The 0.5-2.22 μm scattered light spectrum of the disk around TW HYA: Detection of a partially filled disk GAP at 80 AU

John H. Debes, Hannah Jang-Condell, Alycia J. Weinberger, Aki Roberge, Glenn Schneider

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86 Scopus citations


We present a 0.5-2.2 μm scattered light spectrum of the circumstellar disk around TW Hya from a combination of spatially resolved Hubble Space Telescope STIS spectroscopy and NICMOS coronagraphic images of the disk. We investigate the morphology of the disk at distances >40 AU over this wide range of wavelengths, and identify the presence of a depression in surface brightness at ∼80 AU that could be caused by a gap in the disk. Additionally, we quantify the surface brightness, azimuthal symmetry, and spectral character of the disk as a function of radius. Our analysis shows that the scattering efficiency of the dust is largely neutral to blue over the observed wavelengths. We model the disk as a steady α-disk with an ad hoc gap structure. The thermal properties of the disk are self-consistently calculated using a three-dimensional radiative transfer code that uses ray tracing to model the heating of the disk interior and scattered light images. We find a good fit to the data over a wide range of distances from the star if we use a model disk with a partially filled gap of 30% depth at 80 AU and with a self-similar truncation knee at 100 AU. The origin of the gap is unclear, but it could arise from a transition in the nature of the disk's dust composition or the presence of a planetary companion. Based on scalings to previous hydrodynamic simulations of gap-opening criteria for embedded proto-planets, we estimate that a planetary companion forming the gap could have a mass between 6 and 28 M.

Original languageEnglish (US)
Article number45
JournalAstrophysical Journal
Issue number1
StatePublished - Jul 1 2013


  • disk interactions
  • planet
  • protoplanetary disks
  • radiative transfer
  • stars: individual (TW Hya)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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