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Title: DEPLETION OF MOLECULAR GAS BY AN ACCRETION OUTBURST IN A PROTOPLANETARY DISK

We investigate new and archival 3-5 μm high-resolution (∼3 km s{sup –1}) spectroscopy of molecular gas in the inner disk of the young solar-mass star EX Lupi, taken during and after the strong accretion outburst of 2008. The data were obtained using the CRIRES spectrometer at the European Southern Observatory Very Large Telescope in 2008 and 2014. In 2008, emission lines from CO, H{sub 2}O, and OH were detected with broad profiles tracing gas near and within the corotation radius (0.02-0.3 AU). In 2014, the spectra display marked differences. The CO lines, while still detected, are much weaker, and the H{sub 2}O and OH lines have disappeared altogether. At 3 μm a veiled stellar photospheric spectrum is observed. Our analysis finds that the molecular gas mass in the inner disk has decreased by an order of magnitude since the outburst, matching a similar decrease in the accretion rate onto the star. We discuss these findings in the context of a rapid depletion of material accumulated beyond the disk corotation radius during quiescent periods, as proposed by models of episodic accretion in EXor-type young stars.
Authors:
; ;  [1] ;  [2] ;  [3]
  1. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  2. Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstr. 1, D-85748 Garching bei München (Germany)
  3. ETH Zürich, Institut für Astronomie, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich (Switzerland)
Publication Date:
OSTI Identifier:
22364740
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 798; 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; ACCRETION DISKS; CARBON MONOXIDE; EMISSION SPECTROSCOPY; MASS; PROTOPLANETS; RESOLUTION; STAR MODELS; STARS; TELESCOPES; WATER