Circumstellar molecular line absorption and emission in the optical spectra of post-AGB stars

Autor: Eric J. Bakker, L. B. F. M. Waters, Henny J. G. L. M. Lamers, Ton Schoenmaker
Přispěvatelé: Low Energy Astrophysics (API, FNWI)
Rok vydání: 1995
Předmět:
Zdroj: Astrophysics and Space Science, 224, 335-338. Springer Netherlands
ISSN: 1572-946X
0004-640X
Popis: We present a list of post-AGB stars showing molecular line absorption and emission in the optical spectrum. Two objects show CH+, one in emission and one in absorption, and ten stars show C2 and CN in absorption. The Doppler velocities of the C2 lines and the rotational temperatures indicate that the line forming region is the AGB remnant. An analysis of the post-AGB stars of which CO millimeter data is available suggests that the C2} expansion velocity is of the same order as the CO expansion velocity. HD56126 has been studied in detail and we find a mass-loss rate of Mdot=2.8e-4 Msol/yr, fC2=2.4e-8 and fCN=1.3e-8. The mass loss derived from C2 is significantly larger than Mdot=1.2e-5 Msol/yr derived from CO. We find that all objects with the 21mu feature in emission show C2 and CN absorption, but not all objects with C2 and CN detections show a 21mu feature.
plain latex 8 pages, 4 postscript figures, uses psfig.sty
Databáze: OpenAIRE
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