The inner gaseous accretion disk around a Herbig Be star revealed by near- and mid-infrared spectro-interferometry

S. Kraus, Th Preibisch, K. Ohnaka

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Abstract Herbig Ae/Be stars are pre-main-sequence stars of intermediate mass, which are still accreting material from their environment, probably via a disk composed of gas and dust. Here we present a recent study of the geometry of the inner (AU-scale) circumstellar region around the Herbig Be star MWC 147 using long-baseline interferometry. By combining for the first time near- and mid-infrared spectro-interferometry on a Herbig star, our VLTI/AMBER and VLTI/MIDI data constrain not only the geometry of the brightness distribution, but also the radial temperature distribution in the disk. The emission from MWC 147 is clearly resolved and has a characteristic physical size of 1.3 AU and 9 AU at 2.2 m and 11 m respectively. This increase in apparent size towards longer wavelengths is much steeper than predicted by analytic disk models assuming power-law radial temperature distributions. For a detailed modeling of the interferometric data and the spectral energy distribution of MWC 147, we employ 2-D frequency-dependent radiation transfer simulations. This analysis shows that passive irradiated Keplerian dust disks can easily fit the SED, but predict much lower visibilities than observed, so these models can clearly be ruled out. Models of a Keplerian disk with emission from an optically thick inner gaseous accretion disk (inside the dust sublimation zone), however, yield a good fit of the SED and simultaneously reproduce the observed near- and mid-infrared visibilities. We conclude that the near-infrared continuum emission from MWC 147 is dominated by accretion luminosity emerging from an optically thick inner gaseous disk, while the mid-infrared emission also contains strong contributions from the passive irradiated dust disk.

Original languageEnglish
Pages (from-to)337-344
Number of pages8
JournalProceedings of the International Astronomical Union
Volume3
Issue number1 S243
DOIs
Publication statusPublished - Aug 2007
Externally publishedYes

Keywords

  • Accretion
  • Accretion disks
  • Individual (MWC 147)
  • Premain-sequence
  • Radiative transfer
  • Stars: formation
  • Techniques: interferometric

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science

Fingerprint

Dive into the research topics of 'The inner gaseous accretion disk around a Herbig Be star revealed by near- and mid-infrared spectro-interferometry'. Together they form a unique fingerprint.

Cite this