1203.2619 (Timothy J. Rodigas et al.)

The Grey Needle: Large Grains in the HD 15115 Debris Disk from LBT/PISCES/Ks and LBTI/LMIRcam/L' Adaptive Optics Imaging    [PDF]

Timothy J. Rodigas, Philip M. Hinz, Jarron Leissenring, Vidhya Vaitheeswaran, Andrew J. Skemer, Michael Skrutskie, Kate Y. L. Su, Vanessa Bailey, Glenn Schneider, Laird Close, Filippo Mannucci, Simone Esposito, Carmelo Arcidiacono, Enrico Pinna, Javier Argomedo, Guido Agapito, Daniel Apai, Giuseppe Bono, Kostantina Boutsia, Runa Briguglio, Guido Brusa, Lorenzo Busoni, Giovanni Cresci, Thayne Currie, Silvano Desidera, Josh Eisner, Renato Falomo, Luca Fini, Kate Follette, Adriano Fontana, Peter Garnavich, Raffaele Gratton, Richard Green, Juan Carlos Guerra, J. M. Hill, William F. Hoffmann, Terry Jay Jones, Megan Krejny, Craig Kulesa, Jared Males, Elena Masciadri, Dino Mesa, Don McCarthy, Michael Meyer, Doug Miller, Matthew J. Nelson, Alfio Puglisi, Fernando Quiros-Pacheco, Armando Riccardi, Eleonora Sani, Paolo Stefanini, Vincenzo Testa, John Wilson, Charles E. Woodward, Marco Xompero

We present diffraction-limited \ks band and \lprime adaptive optics images of the edge-on debris disk around the nearby F2 star HD 15115, obtained with a single 8.4 m primary mirror at the Large Binocular Telescope. At \ks band the disk is detected at signal-to-noise per resolution element (SNRE) \about 3-8 from \about 1-2\fasec 5 (45-113 AU) on the western side, and from \about 1.2-2\fasec 1 (63-90 AU) on the east. At \lprime the disk is detected at SNRE \about 2.5 from \about 1-1\fasec 45 (45-90 AU) on both sides, implying more symmetric disk structure at 3.8 \microns . At both wavelengths the disk has a bow-like shape and is offset from the star to the north by a few AU. A surface brightness asymmetry exists between the two sides of the disk at \ks band, but not at \lprime . The surface brightness at \ks band declines inside 1\asec (\about 45 AU), which may be indicative of a gap in the disk near 1\asec. The \ks - \lprime disk color, after removal of the stellar color, is mostly grey for both sides of the disk. This suggests that scattered light is coming from large dust grains, with 3-10 \microns -sized grains on the east side and 1-10 \microns dust grains on the west. This may suggest that the west side is composed of smaller dust grains than the east side, which would support the interpretation that the disk is being dynamically affected by interactions with the local interstellar medium.

View original: http://arxiv.org/abs/1203.2619