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Title: TRANSITION DISK CHEMISTRY AND FUTURE PROSPECTS WITH ALMA

Journal Article · · Astrophysical Journal Letters
; ; ; ;  [1]; ;  [2]
  1. Department of Astronomy, University of Michigan, 825 Dennison Building, 500 Church St, Ann Arbor, MI 48109 (United States)
  2. Christian-Albrechts-Universitaet zu Kiel, Institut fuer Theoretische Physik und Astrophysik, Leibnizstr. 15, 24098 Kiel (Germany)

We explore the chemical structure of a disk that contains a large central gap of R {approx} 45 AU, as is commonly seen in transitional disk systems. In our chemical model of a disk with a cleared inner void, the midplane becomes revealed to the central star so that it is directly irradiated. The midplane material at the truncation radius is permissive to reprocessed optical heating radiation, but opaque to the photodissociating ultraviolet, creating an environment abundant in gas-phase molecules. Thus the disk midplane, which would otherwise for a full disk be dominated by near complete heavy element freeze-out, should become observable in molecular emission. If this prediction is correct this has exciting prospects for observations with the Atacama Large Millimeter/Submillimeter Array, as the inner transition region should thus be readily detected and resolved, especially using high-J rotational transitions excited in the high density midplane gas. Therefore, such observations will potentially provide us with a direct probe of the physics and chemistry at this actively evolving interface.

OSTI ID:
22047317
Journal Information:
Astrophysical Journal Letters, Vol. 743, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
Country of Publication:
United States
Language:
English