News on two jets in Lupus 3

Abstract

Context. Jets from solar-type and low-mass stars are typical manifestations of stellar youth. Shocks along these jets produce visible, generally fast-moving Herbig-Haro objects whose proper motions are easily measured in nearby star-forming regions using images taken just a few years apart. Herbig-Haro objects have now been observed in association with objects close to the substellar boundary. Aims. We present second-epoch observations of the central area of the Lupus 3 star-forming region that include two of its most interesting Herbig-Haro systems. One is HH 228, produced by the classical T Tauri star Th 28 (=Sz 102), whereas the other is HH 600, which has its origin in the very low-mass star Par-Lup3-4. Methods. Narrow-band imaging through filters centered on the Hα and the [SII] lines was obtained with the FORS2 instrument at the Very Large Telescope (VLT) in mid-2010. The images obtained were compared to others obtained in early 2003, leading to the discovery of HH 600. Results. New Herbig-Haro objects are found at large distances from Th 28 and to be associated with it, representing an extension of the HH 228 jet to a projected distance of 0.32 pc from Th 28. The farthest Herbig-Haro object is HH 989, whose possible relationship with Th 28 had been already suggested in a previous study but is now kinematically confirmed. We find other likely Herbig-Haro objects whose proper motions are less indicative of a connection with Th 28, but which may be caused by oblique shocks near the outer walls of its jet. For the HH 600 jet, the knot discovered by ourselves in 2003 to the southeast of Par-Lup3-4 is found to have clearly moved and faded. Using high resolution spectroscopy obtained in 2003 and the proper motion that we can measure now, we determine a spatial velocity of 170 ± 30 km s −1 . The northwestern jet is found to have grown in prominence in the intervening years. The possible relationship of other Herbig-Haro objects in the region with Th 28, Par-Lup3-4, and other young stellar objects in the area is discussed.

ESO-Hα574 and Par-Lup 3-4 jets: Exploring the spectral, kinematical, and physical properties

“…The jet which extends to ± 3 on either side of the source displays no asymmetries in agreement with Comerón & Fernández (2011). Comerón & Fernández (2011) compare images of this jet with earlier observations and point out that the appearance of the jet is much more symmetric than in previous observations with both the blue and red-shifted lobes displaying similar intensities. They report the fading of the knot HH 600 between their 2003 and 2010 observations.…”

“…Par-Lup3-4 (16 h 08 m 51 s 44, -39•05 30.5 ) found in the Lupus III cloud (d = 200 ± 40 pc, Comeron et al 2003), is a VLM object driving a small-scale jet at a PA of ∼ 130 • (HH 600) (Comerón & Fernández, 2011). Its spectral type and mass have been estimated at M5 and 0.13 M respectively (Comerón et al , 2003;Alcalá et al, 2014).…”

No substellar objects at the center of the Lupus 3 star-forming cloud

“…A faint close companion is also detected in the K S -band images of the jet-driving, very low-mass star Par-Lup3-4 (Fernández & Comerón 2005;Huélamo et al 2010;Comerón & Fernández 2011). The companion is located 1 2 to the Merín et al (2008) Mass estimated from HK S photometry alone assuming age ∼2 Myr SSTc2d J160858.3-390749 16:08:58.30 -39:07:49.4 ∼0.4 Deeply embedded, confirmed as Class II YSO by Merín et al (2008) Mass estimated from HK S photometry alone assuming age ∼2 Myr Sz 114 Candidate member in Nakajima et al (2000), Class III in Merín et al (2008).…”

An irradiated jet in M 17

“…However, the jet in M 17 appears to be less collimated, and the knots are much less closely spaced than in HH 34S. In that regard, the string of knots forming the system HH 228/HH 989, associated with the extreme T Tauri star Th 28 in Lupus 3 (Comerón & Fernández 2011), is a closer match to the system formed by knots A to C. If placed at the distance of M 17, the individual knots composing HH 228/HH 989 would have typical sizes around ∼2 , thus appearing marginally resolved in our images, and separations between consecutive knots around ∼6. 5, comparable to the spacing between features A, B, and C. One of them, HH 989 C, is a very likely component of the system of knots, but it lies away from the axis and has a proper motion different from that of the other knots, perhaps being an analogous of knot B (slightly off-axis and with a radial velocity similar to that of the HH region) in the system reported here.…”