Debris Disk Science with GMT Inseok Song, University of Georgia for “Opening New Frontiers with the Giant Magellan Telescope” in Oct 2010 Zodiacal light: APOD: 2010 Sep 13, Taken in Namibia after a sunset in June.

Why Debris Disks? NRC Astro2010 Report NRC Astro2010 Report Telescopes on the ground and in space have even directly imaged as distinct point sources a few large planets. … we can learn about planetary systems by measuring infrared and radio emission from giant disks of gas out of which planets can form. … Terrestrial planets are relatively small and dim, and are easily lost in the exozodiacal light that is scattered by the dusty disks that typically orbit stars. The observational challenge is great, but armed with new technologies and advances in understanding of the architectures of nearby planetary systems …

Debris Disks and Planets Debris disks act as indirect evidence of exo-planetary systems. But, at the same time, they are obstacles in direct imaging of Earth-like planets. Debris disks act as indirect evidence of exo-planetary systems. But, at the same time, they are obstacles in direct imaging of Earth-like planets. Need to understand the architecture of debris disks Need to understand the architecture of debris disks

Breaking the degeneracy of SEDs Debris disk studies are based on Spectral Energy Distribution (SED). same SED with different grain configurations same SED with different grain configurations large grains at r small small grains at r large grain population over r Need a spatially resolved image of DD

Scattered imaging + thermal imaging M planet =5M E, a p =10AU, β=0.023 M planet =5M E, a p =10AU, β=0.023 Poynting-Robertson effect caused a grain sorting based on particle size Poynting-Robertson effect caused a grain sorting based on particle size  different appearance at different wavelengths. (Stark et al. 2009) density scattered light 10μm image

Need to spatially resolve Debris Disks 17 resolved debris disks in scattered light to date (optical and near-IR) 17 resolved debris disks in scattered light to date (optical and near-IR)

Need to spatially resolve Debris Disks But only four debris disks imaged in thermal IR But only four debris disks imaged in thermal IR To increase the number of spatially resolved debris disks We need 1. Good targets 2. Larger telescope with a better IR imager

Some important facts Adaptive secondary mirror: Adaptive secondary mirror: o excellent for thermal IR observations  only two warm optics (M1 + M2) o AO corrected mid-IR observations (Strehl ratio > 98%) Extreme AO : Strehl > 99% Extreme AO : Strehl > 99% mid-IR imager (MIISE or TIGER): 5-25mu, 5-25mu, R=5-5000, R=5-5000, FOV=30” FOV=30” FWHM = 40mas at 5mu, FWHM = 40mas at 5mu, Sun-Earth at 25pc away… 1AU  40mas

Can GMT/TIGER really resolve most Debris Disks? MMT Adaptive Secondary result as a test case. MMT Adaptive Secondary result as a test case. Expected Strehl ratio at mid-IR > 98% Expected Strehl ratio at mid-IR > 98%

Expected performance of TIGER MMT Adaptive Secondary result as a test case. MMT Adaptive Secondary result as a test case. Expected Strehl ratio at mid-IR > 98% Expected Strehl ratio at mid-IR > 98% can do suppression Credit: Phil Hinz (Steward Observatory)

What we can do with resolved debris disks : case I Constrain the location of exo-asteroidal belt around ζ Leporis. Constrain the location of exo-asteroidal belt around ζ Leporis. (Moerchen et al ) (Moerchen et al ) Azimuthally averaged radial plots of ζ Leporis (red) and a nearby point- spread-function (PSF) star (black).

AU Mic disk observed at four bands (Fitzgerald et al. 2007) AU Mic disk observed at four bands (Fitzgerald et al. 2007) What we can do with resolved debris disks : case II

Spatially resolved mid-IR spectroscopy of β Pic (e.g., Weinberger+ 2003) Spatially resolved mid-IR spectroscopy of β Pic (e.g., Weinberger+ 2003) What we can do with resolved debris disks : case III

Kuiper Belt Disks Other thermal IR instruments competing w GMT/TIGER Surface brightness high enough? Surface brightness high enough? Enough targets for statistically meaningful studies? Enough targets for statistically meaningful studies?

JWST sensitivity GMT sensitivity Known Population of Debris Disks from IRAS currently known debris disk from IRAS (Rhee et al. 2006)

Known Population of Debris Disks from IRAS currently known debris disk from IRAS (Rhee et al. 2006) HIP 7345, 20 Myr old Simulated 1hr 18μm image

GMT/TIGER will image planets also… Higher exoplanet flux at M and N bands especially for lower mass planets Higher exoplanet flux at M and N bands especially for lower mass planets Typical ages of debris disk stars are < 500 Myr (young, bright planets) Typical ages of debris disk stars are < 500 Myr (young, bright planets) GMT M-band (5σ, 1hr) limit : 5.14 μJy 200 Myr 10M J planet or 50 Myr 5M J are about 0.8mJy at M-band detectable in 5min exposure with GMT/TIGER! YJHKLN 700 K planet 400 K planet M

We will image disk together with planets! GMT/TIGER can detect a 1 M J planet at various ages. GMT/TIGER can detect a 1 M J planet at various ages. Expect an image like this!! Expect an image like this!! Composite image of β Pictoris disk:10μm, planet:3.6μm

More targets to come! Increasing the population of Debris Disks IRAS fully used IRAS fully used Spitzer being summ. Spitzer being summ. AKARI wasn’t useful AKARI wasn’t useful  WISE (about 10 8 sources) SPICA (not all-sky) SPICA (not all-sky) WISE sky coverage as of 2010 Sep

Anticipated Results GMT should be able to obtain spatially resolved images of several dozen Debris Disks (both in scattered and thermal light) GMT should be able to obtain spatially resolved images of several dozen Debris Disks (both in scattered and thermal light) Some (or many or most) with embedded planets imaged (both in nearIR and thermal) Some (or many or most) with embedded planets imaged (both in nearIR and thermal) 200 Myr with a 5M J planet and L IR /L bol =4x10 -4, T dust =300K GMT/TIGER 1hr at M-band

Work To Do: Debris Disk Database

Rocky planets with GMT? planets warmed by the star rather than self- luminous gas giant planets. planets warmed by the star rather than self- luminous gas giant planets. DesMarais et al. 2002

Known Population of DDs Show distro of tau versus theta Show distro of tau versus theta

All imaged exoplanets so far… all with disks!! Despite several major exoplanet imaging programs targeted hundreds of nearby stars where only ~20% of them are debris disk stars, most successfully imaged exoplanets are around stars with debris disks: HR8799, beta Pic, and Fomalhaut.

Scattered imaging + thermal imaging M planet =1M E, a p =1AU, β=0.023 M planet =1M E, a p =1AU, β=0.023 Poynting-Robertson effect caused a grain sorting based on particle size Poynting-Robertson effect caused a grain sorting based on particle size  different appearance at different wavelengths. (Stark et al. 2009) density scattered light 10μm image

Scattered imaging + thermal imaging M planet =1M E, a p =1AU, β= M planet =1M E, a p =1AU, β= Poynting-Robertson effect caused a grain sorting based on particle size Poynting-Robertson effect caused a grain sorting based on particle size  different appearance at different wavelengths. (Stark et al. 2009) density scattered light 10μm image

Giant Magellan Telescope 7 x 8m segmented mirrors 7 x 8m segmented mirrors to be on Las Campanas in Chile to be on Las Campanas in Chile First light 2019 First light 2019 Carnegie + Harvard/SAO + Arizona + Chicago + Australias + Korea + … Carnegie + Harvard/SAO + Arizona + Chicago + Australias + Korea + … Other similar telescopes  all on-line around 2020 TMT (30m, in Hawaii) E-ELT (42m, in Chile) JWST (6.5m, in space) LSST (8m, surveying)