TY - JOUR
T1 - [Fe II] jets from intermediate-mass protostars in Carina
AU - Reiter, Megan
AU - Smith, Nathan
AU - Bally, John
N1 - Funding Information:
We thank the referee for a thorough and thoughtful report. MR would like to thank Joan Najita and Jaehan Bae for helpful discussions. 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 DataArchive 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 Author(s).
PY - 2016/12/21
Y1 - 2016/12/21
N2 - We present new HST/WFC3-IR narrow-band [Fe II] images of protostellar jets in the Carina Nebula. Combined with five previously published sources, we have a sample of 18 jets and two Herbig-Haro (HH) objects. All of the jets we targeted withWide-Field Camera 3 (WFC3) show bright infrared [Fe II] emission, and a few Hα candidate jets are confirmed as collimated outflows based on the morphology of their [Fe II] emission. Continuum-subtracted images clearly separate jet emission from the adjacent ionization front, providing a better tracer of the collimated jet than Hα and allowing us to connect these jets with their embedded driving sources. The [Fe II] 1.64 μm/Hα flux ratio measured in the jets is ≲5 times larger than in the adjacent ionization fronts. The low-ionization jet core requires high densities to shield Fe+ against further ionization by the FUV radiation from O-type stars in the HII region. High jet densities imply high mass-loss rates, consistent with the intermediate-mass driving sources we identify for 13 jets. The remaining jets emerge from opaque globules that obscure emission from the protostar. In many respects, the HH jets in Carina look like a scaled-up version of the jets driven by low-mass protostars. Altogether, these observations suggest that [Fe II] emission is a reliable tracer of dense, irradiated jets driven by intermediate-mass protostars. We argue that highly collimated outflows are common to more massive protostars, and that they suggest the outflow physics inferred for low-mass stars formation scales up to at least ~8 M⊙.
AB - We present new HST/WFC3-IR narrow-band [Fe II] images of protostellar jets in the Carina Nebula. Combined with five previously published sources, we have a sample of 18 jets and two Herbig-Haro (HH) objects. All of the jets we targeted withWide-Field Camera 3 (WFC3) show bright infrared [Fe II] emission, and a few Hα candidate jets are confirmed as collimated outflows based on the morphology of their [Fe II] emission. Continuum-subtracted images clearly separate jet emission from the adjacent ionization front, providing a better tracer of the collimated jet than Hα and allowing us to connect these jets with their embedded driving sources. The [Fe II] 1.64 μm/Hα flux ratio measured in the jets is ≲5 times larger than in the adjacent ionization fronts. The low-ionization jet core requires high densities to shield Fe+ against further ionization by the FUV radiation from O-type stars in the HII region. High jet densities imply high mass-loss rates, consistent with the intermediate-mass driving sources we identify for 13 jets. The remaining jets emerge from opaque globules that obscure emission from the protostar. In many respects, the HH jets in Carina look like a scaled-up version of the jets driven by low-mass protostars. Altogether, these observations suggest that [Fe II] emission is a reliable tracer of dense, irradiated jets driven by intermediate-mass protostars. We argue that highly collimated outflows are common to more massive protostars, and that they suggest the outflow physics inferred for low-mass stars formation scales up to at least ~8 M⊙.
KW - Formation
KW - Stars
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U2 - 10.1093/mnras/stw2296
DO - 10.1093/mnras/stw2296
M3 - Article
AN - SCOPUS:85020843258
SN - 0035-8711
VL - 463
SP - 4344
EP - 4365
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -