CaltechAUTHORS
Published August 1, 2020 | Version Published + Accepted Version
Journal Article Open

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

Creators

  • 1. ROR icon California Institute of Technology
  • 2. ROR icon University of Victoria
  • 3. ROR icon Leiden University
  • 4. ROR icon European Southern Observatory
  • 5. ROR icon Space Telescope Science Institute
  • 6. ROR icon Institut de Planétologie et d'Astrophysique de Grenoble
  • 7. ROR icon University of Chile
  • 8. ROR icon University of California, Berkeley
  • 9. ROR icon French National Centre for Scientific Research
  • 10. ROR icon ETH Zurich
  • 11. ROR icon Arcetri Astrophysical Observatory
  • 12. ROR icon Goddard Space Flight Center
  • 13. ROR icon University of Liège
  • 14. ROR icon University of Arizona

Abstract

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⁺¹⁸₋₁₄ 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.

Additional Information

© 2020 The American Astronomical Society. Received 2020 May 8; revised 2020 July 8; accepted 2020 July 8; published 2020 July 29. We thank the anonymous referee for comments that improved the clarity of this Letter, and Cassandra Hall for useful discussions. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 060.A-9389(A) and 104.C-0472(A). B.R. thanks Christian Ginski for discussions on shadowing effects, Rémi Soummer for initiating the Archival Legacy Investigations of Circumstellar Environments (ALICE) project that set up the stage for R18 and this Letter. T.E. was supported in part by NASA Grants NNX15AD95G/NEXSS, NNX15AC89G, and NSF AST-1518332. A.L.M. acknowledges the financial support of the F.R.S.-FNRS through a postdoctoral researcher grant. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facilities: Very Large Telescope (SPHERE) - , Keck:II (NIRC2). - Software: diskmap (Stolker et al. 2016), IRDAP (van Holstein et al. 2017, 2020), scipy (Virtanen et al. 2020).

Attached Files

Published - Ren_2020_ApJL_898_L38.pdf

Accepted Version - 2007.04980.pdf

Files

2007.04980.pdf

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Additional details

Identifiers

Eprint ID
104634
Resolver ID
CaltechAUTHORS:20200729-095324179

Related works

Describes
https://arxiv.org/abs/2007.04980 (URL)

Funding

NASA
NNX15AD95G
NASA
NNX15AC89G
NSF
AST-1518332
Fonds de la Recherche Scientifique (FNRS)
W. M. Keck Foundation

Dates

Created
2020-07-29
Created from EPrint's datestamp field
Updated
2021-11-16
Created from EPrint's last_modified field

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Caltech groups
Astronomy Department