Raman Research Institute scientists find hidden disk around pulsar Centaurus X-3

Indian researchers at the Raman Research Institute have discovered an accretion disk and a feeding stream surrounding Centaurus X-3, solving a long-standing question about how one of the sky's brightest X-ray pulsars feeds on its companion star.

The discovery, announced by the Union Ministry of Science and Technology, was led by researcher Kinjal Roy at the Bengaluru-based institute, an autonomous body under the Department of Science and Technology. The findings provide direct physical evidence of how this high-mass system transfers matter, offering astronomers worldwide a clearer framework to model binary pulsar behaviour.

Centaurus X-3 sits roughly 24,000 light years from Earth in the constellation Centaurus. It was among the first X-ray pulsars ever identified. The system consists of a highly magnetised neutron star — an object containing roughly the mass of the Sun compressed into a sphere the size of Bengaluru — locked in orbit with a massive companion star more than ten times heavier than the Sun.

What the scientists found

Pulsars produce primary radiation that sweeps across space from their magnetic poles like a cosmic lighthouse beam. When this intense beam strikes surrounding gas and material, those structures absorb and re-emit the energy as secondary radiation.

By examining four specific secondary emission lines in depth, the Raman Research Institute team discovered that the structure producing these shifting lines co-rotates with the pulsar itself.

That movement revealed an accretion stream: a directed flow funneling superheated matter straight towards the neutron star. Because an accretion stream can only form when feeding from a wider reservoir, its presence confirms that an accretion disk is actively circling Centaurus X-3.

Why the discovery matters

For high-mass X-ray binaries, pulling matter via an organized accretion disk rather than capturing loose stellar winds is relatively unusual. Confirming the disk and stream helps scientists pin down fundamental physical properties of the system, including the exact orientation of its orbit and the strength of its local magnetic field.

The achievement highlights the analytical depth of India's premier astronomical institutions. By extracting precise geometric signatures from complex secondary radiation, the researchers have turned one of astrophysics' oldest observational targets into a fresh testing ground for how extreme gravity behaves across deep space.