Browsing by Author "Boehler, Yann"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    Molecules with ALMA at Planet-forming Scales (MAPS). I. Program Overview and Highlights
    (2021) Oberg, Karin, I; Guzman, Viviana V.; Walsh, Catherine; Aikawa, Yuri; Bergin, Edwin A.; Law, Charles J.; Loomis, Ryan A.; Alarcon, Felipe; Andrews, Sean M.; Bae, Jaehan; Bergner, Jennifer B.; Boehler, Yann; Booth, Alice S.; Bosman, Arthur D.; Calahan, Jenny K.; Cataldi, Gianni; Cleeves, L. Ilsedore; Czekala, Ian; Furuya, Kenji; Huang, Jane; Ilee, John D.; Kurtovic, Nicolas T.; Le Gal, Romane; Liu, Yao; Long, Feng; Menard, Francois; Nomura, Hideko; Perez, Laura M.; Qi, Chunhua; Schwarz, Kamber R.; Sierra, Anibal; Teague, Richard; Tsukagoshi, Takashi; Yamato, Yoshihide; van't Hoff, Merel L. R.; Waggoner, Abygail R.; Wilner, David J.; Zhang, Ke
    Planets form and obtain their compositions in dust- and gas-rich disks around young stars, and the outcome of this process is intimately linked to the disk chemical properties. The distributions of molecules across disks regulate the elemental compositions of planets, including C/N/O/S ratios and metallicity (O/H and C/H), as well as access to water and prebiotically relevant organics. Emission from molecules also encodes information on disk ionization levels, temperature structures, kinematics, and gas surface densities, which are all key ingredients of disk evolution and planet formation models. The Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program was designed to expand our understanding of the chemistry of planet formation by exploring disk chemical structures down to 10 au scales. The MAPS program focuses on five disks-around IM Lup, GM Aur, AS 209, HD 163296, and MWC 480-in which dust substructures are detected and planet formation appears to be ongoing. We observed these disks in four spectral setups, which together cover similar to 50 lines from over 20 different species. This paper introduces the Astrophysical Journal Supplement's MAPS Special Issue by presenting an overview of the program motivation, disk sample, observational details, and calibration strategy. We also highlight key results, including discoveries of links between dust, gas, and chemical substructures, large reservoirs of nitriles and other organics in the inner disk regions, and elevated C/O ratios across most disks. We discuss how this collection of results is reshaping our view of the chemistry of planet formation.
  • No Thumbnail Available
    Item
    Molecules with ALMA at Planet-forming Scales (MAPS). III. Characteristics of Radial Chemical Substructures
    (2021) Law, Charles J.; Loomis, Ryan A.; Teague, Richard; Oberg, Karin, I; Czekala, Ian; Andrews, Sean M.; Huang, Jane; Aikawa, Yuri; Alarcon, Felipe; Bae, Jaehan; Bergin, Edwin A.; Bergner, Jennifer B.; Boehler, Yann; Booth, Alice S.; Bosman, Arthur D.; Calahan, Jenny K.; Cataldi, Gianni; Cleeves, L. Ilsedore; Furuya, Kenji; Guzman, Viviana V.; Ilee, John D.; Le Gal, Romane; Liu, Yao; Long, Feng; Menard, Francois; Nomura, Hideko; Qi, Chunhua; Schwarz, Kamber R.; Sierra, Anibal; Tsukagoshi, Takashi; Yamato, Yoshihide; van't Hoff, Merel L. R.; Walsh, Catherine; Wilner, David J.; Zhang, Ke
    The Molecules with ALMA at Planet-forming Scales (MAPS) Large Program provides a detailed, high-resolution (similar to 10-20 au) view of molecular line emission in five protoplanetary disks at spatial scales relevant for planet formation. Here we present a systematic analysis of chemical substructures in 18 molecular lines toward the MAPS sources: IM Lup, GM Aur, AS 209, HD 163296, and MWC 480. We identify more than 200 chemical substructures, which are found at nearly all radii where line emission is detected. A wide diversity of radial morphologies-including rings, gaps, and plateaus-is observed both within each disk and across the MAPS sample. This diversity in line emission profiles is also present in the innermost 50 au. Overall, this suggests that planets form in varied chemical environments both across disks and at different radii within the same disk. Interior to 150 au, the majority of chemical substructures across the MAPS disks are spatially coincident with substructures in the millimeter continuum, indicative of physical and chemical links between the disk midplane and warm, elevated molecular emission layers. Some chemical substructures in the inner disk and most chemical substructures exterior to 150 au cannot be directly linked to dust substructure, however, which indicates that there are also other causes of chemical substructures, such as snowlines, gradients in UV photon fluxes, ionization, and radially varying elemental ratios. This implies that chemical substructures could be developed into powerful probes of different disk characteristics, in addition to influencing the environments within which planets assemble. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.
  • No Thumbnail Available
    Item
    Molecules with ALMA at Planet-forming Scales (MAPS). XVIII. Kinematic Substructures in the Disks of HD 163296 and MWC 480
    (2021) Teague, Richard; Bae, Jaehan; Aikawa, Yuri; Andrews, Sean M.; Bergin, Edwin A.; Bergner, Jennifer B.; Boehler, Yann; Booth, Alice S.; Bosman, Arthur D.; Cataldi, Gianni; Czekala, Ian; Guzman, Viviana V.; Huang, Jane; Ilee, John D.; Law, Charles J.; Le Gal, Romane; Long, Feng; Loomis, Ryan A.; Menard, Francois; Oberg, Karin, I; Perez, Laura M.; Schwarz, Kamber R.; Sierra, Anibal; Walsh, Catherine; Wilner, David J.; Yamato, Yoshihide; Zhang, Ke
    We explore the dynamical structure of the protoplanetary disks surrounding HD 163296 and MWC 480 as part of the Molecules with ALMA at Planet-forming Scales (MAPS) large program. Using the J = 2-1 transitions of (CO)-C-12, (CO)-C-13, and (CO)-O-18 imaged at spatial resolutions of similar to 0.'' 15 and with a channel spacing of 200 m s(-1), we find perturbations from Keplerian rotation in the projected velocity fields of both disks (less than or similar to 5% of the local Keplerian velocity), suggestive of large-scale (tens of astronomical units in size), coherent flows. By accounting for the azimuthal dependence on the projection of the velocity field, the velocity fields were decomposed into azimuthally averaged orthogonal components, v ( phi ), v ( r ), and v ( z ). Using the optically thick (CO)-C-12 emission as a probe of the gas temperature, local variations of approximate to 3 K (approximate to 5% relative changes) were observed and found to be associated with the kinematic substructures. The MWC 480 disk hosts a suite of tightly wound spiral arms. The spirals arms, in conjunction with the highly localized perturbations in the gas velocity structure (kinematic planetary signatures), indicate a giant planet, similar to 1 M (Jup), at a radius of approximate to 245 au. In the disk of HD 163296, the kinematic substructures were consistent with previous studies of Pinte et al. and Teague et al. advocating for multiple similar to 1 M (Jup) planets embedded in the disk. These results demonstrate that molecular line observations that characterize the dynamical structure of disks can be used to search for the signatures of embedded planets. This paper is part of the MAPS special issue of the Astrophysical Journal Supplement.