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J/A+A/613/L5        Hα emitting sources around MWC758    (Huelamo+, 2018)

Searching for Hα emitting sources around MWC758: SPHERE/ZIMPOL high-contrast imaging. Huelamo N., Chauvin G., Schmid H.M., Quanz S.P., Whelan E., Lillo-Box J., Barrado D., Montesinos B., Alcala J.M., Benisty M., de Gregorio-Monsalvo I., Mendigutia I., Bouy H., Merin B., de Boer J., Garufi A., Pantin E. <Astron. Astrophys. 613, L5 (2018)> =2018A&A...613L...5H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Be ; Stars, pre-main sequence ; Photometry, infrared Keywords: stars: pre-main sequence - stars: planetary systems - stars: individual: MWC758 - accretion, accretion disks - techniques: high angular resolution Abstract: MWC758 is a young star surrounded by a transitional disk. The disk shows an inner cavity and spiral arms that could be caused by the presence of protoplanets. Recently, a protoplanet candidate has been detected around MWC758 through high-resolution L'-band observations. The candidate is located inside the disk cavity at a separation of 111 mas from the central star, and at an average position angle of 165.5°. We aim at detecting accreting protoplanet candidates within the disk of MWC758 through spectral angular differential imaging observations in the optical regime. In particular, we explore the emission at the position of the detected planet candidate. We have performed simultaneous adaptive optics observations in the Hα line and the adjacent continuum using SPHERE/ZIMPOL at the Very Large Telescope (VLT). The data analysis does not reveal any Hα signal around the target. The derived contrast curve in the B_Ha filter allows us to derive a 5σ upper limit of 7.6mag at 111mas, the separation of the previously detected planet candidate. This contrast translates into a Hα line luminosity of LHα≲5*10-5L at 111mas. Assuming that LHα scales with Lacc as in Classical T Tauri stars as a first approximation, we can estimate an accretion luminosity of Lacc<3.7*10-4L for the protoplanet candidate. For the predicted mass range of MWC758b, 0.5-5MJup, this implies accretion rates smaller than dM/dt<3.4*(10-8-10-9)M[sun/yr, for an average planet radius of 1.1 RJup. Therefore, our estimates are consistent with the predictions of accreting circumplanetary accretion models for Rin=1RJup. The ZIMPOL line luminosity is consistent with the Hα upper limit predicted by these models for truncation radii ≲3.2RJup. The non-detection of any Hαemitting source in the ZIMPOL images does not allow us to unveil the nature of the L' detected source. Either it is a protoplanet candidate or a disk asymmetry. Description: The SPHERE Open Time observations (096.C-0267.A) were obtained on December 30, 2015. The ZIMPOL instrument of SPHERE was used in spectral and angular differential imaging modes. In addition to the pupil stabilized mode, ZIMPOL simultaneously imaged MWC758 in two different filters: B_Ha (λc=655.6nm and δλ=5.5nm) and Cnt_Ha (λc=644.9nm and δλ=4.1nm). We obtained 190 individual exposures of 60 seconds each, resulting in a total exposure time of 3 hours on-source (from 02:20UT to 05:24 UT). Objects: ----------------------------------------------- RA (2000) 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 162 3 List of fits images fits/* 0 3 Individual fits images
See also: J/A+A/578/L6 : Polarized images of MWC758 (Benisty+, 2015) J/A+A/611/A74 : Angular differential imaging of MCW 758 (Reggiani+, 2018) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 22 I3 --- Nx Number of pixels along X-axis 24- 26 I3 --- Ny Number of pixels along Y-axis 28- 30 I3 Kibyte size Size of FITS file 32- 72 A41 --- FileName Name of FITS file, in subdirectory fits 74-162 A89 --- Title Title of the FITS file
Acknowledgements: Nuria Huelamo, nhuelamo(at)cab.inta-csic.es
(End) Patricia Vannier [CDS] 04-Jun-2018
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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