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Title: A combined Spitzer and Herschel infrared study of gas and dust in the circumbinary disk orbiting V4046 Sgr

Journal Article · · Astrophysical Journal
; ;  [1];  [2]; ; ;  [3];  [4]
  1. School of Physics and Astronomy, Rochester Institute of Technology, 1 Lomb Memorial Drive, Rochester, NY 14623-5603 (United States)
  2. INAF-Arcetri Astrophysical Observatory, Largo Enrico Fermi 5, I-50125 Florence (Italy)
  3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  4. Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871 (China)

We present results from a spectroscopic Spitzer and Herschel mid-to-far-infrared study of the circumbinary disk orbiting the evolved (age ∼12–23 Myr) close binary T Tauri system V4046 Sgr. Spitzer InfraRed Spectrograph spectra show emission lines of [Ne ii], H{sub 2} S(1), CO{sub 2}, and HCN, while Herschel Photodetector Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver spectra reveal emission from [O i], OH, and tentative detections of H{sub 2}O and high-J transitions of CO. We measure [Ne iii]/[Ne ii] ≲ 0.13, which is comparable to other X-ray/EUV luminous T Tauri stars that lack jets. We use the H{sub 2} S(1) line luminosity to estimate the gas mass in the relatively warm surface layers of the inner disk. The presence of [O i] emission suggests that CO, H{sub 2}O, and/or OH is being photodissociated, and the lack of [C i] emission suggests any excess C may be locked up in HCN, CN, and other organic molecules. Modeling of silicate dust grain emission features in the mid-infrared indicates that the inner disk is composed mainly of large (r ∼ 5 μm) amorphous pyroxene and olivine grains (∼86% by mass) with a relatively large proportion of crystalline silicates. These results are consistent with other lines of evidence indicating that planet building is ongoing in regions of the disk within ∼30 AU of the central, close binary.

OSTI ID:
22882713
Journal Information:
Astrophysical Journal, Vol. 810, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
Country of Publication:
United Kingdom
Language:
English