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Author Yusef-Zadeh, F. ♦ Royster, M. J. ♦ Roberts, D. A. ♦ Wardle, M. ♦ Cotton, W. ♦ Kunneriath, D. ♦ Schödel, R.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ASYMMETRY ♦ DISTANCE ♦ DUSTS ♦ EMISSION ♦ GALAXIES ♦ GALAXY NUCLEI ♦ GHZ RANGE ♦ IMAGES ♦ MASS TRANSFER ♦ MOLECULES ♦ PROPER MOTION ♦ RESOLUTION ♦ SHELLS ♦ SPECTRA ♦ STARS ♦ STELLAR WINDS
Abstract We present radio and millimeter continuum observations of the Galactic center taken with the Very Large Array (VLA) and ALMA at 44 and 226 GHz, respectively. We detect radio and millimeter emission from IRS 3, lying ∼4.″5 NW of Sgr A*, with a spectrum that is consistent with the photospheric emission from an AGB star at the Galactic center. Millimeter images reveal that the envelope of IRS 3, the brightest and most extended 3.8 μ m Galactic center stellar source, consists of two semicircular dust shells facing the direction of Sgr A*. The outer circumstellar shell, at a distance of 1.6 × 10{sup 4} au, appears to break up into “fingers” of dust directed toward Sgr A*. These features coincide with molecular CS (5–4) emission and a near-IR extinction cloud distributed between IRS 3 and Sgr A*. The NE–SW asymmetric shapes of the IRS 3 shells seen at 3.8 μ m and radio are interpreted as structures that are tidally distorted by Sgr A*. Using the kinematics of CS emission and the proper motion of IRS 3, the tidally distorted outflowing material from the envelope after 5000 yr constrains the distance of IRS 3 to ∼0.7 pc in front of or ∼0.5 pc behind Sgr A*. This suggests that the mass loss by stars near Sgr A* can supply a reservoir of molecular material near Sgr A*. We also present dark features in radio continuum images coincident with the envelope of IRS 3. These dusty stars provide examples in which high-resolution radio continuum images can identify dust-enshrouded stellar sources embedded in an ionized medium.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-03-01
Publisher Place United States
Journal Astrophysical Journal
Volume Number 837
Issue Number 1


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