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Title: Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}

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 ofmore » 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.« less

Authors:
; ;  [1];  [2]; ;  [3];  [4]
  1. Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)
  2. Department of Physics and Astronomy and Research Center for Astronomy, Astrophysics and Astrophotonics, Macquarie University, Sydney NSW 2109 (Australia)
  3. National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)
  4. Instituto de Astfisica de Andalucia (CSIC), Glorieta de la Astronomia S/N, E-18008 Granada (Spain)
Publication Date:
OSTI Identifier:
22661306
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 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

Citation Formats

Yusef-Zadeh, F., Royster, M. J., Roberts, D. A., Wardle, M., Cotton, W., Kunneriath, D., and Schödel, R. Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5EA2.
Yusef-Zadeh, F., Royster, M. J., Roberts, D. A., Wardle, M., Cotton, W., Kunneriath, D., & Schödel, R. Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}. United States. doi:10.3847/1538-4357/AA5EA2.
Yusef-Zadeh, F., Royster, M. J., Roberts, D. A., Wardle, M., Cotton, W., Kunneriath, D., and Schödel, R. Wed . "Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}". United States. doi:10.3847/1538-4357/AA5EA2.
@article{osti_22661306,
title = {Tidal Distortion of the Envelope of an AGB Star IRS 3 near Sgr A{sup *}},
author = {Yusef-Zadeh, F. and Royster, M. J. and Roberts, D. A. and Wardle, M. and Cotton, W. and Kunneriath, D. and Schödel, R.},
abstractNote = {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.},
doi = {10.3847/1538-4357/AA5EA2},
journal = {Astrophysical Journal},
number = 1,
volume = 837,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}