Adaptive optics nulling interferometric constraints on the mid-infrared exozodiacal dust emission around vega

Wilson M. Liu, Philip M. Hinz, William F. Hoffmann, Guido Brusa, Francois Wildi, Doug Miller, Michael Lloyd-Hart, Matthew A. Kenworthy, Patrick C. McGuire, J. R.P. Angel

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

We present the results of mid-infrared nulling interferometric observations of the main-sequence star α Lyr (Vega) using the 6.5 m MMT with its adaptive secondary mirror. From the observations at 10.6 μm, we find that there is no resolved emission from the circumstellar environment (at separations greater than 0.8 AU) above 2.1% (3 σ limit) of the level of the stellar photospheric emission. Thus, we are able to place an upper limit on the density of dust in the inner system of 650 times that of our own solar system's zodiacal cloud. This limit is roughly 2.8 times better than those determined with photometric excess observations such as those by IRAS. Comparison with far-infrared observations by IRAS shows that the density of warm dust in the inner system (<30 AU) is significantly lower than cold dust at larger separations. We consider two scenarios for grain removal, the sublimation of ice grains and the presence of a planetary mass "sweeper." We find that if sublimation of ice grains is the only removal process, a large fraction (>80%) of the material in the outer system is ice.

Original languageEnglish (US)
Pages (from-to)L125-L128
JournalAstrophysical Journal
Volume610
Issue number2 II
DOIs
StatePublished - Aug 1 2004

Keywords

  • Circumstellar matter
  • Instrumentation: adaptive optics
  • Stars: individual (Vega)
  • Techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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