First resolved observations of a highly asymmetric debris disc around HD 160305 with VLT/SPHERE
Journal
Date Issued
2019
Author(s)
Perrot, Clément
•
Thebault, Philippe
•
Lagrange, Anne-Marie
•
Boccaletti, Anthony
•
Vigan, Arthur
•
•
Augereau, Jean-Charles
•
Bonnefoy, Mickael
•
Choquet, Élodie
•
Kral, Quentin
•
Loh, Alan
•
Maire, Anne-Lise
•
Ménard, François
•
•
Olofsson, Johan
•
•
Biller, Beth
•
Brandner, Wolfgang
•
Buenzli, Esther
•
Chauvin, Gaël
•
Cheetham, Anthony
•
Daemgen, Sebastien
•
Delorme, Philippe
•
Feldt, Markus
•
Lagadec, Eric
•
Langlois, Maud
•
Lannier, Justine
•
•
Mouillet, David
•
Peretti, Sébastien
•
Janin-Potiron, Pierre
•
Salter, Graeme
•
•
Roux, Alain
•
Llored, Marc
•
Buey, Jean-Tristan
•
Pavlov, Alexei
•
Weber, Luc
•
Petit, Cyril
Abstract
Context. Direct imaging of debris discs gives important information about their nature, their global morphology, and allows us to identify specific structures possibly in connection with the presence of gravitational perturbers. It is the most straightforward technique to observe planetary systems as a whole.
Aims: We present the first resolved images of the debris disc around the young F-type star HD 160305, detected in scattered light using the VLT/SPHERE instrument in the near infrared.
Methods: We used a post-processing method based on angular differential imaging and synthetic images of debris discs produced with a disc modelling code (GRaTer) to constrain the main characteristics of the disc around HD 160305. All of the point sources in the field of the IRDIS camera were analysed with an astrometric tool to determine whether they are bound objects or background stars.
Results: We detect a very inclined ( 82°) ring-like debris disc located at a stellocentric distance of about 86 au (deprojected width 27 au). The disc displays a brightness asymmetry between the two sides of the major axis, as can be expected from scattering properties of dust grains. We derive an anisotropic scattering factor g > 0.5. A second right-left asymmetry is also observed with respect to the minor axis. We measure a surface brightness ratio of 0.73 ± 0.18 between the bright and the faint sides. Because of the low signal-to-noise ratio (S/N) of the images we cannot easily discriminate between several possible explanations for this left-right asymmetry, such as perturbations by an unseen planet, the aftermath of the breakup of a massive planetesimal, or the pericenter glow effect due to an eccentric ring. Two epochs of observations allow us to reject the companionship hypothesis for the 15 point sources present in the field.
Aims: We present the first resolved images of the debris disc around the young F-type star HD 160305, detected in scattered light using the VLT/SPHERE instrument in the near infrared.
Methods: We used a post-processing method based on angular differential imaging and synthetic images of debris discs produced with a disc modelling code (GRaTer) to constrain the main characteristics of the disc around HD 160305. All of the point sources in the field of the IRDIS camera were analysed with an astrometric tool to determine whether they are bound objects or background stars.
Results: We detect a very inclined ( 82°) ring-like debris disc located at a stellocentric distance of about 86 au (deprojected width 27 au). The disc displays a brightness asymmetry between the two sides of the major axis, as can be expected from scattering properties of dust grains. We derive an anisotropic scattering factor g > 0.5. A second right-left asymmetry is also observed with respect to the minor axis. We measure a surface brightness ratio of 0.73 ± 0.18 between the bright and the faint sides. Because of the low signal-to-noise ratio (S/N) of the images we cannot easily discriminate between several possible explanations for this left-right asymmetry, such as perturbations by an unseen planet, the aftermath of the breakup of a massive planetesimal, or the pericenter glow effect due to an eccentric ring. Two epochs of observations allow us to reject the companionship hypothesis for the 15 point sources present in the field.
The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/626/A95Based on observations made with ESO Telescopes at the Paranal Observatory under programs ID 95.C-0298 and 97.C-0865.Note to the reader: The name of the author "Jean-Charles Ausgereau" was a mistake and has been corrected in "Jean-Charles Augereau" on 3 July 2019.
Volume
626
Start page
A95
Issn Identifier
0004-6361
Ads BibCode
2019A&A...626A..95P
Rights
open.access
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