Observing the birth of planets Valentin Christiaens Postdoctoral researcher - Monash University University of Melbourne - 17 October 2018
Outline ❖ I. Introduction ❖ High-contrast imaging of exoplanets ❖ Transition disks ❖ II. Direct search for protoplanets ❖ In thermal-IR ❖ In NIR with an IFS ❖ III. Indirect constraints: spiral arms and hydro-dynamical simulations ❖ IV. Future of the search for protoplanets ❖ V. Conclusions
Outline ❖ I. Introduction ❖ High-contrast imaging of exoplanets ❖ Transition disks ❖ II. Direct search for protoplanets ❖ In thermal-IR ❖ In NIR with an IFS ❖ III. Indirect constraints: spiral arms and hydro-dynamical simulations ❖ IV. Future of the search for protoplanets ❖ V. Conclusions
I. Introduction Challenge of high-contrast imaging “Where’s the firefly?” Credit: G. Duchêne
I. Introduction Challenge of high-contrast imaging Credit: G. Duchêne
I. Introduction Challenge of high-contrast imaging Credit: G. Duchêne
I. Introduction Challenge of high-contrast imaging 2 major hurdles to directly image exoplanets: contrast and angular resolution ❖ (Mawet+05,Absil+16) HCI techniques: 1) adaptive optics 2) coronagraphy 3) differential imaging ❖ no AO AO AO + coronagraph AO + coronagraph Stellar halo subtracted Frames combined … … … 0.5’’ 0.5’’ 0.5’’ 0.5’’ Residual hurdle: (quasi-static) speckles ❖
I. Introduction PSF modeling + differential imaging Reference star Differential Imaging (RDI) Spectral Differential Imaging (SDI) - Credit: B. Macintosh Angular Differential Imaging (ADI) = Credit: C. Marois Credit: O. Absil
I. Introduction Principal component analysis (PCA) Build an orthogonal basis to reproduce the observed PSFs ❖ PSFs Analogy: obs PSF #1 obs PSF #N ❖ … Male face model built from a basis of female faces obs-model model PSF (100 pcs)
I. Introduction Principal component analysis (PCA) + ADI Credit: C. Gomez
I. Introduction Exoplanet direct images 10m-class telescopes 2003 2009 2008 VLT (Chile) 2004 2013 Uranus Gemini South (Chile) orbit 2015 2013 Subaru (Hawaii) Keck (Hawaii)
I. Introduction Exoplanet direct images Directly Imaged 2003 2009 2008 2004 2013 Uranus Mordasini+18 orbit 2015 2013 Directly imaged exoplanets provide invaluable information: ❖ parameter space inaccessible with other techniques Niche: young giant planets (on wide orbit) ❖ } spectrum => T eff , log(g), atmosphere composition ❖ => constraints on planet formation models exact orbital architecture of exoplanetary systems ❖
I. Introduction Formation of giant planets Core accretion Gravitational instability
I. Introduction Gravitational instability If AND ❖ GI condition (Toomre 1964) Cooling condition (Gammie 2001) => gravitational fragmentation Forgan & Rice 2013 Rice+2003
I. Introduction Core accretion Observable Obs. Credit: C. Dullemond 5 main steps: 1) Grain growth ❖ 2) Planetesimal formation? 3) Core formation 4) Hydrostatic growth 5) Runaway accretion
I. Introduction Circumplanetary disk (CPD)? Expected SED CPD at the scale of the protoplanetary disk ❖ ❖ Credit: SNSC Eisner 2015 solid: protoplanet alone dashed: protoplanet + CPD Perez+2015
I. Introduction Where to look for protoplanets? Protoplanetary disk Molecular cloud (up to a few Myr old) Transition disk Debris disk (~1-10 Myr old) (> 10 Myr old)
I. Introduction Possible companion signposts in TDs NIR polarized light Sub-mm continuum Large cavities+asymmetries Spiral arms a) b) (small grains) (large grains) Sub-mm lines (gas) Credit: N. van der Marel Shadows / Inner Warps Several mechanisms can induce these disk features… NIR polarized light but a single one might be enough: the dynamical (small grains) interaction with embedded companion(s)
II. Direct search for protoplanets in TDs - in thermal IR Protoplanet candidates? ? => First bona fide detection required (as of 6 months ago)
Outline ❖ I. Introduction ❖ High-contrast imaging of exoplanets ❖ Transition disks ❖ II. Direct search for protoplanets ❖ In thermal-IR ❖ In NIR with an IFS ❖ III. Indirect constraints: spiral arms and hydro-dynamical simulations ❖ IV. Future of the search for protoplanets ❖ V. Conclusions
II. Direct search for protoplanets in TDs - in thermal IR Protoplanet candidate MWC 758 b (Reggiani, Christiaens+ 2018) Previous observations Keck/NIRC2 (L’-3.8µm) - PCA-ADI IR polar light Oct. 2015 Oct. 2016 Marino+15 Benisty+15 r~0.12’’ (~18au) r~0.12’’ (~18au) sub-mm radio BRIGHT! Protoplanet with CPD: 4 M Jup accreting at 10 -5 M Jup yr -1 ? (based on models in Zhu 2015) ❖
II. Direct search for protoplanets in TDs - in NIR Integral field spectroscopy Angular Differential Imaging (ADI) Credit: C. Marois Spectral Differential Imaging (SDI) Credit: B. Macintosh
II. Direct search for protoplanets in TDs - in NIR Mini-survey of transition disks with VLT/SINFONI (Christiaens+ in prep.) VLT/SINFONI , H + K band (2000 channels in 1.45–2.45 µm) ❖ Targets: 5 transition disks with large gaps and signposts of companion presence ❖ Post-processing using PCA-ADI, -SDI, -ASDI and -ADBI ❖ => At 0.15’’–0.20’’ separation, similar contrast as newer instruments (e.g. VLT/SPHERE )
II. Direct search for protoplanets in TDs - in NIR Results of the VLT/SINFONI survey: PDS 70 (Christiaens+ 2018b, subm. to MNRAS) Disk Companion candidate or gap-crossing bridge? Polarized light - 1.66 µm Polarized light - 1.2 µm 0.1’’ 0.1’’ 20au 20au Hashimoto+2012 Keppler+2018 Continuum 0.1’’ 0.88 mm 20au (Christiaens+ 2018b, Long+2018 subm. to MNRAS)
II. Direct search for protoplanets in TDs - in NIR PDS 70 b? (Keppler+ 2018; Müller+2018) Disk Protoplanet? Polarized light - 1.66 µm Polarized light - 1.2 µm PCA-ADI - 2.2 µm m-ADI - 2.2 µm 0.1’’ 0.1’’ 0.1’’ 0.1’’ 20au 20au 20au 20au Hashimoto+2012 Keppler+2018 Keppler+2018 Müller+2018 Continuum 0.1’’ 0.88 mm 20au => 0.2-55 M Jup Müller+2018 Long+2018
II. Direct search for protoplanets in TDs - in NIR Results of the VLT/SINFONI survey: HD 142527 (Christiaens+ 2018a) PCA-ADI: detection in ~2000 First extraction of the medium resolution spectrum of a companion ❖ ❖ individual spectral channels, e.g.: at < 0.1’’ => Confirmation of first detections in Biller+2012 and Close+2014
II. Direct search for protoplanets in TDs - in NIR Results of the VLT/SINFONI survey: HD 142527 (Christiaens+ 2018a) Spectral characterization of the companion Comparison to a template library ❖ ❖ Best-fit template spectrum from SpeX library ❖ => M2.5 => M2.5 1.0
II. Direct search for protoplanets in TDs - in NIR Results of the VLT/SINFONI survey: HD 142527 (Christiaens+ 2018a) Mass and age estimates based on ❖ evolutionary tracks in HR diagrams Spectral characterization of the companion ❖ a) Temperature and surface gravity estimated using BT-SETTL 0.6 ❖ 0.5 0.5 2 0.4 synthetic spectra: 0.3 1 3 2 0.2 H absolute magnitude 3 4 5 4 8 10 Best-fit model including a hot Best-fit photospheric model 0.1 5 circum-secondary environment 6 Evolutionary tracks for di ff erent masses (in M � ) Isochrones (in Myr) Best fit BT-SETTL model alone Best fit BT-SETTL+environment model 7 4000 3900 3800 3700 3600 3500 3400 3300 3200 3100 3000 2900 T e ff (K) It’s a small star... not a planet! b) 0.6 0.5 0.5 0.4 2 0.3 1 2 0.2 3 K absolute magnitude 3 4 5 8 4 10 0.1 5 6 Evolutionary tracks for di ff erent masses (in M � ) Isochrones (in Myr) => T=3500 100K (T envt ~ 1700K) Best fit BT-SETTL model alone Best fit BT-SETTL+environment model 7 4000 3900 3800 3700 3600 3500 3400 3300 3200 3100 3000 2900 T e ff (K) => M~0.35 0.05 M Sun ; Age~1–3 Myr
Outline ❖ I. Introduction ❖ High-contrast imaging of exoplanets ❖ Transition disks ❖ II. Direct search for protoplanets ❖ In thermal-IR ❖ In NIR with an IFS ❖ III. Indirect constraints: spiral arms and hydro-dynamical simulations ❖ IV. Future of the search for protoplanets ❖ V. Conclusions
III. Characterization of spiral arms in TDs Spiral arms in TDs Companion-induced ❖ density waves? (Lin & Papaloizou 79, Rafikov 02) Gravitational instability? ❖ (Durisen+07, Tomida+17) Stellar flyby? ❖ (Pfalzner+03, Quillen+05) Shadow-induced spirals? ❖ (Montesinos+16,+18)
III. Characterization of spiral arms IR spiral arms of HD 142527 (Price+18) (Biller+12) (Close+14) (Christiaens+18a) Multi-epoch astrometry of the companion (Lacour+16) Observations: spirals and shadows Hydro-dynamical simulations for different orbits of the companion (Fukagawa+06, Avenhaus+13)
III. Characterization of spiral arms HD 142527: a resolved case (Price+18) O a) b) c) d) e) f) S g) h) i) j) k) l) All features of the disk can be qualitatively interpreted as disk-binary interaction: ❖ mm- and cm-size grains crescent-shape distribution ❖ CO distribution ❖ possible gap-crossing filaments ❖
Recommend
More recommend
