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.
Original language | English |
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Pages (from-to) | L77-L80 |
Number of pages | 4 |
Journal | The Astrophysical Journal |
Volume | 645 |
Issue number | 1 |
Publication status | Published - 1 Jul 2006 |