Artículo de revista
Compact dust concentration in the mwc 758 protoplanetary disk
Fecha
2015Registro en:
Astrophysical Journal Volumen: 813 Número: 1 Nov 2015
DOI: 10.1088/0004-637X/813/1/76
Autor
Marino Estay, Sebastián
Casassus Montero, Simón
Pérez, Sebastián
Lyra, W.
Román, P.
Avenhaus, H.
Wright, C. M.
Maddison, S. T.
Institución
Resumen
The formation of planetesimals requires that primordial dust grains grow from micron- to km-sized bodies.
Dust traps caused by gas pressure maxima have been proposed as regions where grains can concentrate and
grow fast enough to form planetesimals, before radially migrating onto the star. We report new VLA Ka &
Ku observations of the protoplanetary disk around the Herbig Ae/Be star MWC 758. The Ka image shows a
compact emission region in the outer disk indicating a strong concentration of big dust grains. Tracing smaller
grains, archival ALMA data in band 7 continuum shows extended disk emission with an intensity maximum to
the north-west of the central star, which matches the VLA clump position. The compactness of the Ka emission
is expected in the context of dust trapping, as big grains are trapped more easily than smaller grains in gas
pressure maxima. We develop a non-axisymmetric parametric model inspired by a steady state vortex solution
with parameters adequately selected to reproduce the observations, including the spectral energy distribution.
Finally, we compare the radio continuum with SPHERE scattered light data. The ALMA continuum spatially
coincides with a spiral-like feature seen in scattered light, while the VLA clump is offset from the scattered light
maximum. Moreover, the ALMA map shows a decrement that matches a region devoid of scattered polarised
emission. Continuum observations at a different wavelength are necessary to conclude if the VLA-ALMA
difference is an opacity or a real dust segregation.