J/A+A/690/A81 Protostellar winds studied with water masers (Moscadelli+, 2024)
Protostellar Outflows at the EarliesT Stages (POETS).
V. The launching mechanism of protostellar winds via water masers.
Moscadelli L., Oliva A., Sanna A., Surcis G., Bayandina O.
<Astron. Astrophys. 690, A81 (2024)>
=2024A&A...690A..81M 2024A&A...690A..81M (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; Masers ; VLBI ; Proper motions
Keywords: masers - techniques: interferometric - stars: formation -
ISM: jets and outflows - ISM: kinematics and dynamics
Abstract:
Understanding the launching mechanism of winds and jets remains one of
the fundamental challenges in astrophysics. The``Protostellar Outflows
at the Earliest Stages'' (POETS) survey has recently mapped the 3D
velocity field of the protostellar winds in a sample (37) of luminous
young stellar objects (YSO) at scales of 10-100au via very long
baseline interferometry (VLBI) observations of the 22GHz water
masers. In most of the targets, the distribution of the 3D maser
velocities can be explained in terms of a magnetohydrodynamic (MHD)
disk-wind (DW). We have performed multi-epoch Very Long Baseline Array
(VLBA) observations of the 22GHz water masers in the YSO
IRAS 21078+5211, the most promising MHD DW candidate from the POETS
survey, to determine the 3D velocities of the gas flowing along
several wind streamlines previously identified at a linear resolution
of ∼1au. By exploiting the 3D kinematic information of the masers, the
launch radii of the streamlines are determined with an accuracy of
∼1au and lie in the range of 10-50au. At increasing larger distances
along the jet, the outflowing gas speeds up while it collimates close
to the jet axis. Magneto-centrifugal launching in a radially extended
MHD DW appears the only viable process to explain the fast (up to
60∼km/s) and collimated (down to 10 deg) velocities of the wind in
correspondence of launch radii ranging between 10 and 50au. The
results obtained in IRAS 21078+5211 demonstrate that VLBI observations
of the 22GHz water masers can reliably determine the launching
mechanism of protostellar winds.
Description:
Four epochs of Very Long Baseline Array (VLBA) observations of the
22GHz water masers in the protostar IRAS 21078+5211. Maser
intensities, positions, LSR velocities, and proper motions are
derived.
Objects:
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RA (2000) DE Designation(s)
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21 09 31.02 +52 24 16.1 IRAS 21078+5211 = [ABB2014] WISE G092.707+03.072
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 335 Water maser parameters
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See also:
J/A+A/631/A74 : POETS luminous YSOs 13 or 22GHz images (Moscadelli+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Maser [0/732] Maser label number
5- 11 A7 --- Epoch Detection epochs (1)
13- 18 F6.3 Jy/beam Int Peak Intensity at 22GHz
20- 24 F5.1 km/s Vlsr LSR velocity
26- 31 F6.2 mas oRA East Offset (2)
33- 36 F4.2 mas e_oRA Error on East Offset
38- 44 F7.2 mas oDE North Offset (2)
46- 49 F4.2 mas e_oDE Error on North Offset
51- 55 F5.1 km/s pmRA ? East Velocity (2)
57- 59 F3.1 km/s e_pmRA ? Error on East Velocity
61- 65 F5.1 km/s pmDE ? North Velocity (2)
67- 69 F3.1 km/s e_pmDE ? Error on North Velocity
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Note (1): The four VLBA epochs are as follows:
1 = March 6, 2023
2 = June 5, 2023
3 = August 5, 2023
4 = October 19, 2023
Note (2): Position offsets and velocities are calculated with respect to
the feature #0. The absolute position of the feature #0 at the first epoch
on March 6, 2023, is: RA, DE = 21:09:21.70580, 52:22:36.9458 (J2000)
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Acknowledgements:
Luca Moscadelli, luca.moscadelli(at)inaf.it
References:
Sanna et al., Paper I 2018A&A...619A.107S 2018A&A...619A.107S
Sanna et al., Paper II 2019A&A...623L...3S 2019A&A...623L...3S
Moscadelli et al., Paper III 2019A&A...631A..74M 2019A&A...631A..74M, Cat. J/A+A/631/A74
Moscadelli et al., Paper IV 2020A&A...635A.118M 2020A&A...635A.118M
(End) Patricia Vannier [CDS] 20-Aug-2024