive fellowships for young researchers

## Outline

- Introduction to the Taskforce
- Recent Exoplanet Highlights
- Major Recommendations
- Recommended Strategy

## Definition of 

- The fraction of stars that have at least 1 potentially habitable planet
- I.e., at least one planet in the habitable zone
- For our sun,  = 1

- From TPF-STDT report 2005

## Strategic Goals

- To a high degree of statistical significance, will be determined around a broad range of main sequence stellar types.
- The architectures of planetary systems, both in the nearby solar neighborhood of order 106 cubic pc, and in the larger galactic bulge, will be constrained down to sub-Earth masses for semi-major axes out to several AU (for G-dwarfs)
- Provided  is large (at least 0.1), at least one Earth-sized planet will have its mass and basic atmospheric composition characterized

- Division into three time periods
- 1-5, 6-10, 11-15 years from now

## Two-Pronged Strategy

- 5-10 yrs

- 10-15 yrs

- Fast-track
- ground-based, and existing space assets

- Requires technology investments
- And new space-based facilities

- Prong 1: M dwarfs

- Prong 2: F, G, K dwarfs

## If   is > 0.1

- 5-10 yrs

- 10-15 yrs

-         ,masses, addresses   Density, detectability      Characterize for habitability

- M dwarfs

- F, G, K dwarfs

- Density, addresses                   Characterize for habitability

- Exo-zodi studies

- If   is > 0.1

*RV  +  Transit surveys--*> Spitzer-->JWST

- Corot/ Kepler   *--*> Astrometry+RV  --> Space Direct Imaging

## If   is < 0.1

- 5-10 yrs

- 10-15 yrs

-         ,masses, addresses   Density, detectability

- M dwarfs

- F, G, K dwarfs

- Planetary Architecture

- Exo-zodi studies

- If   is < 0.1

*RV  +  Transit surveys*

- Corot/Kepler              Astrometry
-                                 Microlensing             Larger space-				          		based direct
- 						imaging in future

- Ground-based EXAO on ELT for giant planets

## If  Exozodi > 10 Earth Zodi

- 5-10 yrs

- 10-15 yrs

-         ,masses, addresses   Density, detectability      Characterize for habitability

- M dwarfs

- F, G, K dwarfs

- Planetary architecture

- Exo-zodi studies

*RV  +  Transit surveys--*> Spitzer-->JWST

- Corot/ Kepler   	Astrometry

- Microlensing

- Ground-based EXAO on ELT for giant planets

**Notes:**
A 

We always 14
A 37

## 1-5 yrs

- 5-10 yrs

- 10-15 yrs

-    Advanced and intensive RV studies - Kepler followup
-                  Advanced ground-based microlensing
-                                Advanced ground-based transit searches
-                                                              ELT advanced imaging (extreme AO)
- Fellowships, supporting observational and laboratory science, theory

- Technology development

- Discovery Microlensing Mission

- Spitzer transit followup

- JWST transit followup

- Kepler

- Astrometric mission

- IR Characterization

- Visible Characterization

- Exozodi characterization

- Ground-based

- Existing Missions

- Proposed Missions

- Recommended Programs, Missions and Activities

## Strategy Summary

**Two-pronged approach**
- Potential for early results on Earth-sized planets orbiting M stars
- Astrometric search is insensitive to zodi and background objects; ensures significant results on planetary architectures and Earth-mass planets
- Known targets simplify the space-based direct detection mission
**Flexibility**
- Decision points occur early enough in the strategy to shift focus toward the end, contingent on and zodi
- Individual elements can be delayed or stretched out while the overall program still provides exciting discoveries

**The plan addresses the key questions in exoplanet research:**
- Are there habitable planets around other stars?
- What is the architecture of planetary systems?
- How do planets fit in to the process of star formation?
**2. The plan provides the opportunity for early discoveries and risk reduction; spaceborne direct imaging is significantly simplified**
**3. Plan depends on a balance of ground and space; existing and future assets**
**4.** **Plan is flexible to surprises, failures and new discoveries**
**5. Plan is already streamlined in cost but can be stretched out**

- Conclusions