J/A+A/611/A74 Angular differential imaging of MCW 758 (Reggiani+, 2018)
Discovery of a point-like source and a third spiral arm in the transition disk
around the Herbig Ae star MWC 758.
Reggiani M., Christiaens V., Absil O., Mawet D., Huby E., Choquet E.,
Gomez Gonzalez C.A., Ruane G., Femenia B., Serabyn E., Matthews K.,
Barraza M., Carlomagno B., Defrere D., Delacroix C., Habraken S.,
Jolivet A., Karlsson M., Orban de Xivry G., Piron P., Surdej J.,
Vargas Catalan E., Wertz O.
<Astron. Astrophys. 611, A74 (2018)>
=2018A&A...611A..74R 2018A&A...611A..74R (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Photometry, infrared
Keywords: protoplanetary disks - planet-disk interaction -
stars: pre-main sequence - stars: individual: MWC 758 (HD 36112)
Abstract:
Transition disks offer the extraordinary opportunity to look for newly
born planets and investigate the early stages of planet formation.
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.
Our high-contrast imaging observations show a bright
(ΔL'=7.0±0.3mag) point-like emission, south of MWC 758 at a
deprojected separation of ∼20au (r=0.111"±0.004") from the central
star. We also recover the two spiral arms (south-east and
north-west), already imaged by previous studies in polarized light,
and discover a third one to the south-west of the star. No additional
companions were detected in the system down to 5 Jupiter masses beyond
0.6" from the star.
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.
Description:
MWC 758 was observed twice with the Keck II telescope at W. M. Keck
Observatory, taking advantage of the L'-band vector vortex
coronagraph installed in the near-infrared camera and spectrograph
NIRC2
On October 24, 2015 we obtained 33 minutes (80 frames) of on-source
integration time and 129 of field rotation to allow for angular
differential imaging (ADI).
MWC 758 was then re-observed on October 24, 2016, following the same
observing strategy as for the first epoch of observations
Fits file for Fig. 1. Final L' band reduced images (after Principle
Component Analysis, PCA) of the two data sets, presented in the paper.
The complete data reduction can be found in the paper. 3 and 9 PCs
were used for the 2015 and 2016 data sets, respectively.
Objects:
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RA (ICRS) DE Designation(s)
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05 30 27.53 +25 19 57.1 MWC 758 = HD 36112
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 94 2 List of fits images
fits/* . 2 Individual fits images
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See also:
J/A+A/578/L6 : Polarized images of MWC758 (Benisty+, 2015)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000)
4- 5 I2 min RAm Right ascension (J2000)
7- 12 F6.3 s RAs Right ascension (J2000)
13 A1 --- DE- Declination sign (J2000)
14- 15 I2 deg DEd Declination (J2000)
17- 18 I2 arcmin DEm Declination (J2000)
20- 25 F6.3 arcsec DEs Declination (J2000)
27- 29 I3 --- Nx Number of pixels along X-axis
31- 33 I3 --- Ny Number of pixels along Y-axis
35- 37 I3 Kibyte size Size of FITS file
39- 51 A13 --- FileName Name of FITS file, in subdirectory fits
53- 94 A42 --- Title Title of the FITS file
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Acknowledgements:
Maddalena Reggiani, mreggiani(at)uliege.be
(End) Patricia Vannier [CDS] 04-Dec-2017