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J/A+A/611/A74       MWC 758 (HD 36112) PCA-ADI images          (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 (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: ---------------------------------------------------------- RA (ICRS) DE Designation(s) ---------------------------------------------------------- 05 30 27.53 +25 19 57.1 MWC 758 = HD 36112 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 94 2 List of fits images fits/* 0 2 Individual fits images
See also: J/A+A/578/L6 : Polarized images of MWC758 (Benisty+, 2015) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
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
Acknowledgements: Maddalena Reggiani, mreggiani(at)uliege.be
(End) Patricia Vannier [CDS] 04-Dec-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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