J/A+A/618/A151 HD 172555 polarimetric images (Engler+, 2018) ================================================================================ Detection of scattered light from the hot dust in HD 172555. Engler N., Schmid H.M., Quanz S.P., Avenhaus H., Bazzon A. =2018A&A...618A.151E (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Stars, nearby ; Polarization Keywords: planetary systems - scattering - stars: individual object: HD 172555 - techniques: high angular resolution - techniques: polarimetric Abstract: Debris disks or belts are important signposts for the presence of colliding planetesimals and, therefore, for ongoing planet formation and evolution processes in young planetary systems. Imaging of debris material at small separations from the star is very challenging but provides valuable insights into the spatial distribution of the so-called hot dust produced by solid bodies located in or near the habitable zone. We report the first detection of scattered light from the hot dust around the nearby (d=28.33pc) A star HD 172555. We want to constrain the geometric structure of the detected debris disk using polarimetric differential imaging (PDI) with a spatial resolution of 25mas and an inner working angle of about 0.1". We measured the polarized light of HD 172555, with SPHERE/ZIMPOL, in the very broadband (VBB) or RI filter ({lambda}c=735nm, {Delta}{lambda}290nm) for the projected separations between 0.08" (2.3au) and 0.77" (22au). We constrained the disk parameters by fitting models for scattering of an optically thin dust disk taking the limited spatial resolution and coronagraphic attenuation of our data into account. The geometric structure of the disk in polarized light shows roughly the same orientation and outer extent as obtained from thermal emission at 18{mu}m. Our image indicates the presence of a strongly inclined (i~=103.5{deg}), roughly axisymmetric dust belt with an outer radius in the range between 0.3" (8.5au) and 0.4" (11.3au). An inner disk edge is not detected in the data. We derive a lower limit for the polarized flux contrast ratio for the disk of (Fpol)disk/F*>(6.2+/-0.6)x10^-5^ in the VBB filter. This ratio is small, only ~9%, when compared to the fractional infrared flux excess (~=7.2x10^-4^). The model simulations show that more polarized light could be produced by the dust located inside ~=2au, which cannot be detected with the instrument configuration used. Our data confirm previous infrared imaging and provide a higher resolution map of the system, which could be further improved with future observations. Description: The fits files contain the reduced SPHERE-ZIMPOL polarimetric observations of HD 172555 in the Very Broad Band filter (lambda = 735 nm) on June 26th (observation 177) and Sep. 9th (observation 249, selected frames), 2015. These are the total intensity Iq and Iu (Stokes I) and Stokes Q and U images shown in the second row (observation 177) and fourth row (observation 249) of Fig. B.1 of the paper. Images are not derotated (field offset) and the True North offset is not corrected. To get North up and East to the left, images of observation 177 should be derotated by 120 deg counterclockwise. To correct for the True North offset, images of both observations (177 and 249) should be rotated by 2{deg} clockwise. Each image has 1024x1024 pixels with one pixel corresponding to 3.6x3.6 mas on sky. Objects: -------------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------------- 18 45 26.90 -64 52 16.5 HD 172555 = HR 7012 -------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file list.dat 111 8 List of fits images fits/* . 8 Individual fits images -------------------------------------------------------------------------------- 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- 23 I4 --- Nx Number of pixels along X-axis 25- 28 I4 --- Ny Number of pixels along Y-axis 30- 33 I4 Kibyte size Size of FITS file 35- 43 A9 --- FileName Name of FITS file, in subdirectory fits 45-111 A67 --- Title Title of the FITS file -------------------------------------------------------------------------------- Acknowledgements: Natalia Engler, englern(at)phys.ethz.ch ================================================================================ (End) N. Engler [ETH Zurich, Switzerland], P. Vannier [CDS] 31-Jul-2018