TY - JOUR
T1 - The outflow history of two Herbig-Haro jets in RCW 36
T2 - HH 1042 and HH 1043
AU - Ellerbroek, L. E.
AU - Podio, L.
AU - Kaper, L.
AU - Sana, H.
AU - Huppenkothen, D.
AU - De Koter, A.
AU - Monaco, L.
N1 - Funding Information:
The anonymous referee is acknowledged for useful comments and suggestions that have improved the paper. The authors thank Daniele Malesani, Beate Stelzer and the ESO staff for obtaining some of the spectra. Francesca Bacciotti, Arjan Bik, Sylvie Cabrit, Carsten Dominik, Teresa Giannini, Michiel van der Klis, Lorenzo Maurri, Brunella Nisini, Rens Waters and Hugh Wheelwright are acknowledged for inspiring discussions. L.P. acknowledges the funding from the FP7 Intra-European Marie Curie Fellowship (PIEF-GA-2009-253896).
PY - 2013
Y1 - 2013
N2 - Jets around low-and intermediate-mass young stellar objects (YSOs) contain a fossil record of the recent accretion and outflow activity of their parent star-forming systems. We aim to understand whether the accretion/ejection process is similar across the entire stellar mass range of the parent YSOs. To this end we have obtained optical to near-infrared spectra of HH 1042 and HH 1043, two newly discovered jets in the massive star-forming region RCW 36, using X-shooter on the ESO Very Large Telescope. HH 1042 is associated with the intermediate-mass YSO 08576nr292. Over 90 emission lines are detected in the spectra of both targets. High-velocity (up to 220 km s-1) blue-and redshifted emission from a bipolar flow is observed in typical shock tracers. Low-velocity emission from the background cloud is detected in nebular tracers, including lines from high ionization species. We applied combined optical and infrared spectral diagnostic tools in order to derive the physical conditions (density, temperature, and ionization) in the jets. The measured mass outflow rates are Mjet 10-7M· yr-1. It is not possible to determine a reliable estimate for the accretion rate of the driving source of HH 1043 using optical tracers. We measure a high accretion rate for the driving source of HH 1042 (Macc 10-6M · yr-1). For this system the ratio ájetMacc 0.1, which is comparable to low-mass sources and consistent with models for magneto-centrifugal jet launching. The knotted structure and velocity spread in both jets are interpreted as fossil signatures of a variable outflow rate. While the mean velocities in both lobes of the jets are comparable, the variations in mass outflow rate and velocity in the two lobes are not symmetric. This asymmetry suggests that the launching mechanism on either side of the accretion disk is not synchronized. For the HH 1042 jet, we have constructed an interpretative physical model with a stochastic or periodic outflow rate and a description of a ballistic flow as its constituents. We have simulated the flow and the resulting emission in position-velocity space, which is then compared to the observed kinematic structure. The knotted structure and velocity spread can be reproduced qualitatively with the model. The results of the simulation indicate that the outflow velocity varies on timescales on the order of 100 yr.
AB - Jets around low-and intermediate-mass young stellar objects (YSOs) contain a fossil record of the recent accretion and outflow activity of their parent star-forming systems. We aim to understand whether the accretion/ejection process is similar across the entire stellar mass range of the parent YSOs. To this end we have obtained optical to near-infrared spectra of HH 1042 and HH 1043, two newly discovered jets in the massive star-forming region RCW 36, using X-shooter on the ESO Very Large Telescope. HH 1042 is associated with the intermediate-mass YSO 08576nr292. Over 90 emission lines are detected in the spectra of both targets. High-velocity (up to 220 km s-1) blue-and redshifted emission from a bipolar flow is observed in typical shock tracers. Low-velocity emission from the background cloud is detected in nebular tracers, including lines from high ionization species. We applied combined optical and infrared spectral diagnostic tools in order to derive the physical conditions (density, temperature, and ionization) in the jets. The measured mass outflow rates are Mjet 10-7M· yr-1. It is not possible to determine a reliable estimate for the accretion rate of the driving source of HH 1043 using optical tracers. We measure a high accretion rate for the driving source of HH 1042 (Macc 10-6M · yr-1). For this system the ratio ájetMacc 0.1, which is comparable to low-mass sources and consistent with models for magneto-centrifugal jet launching. The knotted structure and velocity spread in both jets are interpreted as fossil signatures of a variable outflow rate. While the mean velocities in both lobes of the jets are comparable, the variations in mass outflow rate and velocity in the two lobes are not symmetric. This asymmetry suggests that the launching mechanism on either side of the accretion disk is not synchronized. For the HH 1042 jet, we have constructed an interpretative physical model with a stochastic or periodic outflow rate and a description of a ballistic flow as its constituents. We have simulated the flow and the resulting emission in position-velocity space, which is then compared to the observed kinematic structure. The knotted structure and velocity spread can be reproduced qualitatively with the model. The results of the simulation indicate that the outflow velocity varies on timescales on the order of 100 yr.
KW - Circumstellar matter
KW - Herbig-Haro objects
KW - ISM: individual objects: HH 1042
KW - ISM: individual objects: HH 1043
KW - ISM: jets and outflows
KW - Stars: formation
UR - http://www.scopus.com/inward/record.url?scp=84873646362&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201220635
DO - 10.1051/0004-6361/201220635
M3 - Article
AN - SCOPUS:84873646362
SN - 0004-6361
VL - 551
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A5
ER -