# Presentation: 227022

## General Astrophysics and the Optical Terrestrial Planet Finder Mission

- Karl Stapelfeldt
- TPF Coronagraph Study Scientist
- NASA / JPL / Caltech

- With thanks to Chas Beichman, Marc Kuchner,
- the TPF Science Working Group,
- and the TPF Coronagraph Design Team

## TPF is ... 

- NASA Origins program’s intended next major space observatory after JWST
- Optimized for high contrast and high spatial resolution
- Designed to
- Directly detect terrestrial planets in the habitable zones                (50-100 mas away) of nearby (distance ~< 20 pc) FGK stars
- Measure their frequency, physical & orbital characteristics
- Spectrally characterize their atmospheres for biomarkers         (O2, H20, CO2, ...)
- Midway through a 4-year program of technology development and preliminary design (“pre-phase A”)
- Led by JPL
- NASA Goddard, Industry, and Universities participating

## New Directions for TPF: NASA HQ Decisions of April 2004

- Now planning for two TPF missions :
- Visible coronagraph with ~3.5x6m telescope aperture, reaching terrestrial planets at 35-50 stars, for flight in 2014.
- Formation-flying infrared interferometer, reaching terrestrial planets at ~150 stars, to follow ~5 years later.
- Combination of optical+IR gives complete picture of planet properties: radii, albedo, atmosphere properties
- Comparative Planetology (imaging of jovian planets, circumstellar disks) promoted to core mission science
- _Explore the general astrophysics capability of the baseline  high-contrast instrument_
- _Consider adding a 2nd instrument for general astrophysics_
-          (more on this shortly)

## Two Complementary TPF Mission Architectures

- “TPF-I”: Infrared nulling interferometer operating at 10 μm
- Contrast requirement 107 : 1
- Four or more formation-flying spacecraft with 3 meter class cryogenic telescopes, ~100m apart
- 50% European participation (Darwin)

- “TPF-C”: Coronagraphic telescope operating at 0.5 μm
- Contrast requirement 1010 : 1
- Precision wavefront control using deformable mirrors to correct quasi-static wavefront errors
- Requires high degree of thermal & mechanical stability
- ~10% European participation

## Laboratory Coronagraph Now Suppressing Starlight by 500,000,000:1

- Narrowband laser illumination
- Average contrast = 2x10-9
-      at 4th Airy ring, 800 nm
- Minimum contrast = 3 x10-10
- TPF contrast requirement ≤10-10

- High Contrast Imaging Testbed Facility

- High Actuator Density Deformable Mirrors

- 1024 Actuators	4096 Actuators

## TPF Coronagraph Conceptual Design

- Deployed secondary tower

- V-groove deployment boom

- Spacecraft equipment support panel

- Deployed HGA

- Primary mirror thermal enclosure (coronagraph sensor and spectrograph inside)

- Deployed solar array

- Primary mirror
- (6m x 3.5m)

- Cross section of deployed V-groove layers

- Good capability to study stars out to ~15  pc (depending on spectral type)
- Produces real images of planetary systems
- Good biomarkers
- Monolithic off-axis elliptical primary mirror with deployable secondary
- Thermal shield provides highly stable environment for telescope

*Solar system analog at 10 pc*

## TPF Coronagraph Stowed in Launch Shroud

- Clamshell support cylinder separates after launch and releases spacecraft

- Bipods support flight system to cylinder

- 5.08m (OD)

- 4.57m (ID)

- 19.814m

_**Stowed Configuration in Delta IV-H**_

## Main instrument for TPF-C:

- 3.5 x 6 m telescope delivers PSF with FWHM 29 mas x 17 mas at V
- Spectropolarimetric coronagraphic imaging camera
- 0.35 <  λ < 1.05 μm w/CCDs, Ag coated optics
- High contrast FOV of 2-3” at V band; overall FOV perhaps 30”
- Integral field spectrograph, R~70-150 (planets & speckles)
- Simultaneous imaging in two orthogonal polarizations
- Observing strategy for planetology:
- Day or two integration times for each star at each epoch (detection)
- Repeat visits at 5 or more epochs over 2 year detection survey
- (Completeness, proper motion tests)
- Mulitiple roll angles, up to +/- 90 degrees, to aid in separation speckles from planets
- Weeks of additional observations for spectroscopy, orbit tracking of detected planets
- Quite similar to the observing strategy for HST/GOODs

## Guidelines for Additional Astrophysics Programs

- TPF should be capable of carrying out a meaningful program of general astrophysics relevant to Origins,  SEU & SSE goals.  BUT
- Do not compromise planet-finding (at all!)
- Minimize the impact on mission cost
- Apply coronagraph to relevant astrophysical problems
- A second instrument should be simple, affordable
- Do not take up too much observing time (<25%)
- Parallel deep field observations would fit in very well

## Applications for the coronagraph instrumentoutside planetology

- Post main-sequence circumstellar structure:     history of mass loss

- Quasar hosts & their evolution

- ACS image of 3c273

- HST image of the Red Rectangle

## Illustrative  Extension to  TPF-C For General Astrophysics

- “Wider Field” Camera, e.g. 2-5’ FOV, multiple filters
- Consider a program of parallel science during planet finding observations :
- 50 target stars (50% of 5 yr mission)             yield 18 days of integration per field
- With 6 x HST collecting area 		> UDF sensitivity on 25 |b|> 30o fields
- 200 comparative planetology targets (25% of mission time) with 3 days of integration:	 ~ HDF sensitivity on 100 |b|> 30o fields
- Multiple visits per target: variability studies
- Shallower targeted observations to complement JWST near-IR and mid-IR surveys
- Combination of JWST and TPF-C is equivalent to Spitzer and HST, but with greater collecting area and better angular resolution

## Issues for a TPF-C wider field camera

- Requires new approach for telescope pointing
- Current design uses single bright guidestar
- What is the right FOV and pixel scale for cosmological surveys?
- JDEM-like FOVs likely to be difficult;
- very deep fields with modest FOV more likely
- Optical channel only, or near-IR as well ?
- How far off-axis does the camera need to be ?
- 		(to push scattered light to zodiacal background levels)
- How well can other facilities obtain comparative deep fields near bright stars (V= 2 to 6) ?
- Can any ultraviolet performance be provided ?

## Stars in Nearby Galaxies

- TPF-C

- HST

- TPF-C extends ability to resolve/detect individual stars in other galaxies
- Potential scientific return includes star formation histories for much wider range of Hubble Type & luminosity (Tom Brown, STScI)
- Cepheids in the Coma	cluster

## Dark Energy & Dark Matter with TPF-C

- TPF-C and  HST SN Searches
- HST study (Riess et al. 2004)
- 5 epochs  at intervals of 45 days (0.1 square degrees) in Z band (2000 s exposures) to 26 mag
- TPF-C Parallel field study
- 5 x area (25 5’ x5’ fields)
- 3-5 yr baseline
- Out to 1.7  micron, SNIa to z~3 (SNII to higher z)
- ~100 x HST Supernova sample
- Repeat SN Ia experiment with Type II plateau SNs to z ~ 4
- Strong Lensing: Detailed Arc Studies
- Detect many more arcs
- Resolve substructure in arcs
- Constrain lens models
- Use features in arcs to constrain lumpiness in cluster halos

*Riess et al. 2004*

## Simulated HST/TPF-C image of z=1 galaxy lensed by cluster at z=0.35 yields ~10x as many constraints on cluster dark matter distribution as HST/ACS images --- Simon Dedeo, Ed Turner

## Hi-z Galaxy Morphology

- When and how do galaxies form?
- Star formation history, galaxies shapes, relation to black hole formation
- 8-10 m telescopes have found ~103 galaxies with 3<z<6 but little morphological data
- TPF-C: morphologies of “young” stellar component
- 20 mas spatial resolution
- Observed 0.7 m image   rest frame  UV @ z=4
- Complement JWST with  2-3 better resolution than HST

*2MASS:*
*TPF-I Z=4*

*DSS: *
*TPF-I z=4*

*Galex:*
*TPF-C z=4*

*JWST*

*TPF-C*

*Galaxy Size*

## Developing a General Astrophysics Capability for TPF-C

- April 14-15 Princeton meeting began to explore the science case
- Review of two-TPF strategy by CAA this week
- Prepare TPF-SWG white paper over summer/fall 2004 for presentation at winter AAS (San Diego)
- NASA HQ to establish requirements for general astrophysics, including budget guidelines.
*Your input to the project *

## TPF Science Working Group

- Dana Backman	 	*Ames*
- Robert Brown 		*STScI*
- Christopher Burrows	*Consultant*
- William Danchi  		*GSFC*
- Malcolm Fridlund	*ESTEC*
- Eric Gaidos          	*Hawaii*
- Philip Hinz            	*Arizona*
- Kenneth Johnston 	*USNO*
- Marc Kuchner          	*Princeton** *
- Doug Lin 		*UCSC*
- René Liseau 		*Stockholm*
- Jonathan Lunine  	*Arizona*
- Victoria Meadows 	*SSC/JPL*

- Gary Melnick		*CfA*
- Bertrand Mennesson	*JPL*
- David Miller 		*MIT*
- Charley Noecker 	*Ball Aero*
- Huub Röttgering 	*Leiden*
- Sara Seager		*DTM*
- Eugene Serabyn 	*JPL*
- William Sparks 		*STScI*
- Wesley Traub		*CfA*
- John Trauger   		*JPL*
- Ted von Hippel 		*Texas*
- Neville Woolf 		*Arizona*

- Charles Beichman (Chair)       project scientist   JPL/Caltech
- Zlatan Tsvetanov                     program scientist  NASA HQ

- Names in green = coronagraph subcommittee members

## Two sides of the coin for TPF-C :

- GENERAL ASTROPHYSICS

- Planet finding

- Observing time

- Imaging field of view ?

## Backup Slides

## High Contrast Imaging Testbed (HCIT)

- Corrected “Star” Image

- Apodized Occulting Mask

- High Contrast Coronagraphic Field

- Illumination at Pupil Plane

- Apodized Pupil Mask

- Wavefront Phase
- Correction

## Earthshine Reveals Visible Spectrum

*Woolf, Traub and Jucks 2001*

-  Oxygen A-band and water are excellent bio-markers
-  CO2 at 1 m drives long wavelength performance
- Resolution of 75 is adequate
-  Look for surface features, e.g. chlorophyll

## The Case for 2 TPF’s: Visible and IR

- Astrobiologists and TPF-SWG strongly endorse a TPF program that ultimately observes planets in BOTH mid-IR and near-IR/visible spectral ranges
*“**Both the mid-infrared and the visible to near infrared spectral ranges offer valuable information regarding biomarkers and planetary properties, therefore both ranges merit serious scientific consideration for TPF.  The best overall strategy for the Origins program includes a diversity of approaches, therefore both wavelength ranges ultimately should be examined prior to launching the ‘Life-Finder’ mission.”  (Des Marais et al 2002).*
- Observations at two wavelength regions greatly improve knowledge and understanding in many areas of astrophysics
- Imagine cosmology without coverage at *both* visible (stars and galaxies) and IR (ultra-luminous galaxies, high-redshift universe, or CMB) wavelengths
- Together, TPF-C and TPF-I provide multi-wavelength, high angular resolution observations of planets, planetary systems, general astrophysical targets

## Achieving the Promise of TPF

- NASA and the TPF project have  responded to Decadal direction by undertaking project studies and a technology program built around four scientific goals
- Search for Earth-like planets
- Characterize planets, their  atmospheres, and search for signatures of life
- Carry out a program of comparative planetology
- Enable a program of “revolutionary” astrophysics
- The TPF technology program has proven highly successful so that a combination of visible & mid IR facilities now promises to provide complete physical characterization of planets and planetary systems, a robust detection of the signatures of life, and unique capabilities for general astrophysics
- TPF-Coronagraph for visible light observations for initial sample of 35~50 stars
- TPF-Interferometer for mid-IR observations for broader sample of 150-200 stars, for complementary and/or confirming data for planet characterization and biomarkers

## Discovery Space for Basic TPF-C

*Ben Lane and Sally Heap*

## Priorities for  TPF Science

**Design TPF mission around ability to detect and characterize habitable planets and to search for signs of life**
**Ensure capabilities exist to study all constituents of planetary systems **
**Use existing capabilities to carry out program of general astrophysics**
**Enhance capabilities to carry out more extensive program of general astrophysics**

## Evolution of AGN Tori

- Do tori exist?  Or are they dust clouds or spiral arms?
- Can we unify the AGN zoo (Seyferts, Quasars, BLACs etc)?
- Weak AGN to z~1, strong AGN to z~10
- TPF-C polarization capability at high angular resolution (20 mas)  to study emission and scattering  processes

## Imaging Host And Lens Galaxies Of Gravitationally Lensed Quasars

- Host galaxy
- of a bright &
- low redshift
- quasar.  ---->
- Change with
- redshift?

- <---- Optical Einstein
- Ring gravitational lens.

- Reconstructed ***0.01”***
***resolution*** image of a
- high z star-formation
- burst galaxy.     ---->

- The details of resolved,  low surface brightness  objects constrain lens models