Discovery of a point-like source and a third spiral arm in the transition disk around the Herbig Ae star MWC 758
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Reggiani, M.
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Discovery of a point-like source and a third spiral arm in the transition disk around the Herbig Ae star MWC 758
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Abstract
Context. Transition disks offer the extraordinary opportunity to look for newly born planets and to investigate the early stages of planet formation.
Aims. In this context we observed the Herbig A5 star MWC 758 with the L'-band vector vortex coronagraph installed in the near-infrared camera and spectrograph NIRC2 at the Keck II telescope, with the aim of unveiling the nature of the spiral structure by constraining the presence of planetary companions in the system.
Methods. Our high-contrast imaging observations show a bright (Delta L' = 7.0 +/- 0.3 mag) point-like emission south of MWC 758 at a deprojected separation of similar to 20 au (r = 0 ''.111 +/- 0 ''.004) from the central star. We also recover the two spiral arms (southeast and northwest), already imaged by previous studies in polarized light, and discover a third arm to the southwest of the star. No additional companions were detected in the system down to 5 Jupiter masses beyond 0 ''.6 from the star.
Results. We propose that the bright L'-band emission could be caused by the presence of an embedded and accreting protoplanet, although the possibility of it being an asymmetric disk feature cannot be excluded. The spiral structure is probably not related to the protoplanet candidate, unless on an inclined and eccentric orbit, and it could be due to one (or more) yet undetected planetary companions at the edge of or outside the spiral pattern. Future observations and additional simulations will be needed to shed light on the true nature of the point-like source and its link with the spiral arms.
Patrocinador
European Research Council under the European Union (ERC)
337569
CONICYT through CONICYT-PCHA/Doctorado Nacional
2016-21161112
Millennium Science Initiative (Chilean Ministry of Economy)
RC130007
NSF Astronomy and Astrophysics Postdoctoral Fellowship
AST-1602444
NASA through Hubble Fellowship - STScI
HST-HF2-51355
NAS5-2655
NASA
HST-AR-12652
HST-GO-11136
HST-GO-13855
HST-GO-1331
STScI Director's Discretionary Research Funds
W. M. Keck Foundation
French Community of Belgium through an ARC
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Artículo de publicación ISI
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Astronomy & Astrophysics, 611, A74 (2018)
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