The dust, planetesimals and planets of HD 38529 - AstrophysicsReport as inadecuate

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Abstract: HD 38529 is a post-main sequence G8III-IV star 3.5 Gyr old with a planetarysystem consisting of at least two planets having Msini of 0.8 MJup and 12.2MJup, semimajor axes of 0.13 AU and 3.74 AU, and eccentricities of 0.25 and0.35, respectively. Spitzer observations show that HD 38529 has an excessemission above the stellar photosphere, with a signal-to-noise ratio S-N at70 micron of 4.7, a small excess at 33 micron S-N=2.6 and no excess <30micron. We discuss the distribution of the potential dust-producingplanetesimals from the study of the dynamical perturbations of the two knownplanets, considering in particular the effect of secular resonances. Weidentify three dynamically stable niches at 0.4-0.8 AU, 20-50 AU and beyond 60AU. We model the spectral energy distribution of HD 38529 to find out which ofthese niches show signs of harboring dust-producing plantesimals. The secularanalysis, together with the SED modeling resuls, suggest that the planetesimalsresponsible for most of the dust emission are likely located within 20-50 AU, aconfiguration that resembles that of the Jovian planets + Kuiper Belt in ourSolar System. Finally, we place upper limits 8E-6 lunar masses of 10 micronparticles to the amount of dust that could be located in the dynamicallystable region that exists between the two planets 0.25-0.75 AU.

Author: Amaya Moro-Martin, Renu Malhotra, John M. Carpenter, Lynne A. Hillenbrand, Sebastian Wolf, Michael R. Meyer, David Hollenbach, Jo


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