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Published July 1, 2006 | Published
Journal Article Open

Bright localized near-infrared emission at 1-4 AU in the AB Aurigae disk revealed by IOTA closure phases

Abstract

We report on the detection of localized off-center emission at 1-4 AU in the circumstellar environment of the young stellar object AB Aurigae. We used closure-phase measurements in the near-infrared that were made at the long-baseline interferometer IOTA, the first obtained on a young stellar object using this technique. When probing sub-AU scales, all closure phases are close to zero degrees, as expected given the previously determined size of the AB Aurigae inner-dust disk. However, a clear closure-phase signal of -3.5d +/- 0.5d is detected on one triangle containing relatively short baselines, requiring a high degree of non-point symmetry from emission at larger (AU-sized) scales in the disk. We have not identified any alternative explanation for these closure-phase results, and we demonstrate that a "disk hot spot" model can fit our data. We speculate that such detected asymmetric near-infrared emission might arise as a result of localized viscous heating due to a gravitational instability in the AB Aurigae disk, or to the presence of a close stellar companion or accreting substellar object.

Additional Information

© 2006 The American Astronomical Society. Received 2006 May 1; accepted 2006 May 23; published 2006 June 28. The authors gratefully acknowledge support from SAO, NASA (for third telescope development and NNG05G1180G), the NSF (AST-0138303, AST-0352723, for work on imaging with IOTA), and the Jet Propulsion Laboratory (JPL awards 1236050 and 1248252). The IONIC-3 instrument has been developed by LAOG and LETI in the context of the IONIC collaboration (LAOG, IMEP, LETI). The IONIC project is funded by the CNRS (France) and CNES (France).

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August 22, 2023
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October 16, 2023