Neutral carbon in the protoplanetary nebulae CRL 618 and CRL 2688
K Young�- The Astrophysical Journal, 1997 - iopscience.iop.org
K Young
The Astrophysical Journal, 1997•iopscience.iop.orgABSTRACT The 609 μ m $\mathstrut {^{3}} $ P $\mathstrut {_ {1}} $→ $\mathstrut {^{3}} $ P
$\mathstrut {_ {0}} $ line of neutral atomic carbon has been detected in the protoplanetary
nebulae CRL 618 and CRL 2688. CI appears to be about 7% as abundant as CO in CRL
2688 and 70% as abundant as CO in CRL 618. CI emission arises primarily from the slow
component of the wind from these objects. The data presented here indicate that CI
gradually becomes more abundant as the star leaves the asymptotic giant branch and that�…
$\mathstrut {_ {0}} $ line of neutral atomic carbon has been detected in the protoplanetary
nebulae CRL 618 and CRL 2688. CI appears to be about 7% as abundant as CO in CRL
2688 and 70% as abundant as CO in CRL 618. CI emission arises primarily from the slow
component of the wind from these objects. The data presented here indicate that CI
gradually becomes more abundant as the star leaves the asymptotic giant branch and that�…
Abstract
The 609 μ m P → P line of neutral atomic carbon has been detected in the protoplanetary nebulae CRL 618 and CRL 2688. C I appears to be about 7% as abundant as CO in CRL 2688 and 70% as abundant as CO in CRL 618. C I emission arises primarily from the slow component of the wind from these objects. The data presented here indicate that C I gradually becomes more abundant as the star leaves the asymptotic giant branch and that C I is significantly enhanced relative to CO before the star develops a large H II region.
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