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:
We wish to thank Jay Anderson for helping us quantify the additional uncertainty introduced by the 180° rotation between epochs. Thanks also to Bo Reipurth for helpful conversations. MR would like to thank John Bieging, TomHaworth andChris Miller.HHnumbers are assigned by Bo Reipurth in order to correspond with the catalogue of HH objects maintained at http://ifa.hawaii.edu/reipurth/; see also Reipurth & Reiter (2017), A General Catalog of Herbig-Haro Objects, 3rd Edition, in preparation. Support for this work was provided by NASA through grants AR-12155, GO-13390 and GO-13391 from the Space Telescope Science Institute. This work is based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These HST observations are associated with programmes GO 10241, 10475, 13390 and 13391.
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
VL - 470
SP - 4671
EP - 4697
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -