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Astronomers from Argentina and Spain have performed near-infrared observations of a massive young stellar object known as MYSO G29.862−0.0044. The observational campaign sheds more light on the nature of this object and its unique morphology. The new findings are in a paper published August 13 on the arXiv preprint server.

Massive young stellar objects (MYSOs) are stars in the very early stage of formation and the progenitors of massive main-sequence stars. However, due to their short formation timescale (about 10,000–100,000 years) and the severe extinction by the surrounding gas and dust, observations of MYSOs remain challenging.

Located some 20,200 light years away, MYSO G29.862−0.0044 (YSO-G29 for short), is a massive young stellar object associated with the star-forming region G29.96-0.02. The object is likely embedded within a dense molecular core.

Previous near-infrared observations have found that YSO-G29 is composed of two nebulosities separated by a dark lane (a cavity), which suggests that it is a typical disk plus jets system, however highly asymmetric. It is assumed that the observed near-infrared features may arise from a single source or from confusion caused by an unresolved system of YSOs. It could also be due to complex protostar dynamics.

In order to confirm which of the hypotheses is true, a team of astronomers, led by Sergio Paron of the University of Buenos Aires in Argentina, decided to take a closer look at YSO-G29, hoping to disentangle the nature of this object and its star-forming region.

"Hence, we decided to carry out new observations to investigate the nature of this region and its features in greater detail. We used the Jansky Very Large Array (JVLA) to map the radio continuum emission and the NIFS instrument at Gemini-North to perform near-infrared spectroscopy," the scientists wrote in the paper.

The observations detected molecular outflows (having a systemic velocity of about 101 km/s) associated with YSO-G29, at small spatial scales. Moreover, the observational campaign identified a compact radio continuum source, a likely compact region of ionized atomic hydrogen (HII region) or an ionized jet of a massive protostar, located some 0.065 light years from the main millimeter core.

The astronomers noted that the collected data indicate the presence of a protostar (a non-detected massive star), embedded within the molecular core of YSO-G29. Therefore, they assume that YSO-G29 could be a binary system composed of a star later than B3 spectral type, or a protostar, non-ionizing yet, and a B1 type star generating an ultracompact HII region.

Furthermore, the researchers suppose that if YSO-G29 is a binary system, then one of its components may have generated a cavity in the surrounding interstellar medium. The observational evidence suggests that this cavity was partially disrupted by a molecular outflow likely generated by the other component of the system.

"We can explain the nature of the intriguing near-IR features previously observed: cone-like structures produced by jets/winds of one of the components of the binary system that cleared out the surroundings were disrupted by a molecular outflow probably from the other component," the authors of the paper concluded.