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Astron. Astrophys. 327, 758-770

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L 1287 (H2O): accretion disk-impinging-clumps traced by masers?

D. Fiebig

Institut für Theoretische Astrophysik, Universität Heidelberg, Tiergartenstraße 15, D-69121 Heidelberg, Germany

Received 10 October 1996 / Accepted 1 July 1997


An earlier multi-epoch high angular resolution study of the 22 GHz maser emission from the dark cloud core L 1287 presented an unusual position-velocity distribution of the identified masers. Since the observational results could only unsatisfactorily be modeled in terms of an outflow association, the alternative interpretation of a disk origin is investigated in some more detail. Clumpy mass infall onto the accretion disk around the embedded protostar in L 1287 is identified as the hydrodynamic trigger mechanism for the maser excitation. Shock compressed clump layers are found likely to have the required density, temperature and column density for detectable 22 GHz maser emission. A simplified model of the velocity field in the shocked clump layers leads to a remarkable agreement with the position-velocity distribution of the observed masers.

Key words: accretion disks - masers - shock waves - stars: formation - ISM: kinematics and dynamics - radio lines: ISM - ISM: L 1287

© European Southern Observatory (ESO) 1997

Online publication: October 14, 1997
Last change: April 6, 1998