The winds from HL Tau.

Area of Science:

• * Astrophysics
• * Star Formation and Evolution

Background:

• * Outflowing motions (winds, jets, molecular outflows) are ubiquitous in star formation.
• * These motions are influenced by their environment and the star formation process.
• * Understanding these outflows is crucial for comprehending star formation.

Purpose of the Study:

• * To investigate high-velocity molecular gas removal during star formation using ALMA data.
• * To contextualize these motions with the protostar's jet and accretion disk.
• * To quantify the characteristics of molecular outflows in HL Tau.

Main Methods:

• * Utilized Atacama Large Millimeter/submillimeter Array (ALMA) Science Verification data.
• * Analyzed high-resolution (∼1 arcsec) observations of carbon monoxide (CO) (J=1-0).
• * Quantified outwards velocities and opening angles of molecular gas.

Main Results:

• * Detected evidence of a bipolar outwards molecular flow in HL Tau.
• * Measured the outflow's opening angle, starting at 90° and narrowing to 60°.
• * Determined an inclination-corrected outwards velocity of approximately 2.4 km/s.
• * Suggested magnetic collimation as a cause for the narrowing angle.

Conclusions:

• * Molecular outflows are a significant component of the star formation process in HL Tau.
• * The observed outflow geometry and velocity provide insights into the physical mechanisms at play.
• * Magnetic fields likely play a role in collimating the outflowing gas.