Nimesh A. Patel et al 2009 ApJ 691 L55 doi:10.1088/0004-637X/691/1/L55
Nimesh A. Patel1, Ken H. Young1, Sandra Brünken1,2, Karl M. Menten3, Patrick Thaddeus1 and Robert W. Wilson1
Show affiliationsUsing the Submillimeter Array we have detected the J = 3-2 and 2-1 rotational transitions from within the first vibrationally excited state of CO toward the extreme carbon star IRC+10216 (CW Leo). The emission remains spatially unresolved with an angular resolution of ~2'' and, given that the lines originate from energy levels that are ~3100 K above the ground state, almost certainly originates from a much smaller (~1014 cm) sized region close to the stellar photosphere. Thermal excitation of the lines requires a gas density of ~109 cm–3, about an order of magnitude higher than the expected gas density based on previous infrared observations and models of the inner dust shell of IRC+10216.
circumstellar matter; radio lines: stars; stars: individual (IRC+10216); stars: late-type; submillimeter
95.85.Fm Submillimeter (300 &mgr;m–1 mm)
95.85.Hp Infrared (3–10 &mgr;m)
Issue 1 (2009 January 20)
Received 2008 November 12, accepted for publication 2008 November 26
Published 2009 January 7
Nimesh A. Patel et al 2009 ApJ 691 L55
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