Astrophysics - Earth and Planetary Astrophysics; Astrophysics - Solar; and Stellar Astrophysics
Abstract :
[en] Terrestrial and sub-Neptune planets are expected to form in the inner (less than 10 AU) regions of protoplanetary disks1. Water plays a key role in their formation2-4, although it is yet unclear whether water molecules are formed in situ or transported from the outer disk5,6. So far Spitzer Space Telescope observations have only provided water luminosity upper limits for dust-depleted inner disks7, similar to PDS 70, the first system with direct confirmation of protoplanet presence8,9. Here we report JWST observations of PDS 70, a benchmark target to search for water in a disk hosting a large (approximately 54 AU) planet-carved gap separating an inner and outer disk10,11. Our findings show water in the inner disk of PDS 70. This implies that potential terrestrial planets forming therein have access to a water reservoir. The column densities of water vapour suggest in-situ formation via a reaction sequence involving O, H2 and/or OH, and survival through water self-shielding5. This is also supported by the presence of CO2 emission, another molecule sensitive to ultraviolet photodissociation. Dust shielding, and replenishment of both gas and small dust from the outer disk, may also play a role in sustaining the water reservoir12. Our observations also reveal a strong variability of the mid-infrared spectral energy distribution, pointing to a change of inner disk geometry.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Perotti, G.; Max-Planck-Institute for Astronomy, Heidelberg
Christiaens, Valentin ; Université de Liège - ULiège > Unités de recherche interfacultaires > Space sciences, Technologies and Astrophysics Research (STAR)
Henning, Th.; Max-Planck-Institute for Astronomy, Heidelberg
Tabone, B.; Institut d'Astrophysique Spatiale
Waters, L. B. F. M.; Radboud University Nijmegen, Department of Astronomy and Physics, Netherlands Institute for Space Research
Kamp, I.; Kapteyn Astronomical Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
Olofsson, G.; AlbaNova University Center
Grant, S. L.; Max-Planck-Institute for Extraterrestrial Physics, Garching
Gasman, D.; Katholieke University of Leuven, Astronomical Institute
Bouwman, J.; Max-Planck-Institute for Astronomy, Heidelberg
Samland, M.; Max-Planck-Institute for Astronomy, Heidelberg
Franceschi, R.; Max-Planck-Institute for Astronomy, Heidelberg
van Dishoeck, E. F.; Max-Planck-Institute for Extraterrestrial Physics, Garching, Leiden Observatory
Schwarz, K.; Max-Planck-Institute for Astronomy, Heidelberg
Güdel, M.; Max-Planck-Institute for Astronomy, Heidelberg, -, ETH Zurich, Department of Physics
Lagage, P. -O.; CEA Saclay, Service d'Astrophysique
Ray, T. P.; Dublin Institute for Advanced Studies, Ireland
Vandenbussche, B.; Katholieke University of Leuven, Astronomical Institute
Abergel, A.; Institut d'Astrophysique Spatiale
Absil, Olivier ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
Arabhavi, A. M.; Kapteyn Astronomical Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
Argyriou, I.; Katholieke University of Leuven, Astronomical Institute
Barrado, D.; Centro de Astrobiología (CAB), CSIC-INTA, Villanueva de la Cañada, Spain
Boccaletti, A.; Observatoire de Paris, Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique
Caratti o Garatti, A.; Dublin Institute for Advanced Studies, Ireland, Astronomical Observatory of Capodimonte
Geers, V.; Royal Observatory Edinburgh
Glauser, A. M.; ETH Zurich, Department of Physics
Justannont, K.; Onsala Space Observatory
Lahuis, F.; Netherlands Institute for Space Research
Mueller, M.; Kapteyn Astronomical Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands
Nehmé, C.; CEA Saclay, Service d'Astrophysique
Pantin, E.; CEA Saclay, Service d'Astrophysique
Scheithauer, S.; Max-Planck-Institute for Astronomy, Heidelberg
Waelkens, C.; Katholieke University of Leuven, Astronomical Institute
Guadarrama, R.; Dept. of Astrophysics, University of Vienna, Vienna, Austria
Jang, H.; Radboud University Nijmegen, Department of Astronomy and Physics
Kanwar, J.; Kapteyn Astronomical Institute, Rijksuniversiteit Groningen, Groningen, the Netherlands, Space Research Institute, Austrian Academy of Sciences, Graz, Austria, TU Graz, Fakultät für Mathematik, Physik und Geodäsie, Graz, Austria
Morales-Calderón, M.; Centro de Astrobiología (CAB), CSIC-INTA, Villanueva de la Cañada, Spain
Pawellek, N.; Dept. of Astrophysics, University of Vienna, Vienna, Austria
Rodgers-Lee, D.; Dublin Institute for Advanced Studies, Ireland
Schreiber, J.; Max-Planck-Institute for Astronomy, Heidelberg
Colina, L.; Centro de Astrobiología (CAB, CSIC-INTA), Carretera de Ajalvir, Torrejón de Ardoz, Spain
Greve, T. R.; DTU Physics, Lyngby
Östlin, G.; Stockholm University, Department of Astronomy
Mulders, G. D., Pascucci, I., Apai, D. & Ciesla, F. J. The Exoplanet Population Observation Simulator. I. The inner edges of planetary systems. Astron. J. 156, 24 (2018).
Ciesla, F. J. & Cuzzi, J. N. The evolution of the water distribution in a viscous protoplanetary disk. Icarus 181, 178–204 (2006).
Eistrup, C. & Henning, T. Chemical evolution in ices on drifting, planet-forming pebbles. Astron. Astrophys. 667, A60 (2022).
Krijt, S. et al. Chemical habitability: supply and retention of life’s essential elements during planet formation. Preprint https://arxiv.org/abs/2203.10056 (2022).
Bethell, T. & Bergin, E. Formation and survival of water vapor in the terrestrial planet-forming region. Science 326, 142–153 (2009).
Glassgold, A. E. et al. Formation of water in the warm atmospheres of protoplanetary disks. Astrophys. J. 701, 1675–1677 (2009).
Banzatti, A. et al. Hints for icy pebble migration feeding an oxygen-rich chemistry in the inner planet-forming region of disks. Astrophys. J. 903, 124 (2020).
Keppler, M. et al. Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70. Astron. Astrophys. 617, A44 (2018).
Haffert, S. Y. et al. Two accreting protoplanets around the young star PDS 70. Nat. Astron. 3, 749–754 (2019).
Long, Z. C. et al. Differences in the gas and dust distribution in the transitional disk of a Sun-like young star, PDS 70. Astron. Astrophys. 858, 112 (2018).
Keppler, M. et al. Highly structured disk around the planet host PDS 70 revealed by high-angular resolution observations with ALMA. Astron. Astrophys. 625, A118 (2019).
Benisty, M. et al. A circumplanetary disk around PDS70c. Astrophys. J. Lett. 916, L2 (2021).
Rieke, G. H. et al. The Mid-Infrared Instrument for the James Webb Space Telescope, I: introduction. Publ. Astron. Soc. Pac. 127, 584 (2015).
Wright, G. S. et al. The Mid-Infrared Instrument for the James Webb Space Telescope, II: design and build. Publ. Astron. Soc. Pac. 127, 595 (2015).
Wells, M. et al. The Mid-Infrared Instrument for the James Webb Space Telescope, VI: the medium resolution spectrometer. Publ. Astron. Soc. Pac. 127, 646 (2015).
Kessler-Silacci, J. et al. c2d Spitzer IRS spectra of disks around T Tauri stars. I. Silicate emission and grain growth. Astrophys. J. 639, 275–291 (2006).
Furlan, E. et al. A survey and analysis of Spitzer infrared spectrograph spectra of T Tauri Stars in Taurus. Astrophys. J. 165, 568–605 (2006).
Argyriou, I. et al. JWST MIRI flight performance: the medium-resolution spectrometer. Preprint at https://arxiv.org/abs/2303.13469 (2023).
Muzerolle, J. et al. Evidence for dynamical changes in a transitional protoplanetary disk with mid-infrared variability. Astrophys. J. Lett. 704, L15–L19 (2009).
Espaillat, C. et al. A Spitzer IRS study of infrared variability in transitional and pre-transitional disks around T Tauri stars. Astrophys. J. 728, 49 (2011).
Manara, C. F. et al. Constraining disk evolution prescriptions of planet population synthesis models with observed disk masses and accretion rates. Astron. Astrophys. 631, L2 (2019).
Skinner, S. L. & Audard, M. HST UV spectroscopy of the planet-hosting T Tauri star PDS 70. Astrophys. J. 938, 134 (2022).
Stimpfl, H. An ångström-sized window on the origin of water in the inner Solar System: Atomistic simulation of adsorption of water on olivine. J. Cryst. Growth 294, 83–95 (2006).
Genda, H. & Ikoma, M. Origin of the ocean on the Earth: early evolution of water D/H in a hydrogen-rich atmosphere. Icarus 194, 42–52 (2008).
Salyk, C. et al. A Spitzer survey of mid-infrared molecular emission from protoplanetary disks. II. Correlations and local thermal equilibrium models. Astrophys. J. 731, 130 (2011).
Pontoppidan, K. M. et al. A Spitzer survey of mid-infrared molecular emission from protoplanetary disks. I. Detection rates. Astrophys. J. 720, 887–903 (2010).
Blevins, S. M. et al. Measurements of water surface snow lines in classical protoplanetary disks. Astrophys. J. 818, 22 (2016).
Portilla-Revelo B. et al. Constraining the gas distribution in the PDS 70 disk as a method to assess the effect of planet-disk interactions. Preprint at https://arxiv.org/abs/2306.16850 (2023).
Salyk, C. et al. Detection of water vapor in the terrestrial planet forming region of a transition disk. Astrophys. J. Lett. 810, L24 (2015).
Manara, C. F. et al. Gas content of transitional disks: a VLT/X-Shooter study of accretion and winds. Astron. Astrophys. 568, A18 (2014).
Oliveira, I. et al. A Spitzer Survey of protoplanetary disk dust in the Young Serpens Cloud: how do dust characteristics evolve with time? Astrophys. J. 714, 778–798 (2010).
Brown, J. M. et al. Cold disks: Spitzer spectroscopy of disks around young stars with large gaps. Astrophys. J. Lett. 664, L107–L110 (2007).
Furlan, E. et al. Disk evolution in the three nearby star-forming regions of Taurus, Chamaeleon, and Ophiuchus. Astrophys. J. 703, 1964–1983 (2009).
Banzatti, A. et al. The kinematics and excitation of infrared water vapor emission from planet-forming disks: results from spectrally-resolved surveys and guidelines for JWST spectra. Astron. J. 165, 72 (2023).
Bouvier, J. et al. Investigating the magnetospheric accretion process in the young pre-transitional disk system DoAr 44 (V2062 Oph). A multiwavelength interferometric, spectropolarimetric, and photometric observing campaign. Astron. Astrophys. 643, A99 (2020).
Gaia Collaboration. Gaia Data Release 2. Summary of the contents and survey properties. Astron. Astrophys. 616, A1 (2018).
Müller, A. et al. Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk. Astron. Astrophys. 617, L2 (2018).
Gregorio-Hetem, J. & Hetem, A. Classification of a selected sample of weak T Tauri stars. Mon. Not. R. Astron. Soc. 336, 197–206 (2002).
Metchev, S. A., Hillenbrand, L. A. & Meyer, M. R. Ten micron observations of nearby young stars. Astrophys. J. 600, 435–450 (2004).
Riaud, P. et al. Coronagraphic imaging of three weak-line T Tauri stars: evidence of planetary formation around PDS 70. Astron. Astrophys. 458, 317–325 (2006).
Dong, R. et al. The structure of pre-transitional protoplanetary disks. I. Radiative transfer modeling of the disk+cavity in the PDS 70 system. Astrophys. J. 760, 111 (2012).
Bushouse, H. et al. JWST calibration pipeline. Zenodo 10.5281/zenodo.4037306 (2022).
Gomez Gonzalez, C. A. et al. VIP: vortex image processing package for high-contrast direct imaging. Astron. J. 154, 7 (2017).
Christiaens, V. et al. VIP: a Python package for high-contrast imaging. J. Open Source Softw. 8, 4774 (2023).
Gasman, D. et al. JWST MIRI/MRS in-flight absolute flux calibration and tailored fringe correction for unresolved sources. Astron. Astrophys. 673, A102 (2023).
Tabone, B. et al. A rich hydrocarbon chemistry and high C to O ratio in the inner disk around a very low-mass star. Nat. Astron. 10.1038/s41550-023-01965-3 (2023).
Labiano, A. et al. Wavelength calibration and resolving power of the JWST MIRI Medium Resolution Spectrometer. Astron. Astrophys. 656, A57 (2021).
Tennyson, J. et al. Experimental energy levels of the water molecule. Astron. Astrophys. 30, 735–831 (2001).
Salyk, C. slabspec: Python code for producing LTE slab model molecular spectra. Zenodo 10.5281/zenodo.4037306 (2020).
Grant, S. L. et al. MINDS. The detection of 13CO2 with JWST-MIRI indicates abundant CO2 in a protoplanetary disk. Astrophys. J. Lett. 947, L6 (2023).
Facchini, S. et al. The chemical inventory of the planet-hosting disk PDS 70. Astron. J. 162, 99 (2021).
Portilla-Revelo, B. et al. Self-consistent modelling of the dust component in protoplanetary and circumplanetary disks: the case of PDS 70. Astron. Astrophys. 658, A89 (2022).
Zhuravlev, L. T. The surface chemistry of amorphous silica. Zhuravlev model. Colloids Surf. A Physicochem. Eng. Asp. 173, 1–38 (2000).
Stevenson, C. M. & Novak, S. W. Obsidian hydration dating by infrared spectroscopy: method and calibration. J. Archaeol. Sci. 38, 171 (2011).
Juhász, A. et al. Do we really know the dust? Systematics and uncertainties of the mid-infrared spectral analysis methods. Astrophys. J. 695, 1024–1041 (2009).
Juhász, A. et al. Dust evolution in protoplanetary disks around Herbig Ae/Be stars—the Spitzer view. Astrophys. J. 721, 431–455 (2010).
Jäger, C. et al. Steps toward interstellar silicate mineralogy. VII. Spectral properties and crystallization behaviour of magnesium silicates produced by the sol-gel method. Astron. Astrophys. 408, 193–204 (2003).
Dorschner, J. et al. Steps toward interstellar silicate mineralogy. II. Study of Mg-Fe-silicate glasses of variable composition. Astron. Astrophys. 300, 503 (1995).
Sogawa, H. et al. Infrared reflection spectra of forsterite crystal. Astron. Astrophys. 451, 357–361 (2006).
Jäger, C., Mutschke, H. & Henning, Th. Optical properties of carbonaceous dust analogues. Astron. Astrophys. 332, 291–299 (1998).
Henning, T. & Mutschke, H. Low-temperature infrared properties of cosmic dust analogues. Astron. Astrophys. 327, 743–754 (1997).
Feroz, F. & Hobson, M. P. Multimodal nested sampling: an efficient and robust alternative to Markov Chain Monte Carlo methods for astronomical data analyses. Mon. Not. R. Astron. Soc. 384, 449–463 (2008).
Buchner, J. et al. X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue. Astron. Astrophys. 564, A125 (2014).
Bouwman, J. et al. The formation and evolution of planetary systems: grain growth and chemical processing of dust in T Tauri systems. Astrophys. J. 683, 479–498 (2008).
