Permalink : http://hdl.handle.net/2115/34713

歳をとった (10^7-10^9年) 星のまわりでは，μmサイズの微小粒子 (デブリ) の円盤 (デブリ円盤) が観測されている．このように星をとった星の周りでは，惑星がすでに形成されている可能性は高い．本研究では，デブリ円盤の内縁に注目して，デブリの昇華によりどのような内縁ができるかを調べた．また，内縁の起源の違いにより位置や形状にどのような起源を持つかを分類した．観測の進歩により，太陽系外の惑星系において昇華リングの観測が可能になり，この昇華によるリングの有無が太陽系外の惑星系での惑星の存在を示すことになるだろう．
In a disk with a low optical depth, dust particles radially drift inward by the Poynting-Robertson (P-R) drag rather than are blown out by stellar radiation pressure following destructive collisions. We investigate the radial distribution of icy dust composed of pure ice and refractory materials in dust-debris disks taking into account the P-R drag and ice sublimation. We find that icy dust particles form a dust ring by their pile-ups at the edge of their sublimation zone, where they sublime substantially at the temperature 100-110K. The distance of the dust ring is 20-35AU from the central star with its luminosity L* ≲ 30L◎ and 65 (L*/100L◎) ^1/2 AU for L* ≳ 30L◎, where L◎ is the solar luminosity. The effective optical depth is enhanced by a factor of 2 for L* ≲ 100L◎ and more than 10 for L* ≳ 100L◎. The optical depth of the outer icy dust disk exceeds that of the inner disk filled with refractory particles, the residue of ice sublimation, which are further subjected to the P-R effect. As a result, an inner hole is formed inside the sublimation zone together with a dust ring along the outer edge of the hole.