Associations of H2O and CH3OH masers at milli-arcsec angular resolution in two high-mass YSOs

作者：Goddi C^*; Moscadelli L; Sanna A; Cesaroni R; Minier V

来源：Astronomy & Astrophysics, 2007, 461(3): 1027-1035.

DOI：10.1051/0004-6361:20066136

• masers
• stars : circumstellar matter
• ISM : kinematics and dynamics
• ISM : jets and outflows
• radio lines : stars

Context. While high-angular resolution observations have clarified that water masers originate from shocks associated with protostellar jets, different environments have been proposed in several sources to explain the origin of CH3OH masers.
Aims. We wish to investigate the nature of the CH3OH maser birthplace in SFRs and the association between the H2O and CH3OH maser emission in the same YSO.
Methods. We have conducted phase-reference VLBI observations of H2O and CH3OH masers toward two high-mass SFRs, Sh 2-255 IR and AFGL 5142.
Results. In Sh 2-255 IR water masers are aligned along a direction close to the orientation of the molecular outflow observed on angular scales of 1 - 10 arcsec, tracing possibly the disk-wind emerging from the disk atmosphere. In AFGL 5142 water masers trace expansion at the base of a protostellar jet, whilst methanol masers are more probably tracing infalling than outflowing gas.
Conclusions. The results for AFGL 5142 suggest that water and methanol masers trace different kinematic structures in the circumstellar gas.

• 出版日期2007-1
• 单位中国地震局