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Title: The gas-rich disk of HR 4049: A study of the infrared spectrum

Here, we present a summary of our analyses of the mid-and near-infrared spectrum of the unusual evolved binary HR 4049. We f nd that the disk is massive (M > 8 × 10{sup −3} M{sub ⊙}), warm and radially extended. We also report some enrichment in {sup 17}O and {sup 18}O and a comparison of observations from Spitzer-IRS to those obtained by ISO-SWS 10 years earlier reveals that the CO{sub 2} f ux has more than doubled in this time, indicating active and ongoing chemical evolution in the circumbinary disk. Given the high column densities of the gas in the disk, we expect that the molecular gas plays a crucial role in the thermal properties of the circumbinary disk by allowing visible light to heat the dust and then trapping the IR photons emitted by the dust. This will result in higher temperatures and a more homogeneous temperature structure in the disk. Finally, we estimate a mass for the primary in HR 4049 which is too low for the star to have experienced a typical evolutionary path.
Authors:
 [1] ;  [2]
  1. Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)
  2. Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 Canada and SETI Institute, 189 Bernardo Avenue, Suite 100, Mountain View, CA 94034 (United States)
Publication Date:
OSTI Identifier:
22280452
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1594; Journal Issue: 1; Conference: OMEG12: 12. international symposium on origin of matter and evolution of galaxies, Tsukuba (Japan), 18-21 Nov 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BINARY STARS; CARBON DIOXIDE; COMPARATIVE EVALUATIONS; COSMIC DUST; COSMIC PHOTONS; COSMOLOGY; DENSITY; INFRARED SPECTRA; MASS; OXYGEN 17; OXYGEN 18; STAR EVOLUTION; THERMODYNAMIC PROPERTIES; VISIBLE RADIATION