2015/10/31 by Satoshi Okuzumi, Munetake Momose, Sin-iti Sirono +2 · 304 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Cosmic dust #Millimeter #Settling #Sintering #Spectral slope #Stellar, planetary, and galactic studies #Sublimation (psychology) #Turbulence #Wavelength #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/0004-637x/821/2/82
published in The Astrophysical Journal 821(2), 82 (IOP Publishing) · 24 pages, 20 figures, discussion section added, accepted for publication in ApJ
arxiv created 2016/02/03 · openalex publication_date 2016/04/13 · arxiv updated 2016/04/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
ABSTRACT 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 the constituent material. We present a dust growth model that incorporates 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≈</mml:mo> <mml:mn>2</mml:mn> </mml:math> , whereas the non-sintering zones appear as darker, optically thinner rings of a spectral slope of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≈</mml:mo> <mml:mn>2.3</mml:mn> </mml:math> –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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>1</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>μ</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:math> in radius. For the radial gas temperature profile of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>T</mml:mi> <mml:mo>=</mml:mo> <mml:mn>310</mml:mn> <mml:msup> <mml:mrow> <mml:mo stretchy="true">(</mml:mo> <mml:mi>r</mml:mi> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mn>1</mml:mn> <mml:mspace width="0.25em"/> <mml:mi>au</mml:mi> <mml:mo stretchy="true">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.57</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">K</mml:mi> </mml:math> , our model perfectly reproduces the brightness temperatures of the optically thick bright rings and reproduces their orbital distances to an accuracy of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>≲</mml:mo> <mml:mn>30</mml:mn> <mml:mo>%</mml:mo> </mml:math> .