Volume 549, January 2013
|Number of page(s)||5|
|Section||Interstellar and circumstellar matter|
|Published online||15 January 2013|
A close-up view of a bipolar jet: Sub-arcsecond near-infrared imaging of the high-mass protostar IRAS 20126+4104⋆
1 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze Italy
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2 INAF, Osservatorio Astronomico di Bologna, Via Ranzani 1, 40127 Bologna, Italy
3 Steward Observatory, The University of Arizona, 933 N. Cherry Ave., Tucson, AZ-85721, USA
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4 INAF, Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio, Italy
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Received: 22 October 2012
Accepted: 14 November 2012
Context. The formation of OB-type stars up to (at least) 140 M⊙ can be explained via disk-mediated accretion and in fact growing observational evidence of disk-jet systems is found in high-mass star-forming regions.
Aims. With the present observations we wish to investigate at sub-arcsecond resolution the jet structure close to the well studied high-mass protostar IRAS 20126+4104, which is known to be surrounded by a Keplerian disk.
Methods. Adaptive optics imaging of the 2.2 μm continuum and H2 and Brγ line emission have been performed with the Large Binocular Telescope, attaining an angular resolution of ~90 mas and an astrometric precision of ~100 mas.
Results. While our results are consistent with previous K-band images by other authors, the improved (by a factor ~3) resolution allows us to identify a number of previously unseen features, such as bow shocks spread all over the jet structure. Also, we confirm the existence of a bipolar nebulosity within 1′′ from the protostar, prove that the emission from the brightest, SE lobe is mostly due to the H2 line, and resolve its structure.
Conclusions. Comparison with other tracers such as masers, thermal molecular line emission, and free-free continuum emission proves that the bipolar nebulosity is indeed tracing the root of the bipolar jet powered by the deeply embedded protostar at the center of the Keplerian disk.
Key words: stars: formation / ISM: individual objects: IRAS 20126+4104 / ISM: jets and outflows
Based on observations carried out with the Large Binocular Telescope. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.
© ESO, 2013
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