Why in news?
An observational study led by the Indian Institute of Astrophysics, announced on 14 January 2026, traced magnetic fields from the scale of a molecular cloud down to the dense core of a budding star. Using polarisation measurements of dust emission in the dark cloud L328, the researchers uncovered how magnetic forces influence the birth of stars.
Background
Molecular clouds are cold (temperatures below 40 Kelvin) and dense (roughly 1,000 to 10,000 particles per cubic centimetre) regions of interstellar space. Comprised of gas and dust, they are the nurseries where new stars form. Gravity tries to pull gas together, but magnetic fields, turbulence and thermal pressure can resist collapse. L328 is a small molecular cloud about 700 light‑years away that contains a very faint protostar. Understanding how matter in such clouds condenses into stars is central to astrophysics.
Key insights from the study
- Mapping magnetic fields: Using the James Clerk Maxwell Telescope, the team measured polarised light from dust grains aligned with magnetic fields across scales from a few thousand astronomical units to about one parsec. This allowed them to reconstruct the direction and strength of magnetic fields from the cloud’s outskirts into its core.
- Ordered fields across scales: The observations show that magnetic field lines remain largely aligned from the large‑scale cloud down to the dense core. This continuity suggests the core inherits the field orientation of its parent cloud rather than developing a random orientation during collapse.
- Balancing forces: In L328, the energies associated with gravity, magnetic fields and turbulence were comparable and all greatly exceeded thermal energy. Strong magnetic fields and turbulent motions counteract gravity, slowing the collapse and shaping the core. As the core evolves, magnetic fields are expected to twist and amplify, eventually allowing a protostar to form.
Why it matters
These findings offer rare observational evidence that magnetic fields guide the early stages of star formation. By showing that magnetic structure is coherent across scales, the study supports theoretical models in which magnetic forces regulate how quickly clouds collapse and how angular momentum is transported. The results demonstrate the power of polarimetric observations and underscore the growing contribution of Indian astronomers to cutting‑edge astrophysics.
Source: Press Information Bureau
