Near-IR imaging toward a puzzling young stellar object precessing jet

S. PARON; C. FARIÑA; M. E. ORTEGA

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Lugar: Paris; Año: 2016 vol. 593

0004-6361

Aims: The study of jets that are related to stellar objects information is Important because it enables us to understand the historyof how the stars have built up their mass. Many studies currentlyexamine jets towards low-mass young stellar objects, while equivalentstudies toward massive or intermediate-mass young stellar objects arerare. In a previous study, based on 12CO J = 3-2 and publicnear-IR data, we found highly misaligned molecular outflows toward theinfrared point source UGPS J185808.46+010041.8 (IRS) and some infraredfeatures suggesting the existence of a precessing jet. Methods:Using near-IR data acquired with Gemini-NIRI at the JHKs broad- andnarrowbands centered on the emission lines of [FeII], H2 1-0S(1), H2 2-1 S(1), BrGamma, and CO 2-0 (bh), we studied thecircumstellar environment of IRS with an angular resolution between0.35" and 0.45". Results: The emission in the JHKsbroadbands shows in great detail a cone-shaped nebula extending to thenorth-northeast of the point source, which appears to be attached to itby a jet-like structure. In the three bands the nebula is resolved in atwisted-shaped feature composed of two arc-like features and abow-shock-like structure seen mainly in the Ks band, which stronglysuggests the presence of a precessing jet. An analysis of proper motionsbased on our Gemini observations and UKIDSS data additionally supportsthe precession scenario. We present one of the best-resolved cone-likenebula that is most likely related to a precessing jet up to date. Theanalysis of the observed near-IR lines shows that the H2 iscollisionally excited, and the spatially coincidence of the [FeII] andH2 emissions in the closer arc-like feature suggests thatthis region is affected by a J shock. The second arc-like featurepresents H2 emission without [FeII], which suggests anondissociated C shock or a less energetic J shock. The H21-0 S(1) continuum-subtracted image reveals several knots and filamentsat a larger spatial scale around IRS. These perfect match thedistribution of the red- and blueshifted molecular outflows discoveredin our previous work. An unresolved system of YSOs is suggested toexplain the distribution of the analyzed near-IR features and themolecular outflows, which in turn explains the jet precession throughtidal interactions.