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Project Overview

Planets form and obtain their compositions in disks around young stars, and the outcome of this process is intimately linked to the disk chemical properties. The Molecules with ALMA at Planet-forming Scales (MAPS) ALMA Large Program (2018.1.01055.L) 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 4 spectral setups, which together cover ~50 lines from 20 different species. Together these observations provide constraints on a range of disk properties related to planet formation, including the relationship between dust and chemical substructures, C/N/O/S ratios and metallicity (O/H and C/H), organic reservoirs across the disks, disk photochemistry and deuterium fractionation, disk dust and gas surface densities, radial and vertical temperature structures, and 3D kinematics. 

The MAPS project is further described at project website includes a user-friendly script generator for downloading MAPS data products from the ALMA Archive.


Project Summary Table:

Project code Title PIs
2018.1.01055.L The Chemistry of Planet Formation Yuri Aikawa, Edwin A. Bergin, Viviana V. Guzmán, Karin I. Öberg, Catherine Walsh



The delivered data products are:

  • Self-calibrated uv data of all spectral windows (SPWs) (see MAPS I)

  • Continuum images for the four spectral settings (see MAPS XIV)

  • Image cubes at three angular resolutions for the Band 3 lines (0″.3 and 0″.5 circularized beams, and Briggs robust=0.5 non-circularized), and three angular resolutions for the Band 6 lines (0″.15, 0″.2, and 0″.3 circularized, and robust=0.5 non-circularized), as well as the associated Keplerian CLEAN masks, CLEAN models, and python scripts. The 0″.3 and robust=0.5 cubes are imaged both with and without continuum subtraction. All image cubes are delivered with and without primary beam correction, and with and without the so-called JvM correction applied (Jorsater, S., & van Moorsel, G. A. 1995, AJ, 110, 2037) (see MAPS II)

  • Value-Added Data Products (VADPs) for each line and spatial resolution: zeroth moment maps, rotation maps, peak intensity maps, and radial profiles (see MAPS III)

  • Emission surfaces for the strongest lines (see MAPS IV) 


All data products will be made available in the ALMA Science Archive. In the interim, you can also find them at



Yuri Aikawa (University of Tokyo), 

Edwin A. Bergin (University of Michigan), 

Viviana V. Guzmán (Pontificia Universidad Católica de Chile), 

Karin I. Öberg (Center for Astrophysics | Harvard & Smithsonian),

Catherine Walsh (University of Leeds)



Felipe Alarcón (University of Michigan),

Sean M. Andrews (Center for Astrophysics | Harvard & Smithsonian),

Jaehan Bae (University of Florida),

Jennifer B. Bergner (University of Chicago)

Yann Boehler (Univ. Grenoble Alpes),

Alice S. Booth (Leiden Observatory, Leiden University), 

Arthur D. Bosman (University of Michigan),

Jenny K. Calahan (University of Michigan),

Gianni Cataldi (National Astronomical Observatory of Japan / University of Tokyo),

L. Ilsedore Cleeves (University of Virginia),

Ian Czekala (Pennsylvania State University),

Kenji Furuya (National Astronomical Observatory of Japan),

Jane Huang (University of Michigan),

John D. Ilee (University of Leeds),

Nicolas T. Kurtovic (Max-Planck-Institut für Astronomie),

Romane Le Gal (IPAG / IRAM / Univ. Grenoble Alpes),

Yao Liu (Purple Mountain Observatory & Key Laboratory for Radio Astronomy),

Charles J. Law (Center for Astrophysics | Harvard & Smithsonian),

Ryan A. Loomis (National Radio Astronomy Observatory),

Feng Long (Center for Astrophysics | Harvard & Smithsonian),

François Ménard (Univ. Grenoble Alpes),

Hideko Nomura (National Astronomical Observatory of Japan),

Laura M. Pérez (Universidad de Chile),

Chunhua Qi (Center for Astrophysics | Harvard & Smithsonian),

Kamber R. Schwarz (University of Arizona / Max-Planck-Institut für Astronomie),

Anibal Sierra (Universidad de Chile),

Daniela Soto (Pontificia Universidad Católica de Chile),

Richard Teague (Center for Astrophysics | Harvard & Smithsonian),

Takashi Tsukagoshi (National Astronomical Observatory of Japan)

Yoshihide Yamato (University of Tokyo)

Merel L. R. van 't Hoff (University of Michigan)

Abygail R. Waggoner (University of Virginia)

David J. Wilner (Center for Astrophysics | Harvard & Smithsonian),

Ke Zhang (University of Wisconsin-Madison)



Öberg K.I., Guzmán, V.V., Walsh, C. et al. MAPS I. Program Overview and Highlights

Czekala, I., Loomis, R.A., Teague, R. et al. MAPS II. CLEAN Strategies for Synthesizing Images of Molecular Line Emission in Protoplanetary Disks

Law, C.J., Loomis, R.A., Teague, R. et al. MAPS III. Characteristics of Radial Chemical Substructures

Law, C.J., Teague, R., Loomis, R.A. et al. MAPS IV. Emission Surfaces and Vertical Distribution of Molecules

Zhang, K., Booth, A.S., Law, C.J. et al. MAPS V. CO Gas Distributions

Guzmán, V.V., Bergner, J.B., Law, C.J. et al. MAPS VI. Distribution of the Small Organics HCN, C2H, and H2CO

Bosman, A.D., Alarcón, F., Bergin, E.A. et al. MAPS VII. Substellar O/H and C/H and Superstellar C/O in Planet-feeding Gas

Alarcón, F., Bosman, A.D., Bergin, E.A. et al. MAPS VIII. CO Gap in AS 209 ⁠– Gas Depletion or Chemical Processing?

Ilee, J.D., Walsh, C., Booth, A.S. et al. MAPS IX. Distribution and Properties of the Large Organic Molecules HC3N, CH3CN, and c-C3H2

Cataldi, G., Yamato, Y., Aikawa, Y. et al. MAPS X. Studying Deuteration at High Angular Resolution toward Protoplanetary Disks

Bergner, J.B., Öberg, K.I., Guzmán, V.V. et al. MAPS XI. CN and HCN as Tracers of Photochemistry in Disks

Le Gal, R., Öberg, K.I., Teague, R. et al. MAPS XII. Inferring the C/O and S/H Ratios in Protoplanetary Disks with Sulfur Molecules

Aikawa, Y., Cataldi, G, Yamato, Y. et al. MAPS XIII. HCO+ and Disk Ionization Structure

Sierra, A., Pérez, L.M., Guzmán, V.V. et al. MAPS XIV. Revealing Disk Substructures in Multiwavelength Continuum Emission

Bosman, A.D., Bergin, E.A., Loomis, R. A. et al. MAPS XV. Tracing Proto-planetary Disk Structure within 20 au

Booth, A.S., Benoît, T., Ilee, J.D., et al. MAPS XVI. Characterizing the Impact of the Molecular Wind on the Evolution of the HD 163296 System

Calahan, J.K., Bergin, E.A., Zhang, K., et al. MAPS XVII. Determining the 2D Thermal Structure of the HD 163296 Disk

Teague, R., Bae, J., Aikawa, Y., et al. MAPS XVIII. Kinematic Substructures in the Disks of HD 163296 and MWC 480

Huang, J., Bergin, E.A., Öberg, K.I., et al. MAPS XIX. Spiral Arms, a Tail, and Diffuse Structures Traced by CO around the GM Aur Disk

Schwarz, K.R., Calahan, J.K., Zhang, K. et al. MAPS XX. The Massive Disk around GM Aurigae