Outflows from the youngest stars are mostly molecular

Area of Science:

• * Astrophysics
• * Star Formation
• * Planetary Science

Background:

• * Star and planet formation involves both matter accretion and expulsion via supersonic jets.
• * Young protostars exhibit the most powerful jets, but are obscured by dust, limiting observations.
• * The hot, atomic, ionized, and molecular constituents forming the jet's backbone remain largely unobserved.

Purpose of the Study:

• * To investigate the composition of young protostellar jets, particularly their hot constituents.
• * To explain the origin of the 'green fuzzies' observed in protostellar outflows.
• * To probe the earliest stages of jet evolution using infrared observations.

Main Methods:

• * Near-infrared observations using the James Webb Space Telescope (JWST).
• * Targeted observation of Herbig-Haro 211, an outflow from a young protostar.
• * Analysis of emission from hot molecules, atomic, and ionized gases.

Main Results:

• * Copious emission from hot molecules detected in the Herbig-Haro 211 outflow.
• * The 'green fuzzies' are explained as emission from these hot molecules.
• * The jet spine is found to be almost purely molecular, with minimal atomic or ionized emission.
• * The outflow exhibits slower propagation compared to more evolved jets.

Conclusions:

• * The backbone of young protostellar jets is predominantly molecular.
• * JWST's infrared capabilities are crucial for observing obscured, hot components of protostellar outflows.
• * This study provides new insights into the early stages of jet formation and evolution.