SPECTRO-INTERFEROMETRY OF THE Be STAR {delta} Sco: NEAR-INFRARED CONTINUUM AND GAS EMISSION REGION SIZES IN 2007

Journal Article · Mon Nov 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/1/544· OSTI ID:21467184

Millan-Gabet, R ^[1]; Monnier, J D ^[2]; Touhami, Y; Gies, D ^[3]; Hesselbach, E ^[4]; Pedretti, E; Thureau, N ^[5]; Zhao, M ^[6]

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1. California Institute of Technology, NASA Exoplanet Science Institute, Pasadena, CA 91125 (United States)
2. Department of Astronomy, University of Michigan, MI 48109 (United States)
3. Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302 (United States)
4. Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
5. School of Physics and Astronomy University of St. Andrews, St. Andrews, Fife, KY16 9SS (United Kingdom)
6. Jet Propulsion Laboratory, 4800 Oak Grove Drive, M.S. 169-327, Pasadena, CA 91101 (United States)

We present near-infrared H- and K-band spectro-interferometric observations of the gaseous disk around the primary Be star in the {delta} Sco binary system, obtained in 2007 (between periastron passages in 2000 and 2011). Observations using the CHARA/MIRC instrument at H band resolve an elongated disk with a Gaussian FWHM 1.18 x 0.91 mas. Using the Keck Interferometer (KI), the source of the K-band continuum emission is only marginally spatially resolved, and consequently we estimate a relatively uncertain K-band continuum disk FWHM of 0.7 {+-} 0.3 mas. Line emission on the other hand, He I {lambda}2.0583 {mu}m and Br{gamma} {lambda}2.1657 {mu}m, is clearly detected, with {approx}10% lower visibilities than those of the continuum. When taking into account the continuum/line flux ratio this translates into much larger sizes for the line emission regions: 2.2 {+-} 0.4 mas and 1.9 {+-} 0.3 mas for He I and Br{gamma}, respectively. Our KI data also reveal a relatively flat spectral differential phase response, ruling out significant off-center emission. We expect that these new measurements will help constrain dynamical models being actively developed in order to explain the disk formation process in the {delta} Sco system and Be stars in general.

• OSTI ID: 21467184
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 723; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
EMISSION
INTERFEROMETERS
INTERFEROMETRY
MEASURING INSTRUMENTS
RESOLUTION
STARS