TY - JOUR
T1 - Proper motions of collimated jets from intermediate-mass protostars in the Carina Nebula
AU - Reiter, Megan
AU - Kiminki, Megan M.
AU - Smith, Nathan
AU - Bally, John
N1 - Funding Information:
Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. We are grateful to the University of Arizona Observatory time assignment committee who awarded time to this programme, and thank the MMT telescope operators and staff for technical support. We are indebted to Alis Deason for providing the first-look spectroscopic observations of a subset of our sample that were used to support our initial MMT proposal. It is a pleasure to acknowledge Rob Kennicutt for useful discussions concerning dwarf galaxy populations, Matt Auger who helped with various aspects of the data analysis, and Evan Skillman for insightful comments on an early version of this work. We sincerely thank the reviewer of the paper, Jorge Sanchez Almeida, whose helpful comments and suggestions greatly improved the paper. EWO is partially supported by NSF grant AST1313006. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 308024. SK acknowledges financial support from the ERC. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Funding Information:
Institution. We are grateful to the University of Arizona Observatory time assignment committee who awarded time to this programme, and thank the MMT telescope operators and staff for technical support. We are indebted to Alis Deason for providing the first-look spectroscopic observations of a subset of our sample that were used to support our initial MMT proposal. It is a pleasure to acknowledge Rob Kennicutt for useful discussions concerning dwarf galaxy populations, Matt Auger who helped with various aspects of the data analysis, and Evan Skillman for insightful comments on an early version of this work. We sincerely thank the reviewer of the paper, Jorge Sanchez Almeida, whose helpful comments and suggestions greatly improved the paper. EWO is partially supported by NSF grant AST1313006. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 308024. SK acknowledges financial support from the ERC. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Publisher Copyright:
© 2017 The Authors.
PY - 2017/10
Y1 - 2017/10
N2 - We present proper motion measurements of 37 jets and HH objects in the Carina Nebula measured in two epochs of Hα images obtained ~10 yr apart with Hubble Space Telescope/ Advanced Camera for Surveys (ACS). Transverse velocities in all but one jet are faster than ≳ 25 km s-1, confirming that the jet-like Hα features identified in the first epoch images trace outflowing gas. Proper motions constrain the location of the jet-driving source and provide kinematic confirmation of the intermediate-mass protostars that we identify for 20/37 jets. Jet velocities do not correlate with the estimated protostar mass and embedded driving sources do not have slower jets. Instead, transverse velocities (median ~75 km s-1) are similar to those in jets from low-mass stars. Assuming a constant velocity since launch, we compute jet dynamical ages (median ~104 yr). If continuous emission from inner jets traces the duration of the most recent accretion bursts, then these episodes are sustained longer (median ~700 yr) than the typical decay time of an FU Orionis outburst. These jets can carry appreciable momentum that may be injected into the surrounding environment. The resulting outflow force, dP/dt, lies between that measured in low- and high-mass sources, despite the very different observational tracers used. Smooth scaling of the outflow force argues for a common physical process underlying outflows from protostars of all masses. This latest kinematic result adds to a growing body of evidence that intermediate-mass star formation proceeds like a scaled-up version of the formation of low-mass stars.
AB - We present proper motion measurements of 37 jets and HH objects in the Carina Nebula measured in two epochs of Hα images obtained ~10 yr apart with Hubble Space Telescope/ Advanced Camera for Surveys (ACS). Transverse velocities in all but one jet are faster than ≳ 25 km s-1, confirming that the jet-like Hα features identified in the first epoch images trace outflowing gas. Proper motions constrain the location of the jet-driving source and provide kinematic confirmation of the intermediate-mass protostars that we identify for 20/37 jets. Jet velocities do not correlate with the estimated protostar mass and embedded driving sources do not have slower jets. Instead, transverse velocities (median ~75 km s-1) are similar to those in jets from low-mass stars. Assuming a constant velocity since launch, we compute jet dynamical ages (median ~104 yr). If continuous emission from inner jets traces the duration of the most recent accretion bursts, then these episodes are sustained longer (median ~700 yr) than the typical decay time of an FU Orionis outburst. These jets can carry appreciable momentum that may be injected into the surrounding environment. The resulting outflow force, dP/dt, lies between that measured in low- and high-mass sources, despite the very different observational tracers used. Smooth scaling of the outflow force argues for a common physical process underlying outflows from protostars of all masses. This latest kinematic result adds to a growing body of evidence that intermediate-mass star formation proceeds like a scaled-up version of the formation of low-mass stars.
KW - Haro objects
KW - ISM: jets and outflows
KW - ISM: kinematics and dynamics
KW - Stars: formation -Herbig
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U2 - 10.1093/MNRAS/STX1489
DO - 10.1093/MNRAS/STX1489
M3 - Article
AN - SCOPUS:85046103383
SN - 0035-8711
VL - 470
SP - 4671
EP - 4697
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -