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High‐contrast op/cal imaging with HST Direct detec)on of Jupiter and Kuiper Belt analogs around Fomalhaut Paul Kalas UC Berkeley & SETI Ins)tute “Op/cal images of an exosolar planet 25 light years from Earth” Kalas et al. 2008, Science, 322, 1345 Collaborators: James Graham, Mark Clampin, Mike Fitzgerald, Eugene Chiang, Edwin Kite, Karl Stapelfeldt, John Krist, Mark WyaS, MaS Kenoworthy, John Wisniewski, Ansgar Reiners, Andreas Seifahrt, Stefan Dreizler 1 What do Fomalhaut, Beta Pic and HR 8799 have in common? 2 The A star direct‐detec)on planets Host SpT Dist. (pc) Sep. (AU) Mass (MJ) Age (Myr) Reference Fomalhaut A3V 7.69 119 <3.0 100 ‐ 300 Kalas et al. ‘08 Beta Pic A5V 19.3 8 6 ‐ 12 8 ‐ 20 Lagrange et al. ‘08 HR 8799 A5V 39.4±1.0 68, 38, 24 5‐11 7‐13 30 ‐ 160 Marois et al. ‘08 AB Pic K2 11 ‐ 25 30 – 40 Chauvin et al. ‘05 2M1207 M8 52.4±1.1 54 2 – 25 5 – 12 Chauvin et al. ‘04 GQ Lup K7 140 ± 50 100 4 – 39 <2 Neuhauser et al. ‘05 1RXJ1609 29 G 145±20 330 6 – 12 5 Lefreniere et al. ‘08 CT Cha K7 160±30 440 11 ‐ 23 <2 Schmidt et al. ‘08 47.3±1.8 258 Visible light: Fomalhaut Orbital motion: Fomalhaut, HR 8799, and GQ Lup One epoch only β Pic, 1RXJ1609 What is a planet? Formation matters? Starting early 2011: Gemini Planet Imager And SPHERE 3 Debris disk stars: rela)vely young 107 – 108 yr Plot shows nearby stars with debris disks dust optical depth Adapted from Zuckerman 4 Analogs to the early solar system Strom et al. 2005 t-3 initially, t-1 in the middle flat in recent times note that this for <3 AU 5 Martin et al. 06 Planet Imaging: Easy or Hard? Look at theore)cal apparent magnitude at 0.8 micron Star D (pc) Age (Myr) Star (I band) 1 Jupiter 10 Jupiter Fomalhaut 7.7 200 1.3 mag 26 mag 22 mag Vega 7.8 200 0.0 mag 26 mag 22 mag Beta Pic 19.3 10 3.8 mag 24 mag 19 mag Using Burrows et al. models 6 Fomalhaut 7 Fomalhaut IRAS excess star, but no disk detected in scaSered light Older and less dusty than Pic 1993: Optical observations from Mauna Kea (Paul Kalas) 1999: Hubble observations with WFPC2 (Al Schultz) mv = 1.3 mag 8 HST Advanced Camera for Surveys 2002 STS-109 • High Resolution Channel (HRC) – Optimized for NUV band – 26” x 29” field of view – 0.025”/pixel plate scale – Stellar Coronograph mode 9 Why target Fomalhaut for an HST planet search? • 1984 : IRAS mission finds dust grains orbi)ng Fomalhaut, as well as other stars such as Epsilon Eridani, Vega, and Beta Pictoris • Resolved thermal emission shows a central hole (Holland et al. 1998) • Fomalhaut is nearby (7.7 pc). High proper mo)on (0.4”/yr). • Fomalhaut is a young, main sequence star (200 ± 100 Myr). • Fomalhaut planets are finished with their forma)on, but they are s)ll self‐luminous. 10 2004 Planet Search Using the Advanced Camera for Surveys Kalas, Graham & Clampin “A planetary system as the origin of structure in Fomalhaut’s dust belt” 2005, Nature, Vol. 435, pp. 1067 • No planet found, but dust belt seen for the first time in reflected light • Remarkable properties: Not centered on the star and very sharp inner edge • Explanation: Gravitational Perturbations by a Planet (Wyatt et al. 1999, Moro-Martin & Malhotra 2002) Are the belt’s brightness asymmetries due to planets? orbital period at 140 AU = 1200 yr 11 HST ACS planet search Evidence for a planetary system: Center of symmetry offset Wyatt et al. 1999 G. Schneider, STIS How Observations of circumstellar disk asymmetries can reveal hidden planets:Pericenter glow and its application to the HR 4796A disk Wyatt, M.C. et al. 1999, ApJ, 527, 918 • Particle eccentricity composed of a proper (free) eccentricity, inherent to the particle, and a forced eccentricity due to a perturber. The pericenter also has a free and a forced component. S = stellar position D = center of particle orbit C = center of precession circle P = pericenter of a particle orbit DP = a, semi-major axis of a particle orbit wf = direction of forced pericenter SD = a e SC = a eforced CD = a eproper Torus inner radius = a (1 - eproper) = 133 AU Torus outer radius = a (1+ eproper) • The orbital distribution of particles with common forced elements will be a torus with center, C, offset from the stellar position, S. • The forcing is due to an eccentric companion that could be either inside or outside the belt. HST ACS planet search Key prediction for a planetary system Knife-edge inner boundary means that perturber is inside the belt. Radial cut along 10˚ segment Q2 (apastron), in the illumination corrected image; cut traces the material surface density of the structure rather than its brightness. Blue line is the model fit: 1) Knife-edge inner edge = 133 AU 2) n(r) = n(ro) r -9 3) Scale height = 3.5 AU at 133 AU Key prediction for a planetary system Knife-edge inner boundary means that perturber is inside the belt. Kuiper Belt dust models by Moro-Martin & Malhotra 2002 radial cuts planets 1) Dust produced by KBOs a=35-50 AU, i = 0˚-17˚ 2) 1-40 µm, ρ = 2.7 g cm-3 & 3-120 µm, ρ=1 g cm-3 3) 7 planet, or no planets 4) Solar gravity, RP, P-R drag, solar wind drag. no planets 5) β = RP / gravity ∝ L* / ρ s 2006: HST/ACS deep mul/‐wavelength imaging F435W, F606W, F814W 15 Fomalhaut b 2004 Paul Kalas (University of California, Berkeley) 16 Fomalhaut b 2006 Paul Kalas (University of California, Berkeley) 17 Fomalhaut b 2004 Paul Kalas (University of California, Berkeley) 18 Fomalhaut b 2006 Paul Kalas (University of California, Berkeley) 19 Background star? 20 Speckle Noise? Confirmed in dithered observa)ons, two wavelengths, two types of PSF subtrac)on 21 22 Fomalhaut b: Counterclockwise orbit (below: north up, east left) 24 What is the mass of Fomalhaut b? From the observed proximity of Fom‐b to the belt inner edge (18 AU), and the shape of the radial dust profile: 10 MJ unlikely, <3.0 MJ most probably See Chiang et al. 2009, Astrophysical Journal, 693, 734 Also, Quillen (2006) 25 What is the mass of Fomalhaut b? #1 Fom-b is 18 AU from the inner edge of the belt. Chiang et al. 2009, ApJ, 693, 734 26 What is the mass of Fomalhaut b? From the observed proximity of Fom‐b to the belt inner edge (18 AU), and the shape of the radial dust profile: 10 MJ unlikely, <3.0 MJ most probably See Chiang et al. 2009, Astrophysical Journal, 693, 734 Also, Quillen (2006) 27 What is the mass of Fomalhaut b? #2 From how bright it is in the optical, and non-detection in the infrared…. less than 3 Jupiter masses. Other sources of optical luminosity are possible: glowing hot gas and/or reflected light from a circumplanetary disk Teff = 400 K, M = 1.7 – 3.5 MJ 28 adapted from Marois et al. 08 Fomalhaut b • Fomalhaut b is the lowest luminosity object directly detected outside of our solar system. 29 Fomalhaut b not detected, yet, with Keck & VLT (1.6 – 2.2 µm) and Gemini (3.8 µm) L’ (3.8 microns) Gemini North 8-m NIRI 22”x22” field 1-σ limit 19 µJy Michael Fitzgerald (LLNL) 30 Are we seeing a planet or something else? 31 32 Protogalilean, circumplanetary disk How much flux from star received at Fom-b? Equivalent to flux received by Neptune from Sun. 33 How much flux from Fom-b received at Earth? p = projected geometric surface area of the planet+rings Qs = scattering efficiency (geometric albedo times phase function at given phase) Observations: mv = 25.0 mag Planet only (1.2 RJ, Qs = 0.5): Planet + Rings to Roche Radius Planet + 20 Rp rings (Qs = 0.4) Planet + 35 Rp rings (Qs = 0.1) mv = 30.0 mag mv = 29.5 mag mv = 25.0 mag mv = 25.0 mag For comparison, Callisto at ~27 Jupiter radii 34 Protogalilean, circumplanetary disk Planet with 16 ‐ 35 Rp rings • How does it survive 200 Myr? • Callisto forms in 1 Myr (Mosqueira & Estrada 2003) • Belt crossing orbit? • Planet mass <<3 MJ 35 Summary: Present Day • HST has achieved a defini)ve op)cal detec)on of an exoplanet orbi/ng a main sequence star at 7.7 pc. • Fomalhaut b is between a Neptune and a Jupiter in mass. • Excellent system for detailed study the dynamics between planets and planetesimals. • The unusual brightness of Fomalhaut b at op)cal wavelengths indicates that we may be seeing circumplanetary dust rings reflec)ng light. 36 Major Ques/ons: Fomalhaut, Beta Pic, HR 8799, et al. • Why don’t all young A stars have massive, wide separa)on easily detectable planets? • Inii)al condi)ons or subsequent evolu)on? • Observa)onal bias, only a few young stars near the Sun? • Explain the configura)on and stability of our own solar system? 37 Hot off the press • MMT at 5 µm, no planets >2 MJ between 13 ‐ 40 AU – Kenworthy et al. 2009 • Spitzer / IRAC planet search: No detec)on of planets with mass M > 3.0 MJ – Marengo et al. 2009 • VLT / AMBER op)cal Interferometry resolves stellar photosphere and determines spin Counterclockwise – (Le Bouquin et al. 2009) • Fomalhaut b can form in situ via GI (Nero & Bjorkman 2009) or migra)on that includes a second planet (Crida et al 2009). 38 39 Fomalhaut b 35 Rp rings (Qs = 0.1) (Kalas et al. 2008) Saturn 100 - 200 Rp rings τperp ~ 10-8 (1 km crater) (Verbiscer, Skrutskie & Hamilton 2009) 40 Towards other Earths Enhanced bombardment of planetary satellites Strom et al. 2005 Take away perspective: Direct detec)on of first Earths and their orbits may be due to the detectability of circumplanetary debris rings. 41 Future Work: 3rd & 4th epochs in 2009, 2010 Orbital analysis. Keck, VLT (Reiners), Gemini, WFC3, STIS (no ACS coronagraphy) 42 Future Work: 2011 - 2013 Host Sp T Dist. (pc) Sep. (AU) Mass (MJ) Age (Myr) Reference Fomalhaut A3 V 7.69 119 <3.0 100 ‐ 300 Kalas et al. ‘08 Beta Pic A5 V 19.3 8 6 ‐ 12 8 ‐ 20 Lagrange et al. ‘08 HR 8799 A5 V 39.4±1.0 68, 38, 24 5‐11 7‐13 30 ‐ 160 Marois et al. ‘08 AB Pic K2 47.3±1.8 258 11 ‐ 25 30 – 40 Chauvin et al. ‘05 2M1207 M8 52.4±1.1 54 2 – 25 5 – 12 Chauvin et al. ‘04 GQ Lup K7 140 ± 50 100 4 – 39 <2 Neuhauser et al. ‘05 1RXJ16092 9 G 145±20 330 6 – 12 5 Lefreniere et al. ‘08 CT Cha K7 160±30 440 11 ‐ 23 <2 Schmidt et al. ‘08 Direct Detections Add 100+ rows from GPI and SPHERE results Gemini Planet Imager .berkeley.edu When: Where: Who: How: What: 15 months from today Gemini South PI’s B. Macintosh & J. Graham High-order AO with coronagraphy 0.9 – 2.4 µm, mI < 9 mag stars, polarimetry, R~100 spectroscopy