Collisional and Thermal Emission Models of Debris Disks: Toward Planetesimal Population Properties

摘要: Debris disks around main-sequence stars are believed to derive from planetesimal populations that have accreted at early epochs and survived possible planet formation processes. While debris must contain solids in a broad range of sizes—from big planetesimals down tiny dust grains—debris disk observations only sensitive the end size distribution. Collisional models needed ‘‘climb up’’ ladder collisional cascade, toward parent bodies, representing main mass reservoir disks. We used our collisionalcodetogeneratefivedisksarounda Sun-likestar,assumingplanetesimalbeltsat3,10,30, 100,and 200 AU with 10 times Edgeworth-Kuiper Belt density, evolve them for Gyr. Along an appropriate scalingrule,thiseffectivelyyieldsathree-parametricsetof referencedisks(initialmass,locationof planetesimalbelt, andage).For allthe disks,wehavegeneratedspectral energydistributions (SEDs),assuming homogeneousspherical astrosilicate grains. A comparison between generated actually observed SEDs yields estimates planetesimalproperties(location,totalmass,etc.).Asatestandafirstapplicationof thisapproach,wehaveselectedfivedisks aroundSun-likestarswithwell-knownSEDs.Infourcases,wehavereproducedthedatawithalinearcombination two grid (an ‘‘asteroid belt’’ 3 outer ‘‘Kuiper Belt’’); one case single, component was sufficient. The components compatible ‘‘large Kuiper Belts’’ 0.2Y50 Earth masses (in bodies up 100 km size) radii 100Y200 AU. Subject headingg circumstellar matter — planetary systems: stars: individual (HD 377, HD 70573, 72905, 107146, 141943)