Outflows, envelopes, and disks as evolutionary indicators in Lupus YSOs

VAZZANO, MARÍA MERCEDES; FERNÁNDEZ-LÓPEZ, MANUEL; PLUNKETT, ADELE L.; DE GREGORIO-MONSALVO, ITZIAR; SANTAMARÍA-MIRANDA. ALEJANDRO; TAKAHASHI, SATOKO; LOPEZ, C.

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2021

0004-637X

Context. The Lupus star-forming complex includes some of the closest low-mass star-forming regions, and together they house objectsthat span evolutionary stages from pre-stellar to pre-MS.Aims. By studying 7 objects in the Lupus clouds from prestellar to protostellar stages, we aim to test if a coherence exists betweencommonly used evolutionary tracers.Methods. We present ALMA observations of the 1.3 mm continuum and molecular line emission that probe the dense gas and dust ofcores (continuum, C18O, N2D+) and their associated molecular outflows (12CO). Our selection of sources in a common environment,with identical observing strategy, allows for a consistent comparison across different evolutionary stages. We complement our studywith continuum and line emission from the ALMA archive in different bands.Results. The quality of the ALMA molecular data allows us to reveal the nature of the molecular outflows in the sample by studying their morphology and kinematics, through interferometric mosaics covering their full extent. The interferometric images inIRAS 15398-3359 appear to show that it drives a precessing episodic jet-driven outflow with at least 4 ejections separated by periods of time between 50 and 80 years, while data in IRAS 16059-3857 show similarities with a wide-angle wind model also showingsigns of being episodic. The outflow of J160115-41523 could be better explain with the wide-angle wind model as well, but newobservations are needed to further explore its nature. We find that the most common evolutionary tracers in the literature are usefulfor broad evolutionary classifications, but are not consistent with each other to provide enough granularity to disentangle differentevolutionary stage of sources that belong to the same Class (0, I, II, or III). The evolutionary classification revealed by our analysiscoincides with those determined by previous studies for all our sources except J160115-41523. Outflow properties used as protostellar age tracers, such as mass, momentum, energy and opening angle, may suffer from differences in the nature of each outflow, andtherefore detailed observations are needed to refine evolutionary classifications. We found both AzTEC-lup1-2 and AzTEC-lup3-5to be in the pre-stellar stage, with the possibility that the latter is a more evolved source. IRAS 15398-3359, IRAS 16059-3857 andJ160115-41523, which have clearly detected outflows, are Class 0 sources, although we are not able to determine which is youngerand which is older. Finally Sz 102 and Merin 28 are the most evolved sources in our sample and show signs of having associatedflows, not as well traced by CO as for the younger sources.