Discovery of an 86 AU Radius Debris Ring around HD 181327

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dc.contributor.author Silverstone, Murray
dc.date.accessioned 2019-06-13T17:58:37Z
dc.date.available 2019-06-13T17:58:37Z
dc.date.issued 2006
dc.identifier.citation Schneider, G., et al. (2006): Discovery of an 86 AU Radius Debris Ring around HD 181327. The Astronomical Journal, 650(1): https://doi.org/10.1086/506507 en_US
dc.identifier.uri http://ir.ua.edu/handle/123456789/5744
dc.description.abstract HST NICMOS PSF-subtracted coronagraphic observations of HD 181327 have revealed the presence of a ringlike disk of circumstellar debris seen in 1.1 μm light scattered by the disk grains, surrounded by a diffuse outer region of lower surface brightness. The annular disk appears to be inclined by 31 7 ± 1fdg6 from face-on, with the disk major-axis P.A. at 107° ± 2°. The total 1.1 μm flux density of the light scattered by the disk (at 1 2 < r < 5 0) of 9.6 ± 0.8 mJy is 0.17% ± 0.015% of the starlight. Seventy percent of the light from the scattering grains appears to be confined in a 36 AU wide annulus centered on the peak of the radial surface brightness (SB) profile 86.3 ± 3.9 AU from the star, well beyond the characteristic radius of thermal emission estimated from IRAS and Spitzer flux densities, assuming blackbody grains (≈22 AU). The 1.1 μm light scattered by the ring (1) appears bilaterally symmetric, (2) exhibits directionally preferential scattering well represented by a Henyey-Greenstein scattering phase function with gHG = 0.30 ± 0.03, and (3) has a median SB (over all azimuth angles) at the 86.3 AU radius of peak SB of 1.00 ± 0.07 mJy arcsec⁻². No photocentric offset is seen in the ring relative to the position of the central star. A low SB diffuse halo is seen in the NICMOS image to a distance of ~4''. Deeper 0.6 μm Hubble Space Telescope (HST) ACS PSF-subtracted coronagraphic observations reveal a faint (V ≈ 21.5 mag arcsec⁻²) outer nebulosity at 4'' < r < 9'', asymmetrically brighter to the north of the star. We discuss models of the disk and properties of its grains, from which we infer a maximum vertical scale height of 4-8 AU at the 87.6 AU radius of maximum surface density, and a total maximum dust mass of collisionally replenished grains with minimum grain sizes of ≈1 μm of ≈4MMoon. en_US
dc.format.mimetype application/pdf en_US
dc.language English en_US
dc.subject circumstellar matter en_US
dc.subject infrared: stars en_US
dc.subject planetary systems: protoplanetary disks en_US
dc.subject stars: individual (HD 181327) en_US
dc.title Discovery of an 86 AU Radius Debris Ring around HD 181327 en_US
dc.type text en_US


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