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dc.contributor.author
Lazzoni, Cecilia
dc.contributor.author
Meyer, M.
dc.contributor.author
Buenzli, Esther
dc.date.accessioned
2020-10-13T10:06:23Z
dc.date.available
2020-10-11T05:17:19Z
dc.date.available
2020-10-13T10:06:23Z
dc.date.issued
2020-09
dc.identifier.issn
0004-6361
dc.identifier.issn
1432-0746
dc.identifier.other
10.1051/0004-6361/201937290
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/445430
dc.description.abstract
Context. In recent decades, thousands of substellar companions have been discovered with both indirect and direct methods of detection. While the majority of the sample is populated by objects discovered using radial velocity and transit techniques, an increasing number have been directly imaged. These planets and brown dwarfs are extraordinary sources of information that help in rounding out our understanding of planetary systems. Aims. In this paper, we focus our attention on substellar companions detected with the latter technique, with the primary goal of investigating their close surroundings and looking for additional companions and satellites, as well as disks and rings. Any such discovery would shed light on many unresolved questions, particularly with regard to their possible formation mechanisms. Methods. To reveal bound features of directly imaged companions, whether for point-like or extended sources, we need to suppress the contribution from the source itself. Therefore, we developed a method based on the negative fake companion technique that first estimates the position in the field of view (FoV) and the flux of the imaged companion with high precision, then subtracts a rescaled model point spread function (PSF) from the imaged companion, using either an image of the central star or another PSF in the FoV. Next it performs techniques, such as angular differential imaging, to further remove quasi-static patterns of the star (i.e., speckle contaminants) that affect the residuals of close-in companions. Results. After testing our tools on simulated companions and disks and on systems that were chosen ad hoc, we applied the method to the sample of substellar objects observed with SPHERE during the SHINE GTO survey. Among the 27 planets and brown dwarfs we analyzed, most objects did not show remarkable features, which was as expected, with the possible exception of a point source close to DH Tau B. This candidate companion was detected in four different SPHERE observations, with an estimated mass of ∼1MJup, and a mass ratio with respect to the brown dwarf of 1• 10. This binary system, if confirmed, would be the first of its kind, opening up interesting questions for the formation mechanism, evolution, and frequency of such pairs. In order to address the latter, the residuals and contrasts reached for 25 companions in the sample of substellar objects observed with SPHERE were derived. If the DH Tau Bb companion is real, the binary fraction obtained is ∼7%, which is in good agreement with the results obtained for field brown dwarfs. Conclusions. While there may currently be many limitations affecting the exploration of bound features to directly imaged exoplanets and brown dwarfs, next-generation instruments from the ground and space (i.e., JWST, ELT, and LUVOIR) will be able to image fainter objects and, thus, drive the application of this technique in upcoming searches for exo-moons and circumplanetary disks. © 2020 ESO
en_US
dc.language.iso
en
en_US
dc.publisher
EDP Sciences
en_US
dc.subject
instrumentation: adaptive optics
en_US
dc.subject
methods: data analysis
en_US
dc.subject
methods: observational
en_US
dc.subject
techniques: image processing
en_US
dc.subject
planets and satellites: detection
en_US
dc.subject
planets and satellites: formation
en_US
dc.title
The search for disks or planetary objects around directly imaged companions: A candidate around DH Tauri B
en_US
dc.type
Journal Article
dc.date.published
2020-09-21
ethz.journal.title
Astronomy & Astrophysics
ethz.journal.volume
641
en_US
ethz.journal.abbreviated
Astron. Astrophys.
ethz.pages.start
A131
en_US
ethz.size
17 p.
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Les Ulis
en_US
ethz.publication.status
published
en_US
ethz.date.deposited
2020-10-11T05:17:33Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2020-10-13T10:06:35Z
ethz.rosetta.lastUpdated
2020-10-13T10:06:35Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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