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Disks in Nearby Planetary Systems with JWST and ALMA Meredith A. MacGregor NSF Postdoctoral Fellow Carnegie Department of Terrestrial Magnetism 233rd AAS Meeting ExoPAG 19 January 6, 2019 MacGregor Circumstellar Disk Evolution molecular cloud 0 Myr main sequence star + planets (?) + debris disk (?) Star Formation > 10 Myr pre-main sequence star + protoplanetary disk Planet Formation 1-10 Myr MacGregor Debris Disks: Observables First extrasolar debris disk detected as “excess” infrared emission by IRAS (Aumann et al. 1984) SPHERE/VLT Herschel ALMA VLA Boccaletti et al (2015), Matthews et al. (2015), MacGregor et al. (2013), MacGregor et al. (2016a) Now, resolved at wavelengthsfrom from Herschel optical DUNES (scattered light) to millimeter and radio (thermal emission) MacGregor Planet-Disk Interactions Planets orbiting a star can gravitationally perturb an outer debris disk Expect to see a variety of structures: warps, clumps, eccentricities, central offsets, sharp edges, etc. Goal: Probe for wide separation planets using debris disk structure HD 15115 β Pictoris Kuiper Belt Asymmetry Warp Resonance Kalas et al. (2007) Lagrange et al. (2010) Jewitt et al. (2009) MacGregor Debris Disks Before ALMA Epsilon Eridani HD 95086 Tau Ceti Beta PictorisHR 4796A HD 107146 AU Mic Greaves+ (2014) Su+ (2015) Lawler+ (2014) Vandenbussche+ (2010) Koerner+ (1998) Hughes+ (2011) Matthews+ (2015) 49 Ceti HD 181327 HD 21997 Fomalhaut HD 10647 (q1 Eri) Eta Corvi HR 8799 Roberge+ (2013) Lebreton+ (2012) Moor+ (2015) Acke+ (2012) Liseau+ (2010) Lebreton+ (2016) Matthews+ (2014) HD 115617 (61 Vir) HD 139664 HD 207129 HD 38858 HD 15115 HD 61005 HD 32297 Wyatt+ (2012) Herschel DEBRIS Lohne+ (2012) Kennedy+ (2015) MacGregor+ (2015a) Ricarte+ (2013) Maness+ (2008) Steele+ (2016) MacGregor And Now With ALMA… Epsilon Eridani HD 95086 Tau Ceti Beta PictorisHR 4796A HD 107146 AU Mic MacGregor+ (in Su, MacGregor+ (2017) MacGregor+ (2016) Dent+ (2014) Kennedy+ (2018) Ricci+ (2015) MacGregor+ (2013) prep.) Marino+ (2018) 49 Ceti HD 181327 HD 21997 Fomalhaut HD 10647 (q1 Eri) Eta Corvi HR 8799 Booth+ (2016) Lieman-Sifry+ (2015) MacGregor+, Wyatt+ Marino+ (2016) Marino+ (2016) Moor+ (2013) MacGregor+ (2017b) Wilner, Hughes+ (2017) (in prep.) MacGregor+ (in MacGregor+ (2018) prep.) HD 115617 (61 Vir) HD 139664 HD 207129 HD 38858 HD 15115 HD 61005 HD 32297 Marino+ (2017) MacGregor+ (in MacGregor+ (in MacGregor+ (in MacGregor+ (in prep.) MacGregor+ (2018) MacGregor+ (in MacGregor+ (2018) prep.) prep.) prep.) prep.) MacGregor The Fomalhaut System First image from Hubble showed A-type star — 7.7 pc — 440 Myr narrow belt with possible planet (Kalas et al. 2005, 2008, 2013) Half of the disk imaged by ALMA in Cycle 0 (Boley et al. 2012) Follow-up ALMA image in Cycle 2 (White et al. 2016) ALMA Cycle 3 project to complete a 7-pointing mosaic map (PI Paul Kalas, MacGregor et al. 2017, Matrà et al. 2017) MacGregorWhiteBoleyKalas et et al. al. (2017b) (2016)(2012)(2013) MacGregor Modeling Disk Structure Fbelt [mJy] = 24.7 ± 0.1 Fstar [mJy] = 0.75 ± 0.2 Rbelt [AU] = 136.3 ± 0.9 Δa [AU] = 13.5 ± 1.6 MacGregor et al. (2017b) incl [°] = 65.6 ± 0.3 PA [°] = 337.9 ± 0.3 New approach for modeling eccentric rings: ef = 0.12 ± 0.01 1. Compute true anomaly and orbital positions for ~104 particles ep = 0.06 ± 0.04 2. Create 2D histogram of particle positions binned at pixel resolution ω [°] = 22.5 ± 4.3 3. Assume r-0.5 temperature profile and compute flux in each pixel f 4. Account for disk geometry (inclination, position angles), offsets, etc. Incorporate into MCMC framework previously MacGregor Probing Planet-Disk Interactions If a disk is shaped by a planet, theory predicts azimuthal variations in the disk width, with the largest difference between apocenter and pericenter Expected width difference for Fomalhaut is resolvable with ALMA (~4 AU) New observations will . (1) determine whether the disk is shaped through secular perturbations by a planet (2) identify any additional small-scale substructure in the disk MacGregor The HR 8799 System A-type star — 39.4 pc — 30 Myr System consists of: 1. Four 5—10 MJup directly-imaged companions with projected separations of 14, 24, 38, and 68 AU (Marois et al. 2008, 2010; Marley et al. 2012) 2. A warm inner belt (T ~ 150 K) 3. A cold outer belt (T ~ 35 K) 4. Extended halo of small grains out to ~1000 AU Wilner, MacGregor, et al. (2018) MacGregor The Mass of Planet b Translate constraint on disk inner edge into constraint on mass of planet b (Pearce & Wyatt 2014): Adopting: Yields: Wilner, MacGregor, et al. (2018) Current mass estimates derived from evolutionary models Need for an independent constraint! MacGregor ALMA and JWST ALMA can… 1. Resolve structure in cold Kuiper Belt analogues 2. Detect molecular gas lines (e.g., CO isotopologues) planetesimal(belts( terrestrial(planets( giant(planets( disk(halo( ~1500(K( ~300(K( ~150(K( ~50(K( Increasing…+ Terrestrial( Asteroidal( Kuiper(Belt( distance( Zone( Zone( Zone( wavelength( Decreasing…+ ~10$μm$ ~24$μm$ >60$μm$ temperature( JWST$ ALMA$ JWST can… 1. Resolve structure in debris disks with multiple components 2. Probe grain composition (silicate features) and atomic gas lines (e.g., H2O) MacGregor The Eta Corvi System Hot (300 K) asteroidal Spitzer IRS spectrum shows water- and dust at a few AU carbon-rich 10 μm silicate emission feature Spitzer ALMA Marino et al. (2016); Lisse et al. (2012) MacGregor Take-Aways (1) ALMA has revolutionized our understanding of debris disks at millimeter wavelengths by increasing both resolution and sensitivity. (2) JWST will provide complementary information on warm debris disks, as well as grain composition and disk gas content. (3) We can robustly model and characterize the millimeter emission of nearby debris disks (e.g., Fomalhaut, HR 8799). (4) In nearby systems, we are beginning to make connections between debris disk structure and underlying planetary systems. MacGregor The ALMA Array Main Array 50 x 12-m antennas Atacama Compact Array (ACA) 12 x 7-m antennas All observations shown here taken at 1.3 mm (230 GHz, Band 6) with 8 GHz of bandwidth and two linear polarizations (XX, YY).
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