Dynamical Evidence of a Spiral Arm-driving Planet in the MWC 758 Protoplanetary Disk

Bin Ren, Ruobing Dong, Rob G. Van Holstein, Jean Baptiste Ruffio, Benjamin A. Calvin, Julien H. Girard, Myriam Benisty, Anthony Boccaletti, Thomas M. Esposito, lodie Choquet, Dimitri Mawet, Laurent Pueyo, Tomas Stolker, Eugene Chiang, Jozua De Boer, John H. Debes, Antonio Garufi, Carol A. Grady, Dean C. Hines, Anne Lise MaireFran ois Ménard, Maxwell A. Millar-Blanchaer, Marshall D. Perrin, Charles A. Poteet, Glenn Schneider

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27 Scopus citations


More than a dozen young stars host spiral arms in their surrounding protoplanetary disks. The excitation mechanisms of such arms are under debate. The two leading hypotheses - companion-disk interaction and gravitational instability (GI) - predict distinct motion for spirals. By imaging the MWC 758 spiral arm system at two epochs spanning ∼5 yr using the SPHERE instrument on the Very Large Telescope, we test the two hypotheses for the first time. We find that the pattern speeds of the spirals are not consistent with the GI origin. Our measurements further evince the existence of a faint "missing planet"driving the disk arms. The average spiral pattern speed is 0. 22 0. 03 yr-1, pointing to a driver at 172-14+18 au around a 1.9 M central star if it is on a circular orbit. In addition, we witness time-varying shadowing effects on a global scale that are likely originating from an inner disk.

Original languageEnglish (US)
Article numberL38
JournalAstrophysical Journal Letters
Issue number2
StatePublished - Aug 2020

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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  • VLT/SPHERE Y-band images of MWC 758 at two epochs

    Ren, B. (Creator), Dong, R. (Creator), Van Holstein, R. G. (Creator), Ruffio, J. (Creator), Calvin, B. A. (Creator), Girard, J. H. (Creator), Benisty, M. (Creator), Boccaletti, A. (Creator), Esposito, T. M. (Creator), Mawet, D. (Creator), Pueyo, L. (Creator), Stolker, T. (Creator), Chiang, E. (Creator), Boer, J. D. (Contributor), Debes, J. H. (Creator), Garufi, A. (Creator), Grady, C. A. (Creator), Hines, D. C. (Creator), Maire, A. (Creator), Ménard, F. O. (Contributor), Millar-Blanchaer, M. A. (Creator), Perrin, M. D. (Creator), Poteet, C. A. (Creator), Schneider, G. H. (Creator), Ren, B. (Creator), Choquet, E. (Creator), De Boer, J. (Creator), Maire, A. (Creator), Menard, F. (Creator), Millar-Blanchaer, M. A. (Creator) & Perrin, M. D. (Creator), Centre de Donnees Strasbourg (CDS), 2021


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