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Image of Fomalhaut dust ring at 350 microns : the relative column density map shows pericenter-apocenter asymmetry

Show simple item record Marsh, K. A. Velusamy, T. Dowell, C. D. Grogan, K. Beichman, C. A. 2007-07-02T22:39:45Z 2007-07-02T22:39:45Z 2005-01-12
dc.identifier.citation The Astrophysical Journal Letters, 620, L47–L50, February 10, 2005 en
dc.identifier.clearanceno 05-0044
dc.description.abstract We have imaged the circumstellar disk of Fomalhaut at 350 mm wavelength, using SHARC II (Submillimeter High Angular Resolution Camera II) at the Caltech Submillimeter Observatory. The spatial resolution of the raw images (9") has been enhanced by a factor of 3 using the HiRes deconvolution procedure. We find that at this wavelength and signal-to-noise ratio (~12), the observed morphology is that of a simple inclined ring (i <about equal>70˚), with little or no other apparent structure—this is the first observation that shows clearly the ring morphology of the disk. We have combined our 350 mm data with Spitzer Space Telescope images at 24, 70, and 160 mm in order to estimate the two-dimensional spatial variation of relative column density (“tau map”) using our DISKFIT procedure. The tau map is based on the following physical assumptions: (1) the wavelength variation of opacity is the same throughout the disk, (2) the radial variation of dust temperature is dictated by the energy balance of individual grains in the stellar radiation field, and (3) the vertical scale height of the disk follows a power-law radial variation. The results confirm the ringlike morphology but also show that the geometric center is displaced from the star by about 8 AU and that the ring has an apocentric enhancement of approximately 14% in integrated column density. If we interpret the displacement in terms of elliptical orbital motion due to gravitational perturbation by an unseen planet, then the implied forced eccentricity is ~0.06; dynamical modeling then predicts an apocentric density enhancement consistent with that inferred from the tau map. en
dc.description.sponsorship NASA/JPL en
dc.format.extent 111613 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US en
dc.publisher The American Astronomical Society en
dc.subject circumstellar matter en
dc.subject planetary systems en
dc.subject Fomalhaut en
dc.subject stars en
dc.title Image of Fomalhaut dust ring at 350 microns : the relative column density map shows pericenter-apocenter asymmetry en
dc.type Article en

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