The latest observation of HL Tau by ALMA revealed spectacular concentric dust rings in its circumstellar disk .
We attempt to explain the multiple ring structure as a consequence of aggregate sintering .
Sintering is known to reduce the sticking efficiency of dust aggregates and occurs at temperatures slightly below the sublimation point of their constituent material .
We here present a dust growth model incorporating sintering and use it to simulate global dust evolution due to sintering , coagulation , fragmentation , and radial inward drift in a modeled HL Tau disk .
We show that aggregates consisting of multiple species of volatile ices experience sintering , collisionally disrupt , and pile up at multiple locations slightly outside the snow lines of the volatiles .
At wavelengths of 0.87–1.3 mm , these sintering zones appear as bright , optically thick rings with a spectral slope of \approx 2 , whereas the non-sintering zones as darker , optically thinner rings of a spectral slope of \approx 2.3 – 2.5 .
The observational features of the sintering and non-sintering zones are consistent with those of the major bright and dark rings found in the HL Tau disk , respectively .
Radial pileup and vertical settling occur simultaneously if disk turbulence is weak and if monomers constituting the aggregates are \sim 1 ~ { } \micron in radius .
For the radial gas temperature profile of T = 310 ( r / 1 ~ { } { AU } ) ^ { -0.57 } ~ { } { K } , our model perfectly reproduces the brightness temperatures of the optically thick bright rings , and reproduces their orbital distances to an accuracy of \lesssim 30 \% .