Reference : New Constraints on Companions and Dust within a Few AU of Vega
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/98689
New Constraints on Companions and Dust within a Few AU of Vega
English
Mennesson, B. mailto [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA]
Serabyn, E. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA]
Hanot, Charles [AEOS, University of Liège, Allée du 6 Août, 17 Bât B5c, 4000 Liège, Belgium]
Martin, Stefan [ > > ]
Liewer, K. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA]
Mawet, D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA]
1-Jul-2011
Astrophysical Journal
University of Chicago Press
736
14
Yes (verified by ORBi)
International
0004-637X
1538-4357
Chicago
IL
[en] circumstellar matter ; instrumentation: high angular resolution ; stars: individual: Vega
[en] We report on high contrast near-infrared (~2.2 μm) observations of Vega obtained with the Palomar Fiber Nuller, a dual sub-aperture rotating coronagraph installed at the Palomar Hale telescope. The data show consistent astrophysical null depth measurements at the ~= 10[SUP]–3[/SUP] level or below for three different baseline orientations spanning 60 deg in azimuth, with individual 1σ uncertainties <=7 × 10[SUP]–4[/SUP]. These high cancellation and accuracy levels translate into a dynamic range greater than 1000:1 inside the diffraction limit of the 5 m telescope beam. Such high contrast performance is unprecedented in the near-infrared and provides improved constraints on Vega's immediate (sime20 to 250 mas, or sime0.15 to 2 AU) environment. In particular, our measurements rule out any potential companion in the [0.25-1 AU] region contributing more than 1% of the overall near-infrared stellar flux, with limits as low as 0.2% near 0.6 AU. These are the best upper limits established so far by direct detection for a companion to Vega in this inner region. We also conclude that any dust population contributing a significant (>=1%) near-infrared thermal excess can arise only within 0.2 AU of the star, and that it must consist of much smaller grains than in the solar zodiacal cloud. Dust emission from farther than sime2 AU is also not ruled out by our observations, but would have to originate in strong scattering, pointing again to very small grains. Based on observations obtained at the Hale Telescope, Palomar Observatory as part of a continuing collaboration between the California Institute of Technology, NASA/JPL, and Cornell University.
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/98689
10.1088/0004-637X/736/1/14
http://adsabs.harvard.edu/abs/2011ApJ...736...14M

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