Taurus dark cloud reveals tiny gas drift that could kick-start star birth

The earliest stage of star formation may be less dramatic than once believed. Scientists studying a dark cloud in the Taurus region have found a faint internal movement, offering new insight into how cold gas begins to collapse and form stars.

According to SciTechDaily, observations of L1544, a dense and frigid core inside the Taurus molecular cloud, could represent the first time ambipolar diffusion has been identified in a prestellar core, an early stage in the birth of stars.

The study was led by scientists from Kyushu University and the Max Planck Institute for Extraterrestrial Physics.

Before a protostar emerges, material can accumulate into a prestellar core: a small, dense region of gas and dust that is just a few degrees above absolute zero.

Doris Arzoumanian from Kyushu University, the first author of the research, explained, “One key question we’re exploring is how magnetic fields influence star formation.”

Strong magnetic fields are often found in prestellar cores, but when these fields are especially powerful, they can hold back the pull of gravity and postpone the start of star formation. The team found evidence for this effect in a small difference in speed between charged and neutral gases.

By using the IRAM 30-meter telescope, the team tracked the ion N2D+ and the neutral molecule para-NH2D, discovering a velocity difference of about 0.03 miles per second, which aligns with ion-neutral drift and indicates ambipolar diffusion.

The findings shed light on a little-studied stage in the process of star formation. In clouds such as L1544, magnetic fields can slow the collapse that leads to the formation of new stars.

Ambipolar diffusion occurs when neutral gas slips inward, while charged particles remain tied to magnetic fields. Over time, this weakens the magnetic support, allowing gravity to take control.

Stars play a central role in shaping planets and providing the ingredients for life. Gaining a clearer picture of how a quiet cloud collapses into a protostar could help researchers refine their models of how solar systems come together.

By studying precise radio data, the team compared how ions and neutral particles move inside the core. This approach gives astronomers a new tool to test their theories of star formation using real-world observations.

The findings also suggest that as prestellar cores grow denser, reduced ionizing radiation reduces the number of charged particles, allowing neutral material to collapse inward. Additional observations of other cores could verify if this pattern is common, helping scientists develop a more reliable framework for predicting star formation.