- Why in news
- On 21 October 2026, PIB reported that Raman Research Institute scientists found Centaurus X-3, a bright X-ray pulsar, accretes matter through an accretion disk, which is rare for high-mass binaries.
- What it is
- Centaurus X-3 is a high-mass X-ray binary: a magnetised neutron star (pulsar) orbiting a massive companion star. It was among the first X-ray pulsars discovered and is one of the most studied binary pulsars because of its brightness. The pulsar pulls matter from its companion and emits X-rays as the matter falls in.
- System type
- Centaurus X-3 is a high-mass X-ray binary where the companion is over 10 times the Sun's mass.
- Usual accretion in HMXBs
- In HMXBs, matter normally reaches the neutron star by direct capture of the companion's stellar wind, not through a disk.
- New finding
- The accretion stream, which carries matter from the disk to the pulsar, causes the variability in the secondary emission lines.
- Who did the study
- Raman Research Institute, an autonomous institution under the Department of Science and Technology, led by researcher Kinjal Roy.
- Neutron star
- A neutron star packs about a Sun's mass into a ball the size of a city; it is the dense remnant of a massive star's supernova collapse.
Don’t confuse with Primary vs secondary emission: Primary emission comes from the pulsar's magnetic poles. Secondary radiation is that radiation absorbed and re-emitted by surrounding structures such as the companion's surface, stellar wind or accretion stream.
Don’t confuse with Pulsar vs black hole: A pulsar is a spinning, highly magnetised neutron star. A black hole is a different, denser end-state with no surface.
Science and technology: 57 Prelims questions since 2013; most test the concept behind the news, not the news itself. In Mains, 12 news-triggered questions.
Why it matters
- Helps build better models of binary pulsars and how they accrete matter.
- Shows secondary emission lines can map structures that appear as point sources from Earth.
Problems
- X-ray binaries are so distant that they appear as point sources, so structures cannot be imaged directly.
- Existing emission models assume wind accretion in HMXBs and must be revised.
Way forward
- Include disk emission in future modelling of Centaurus X-3.
- Apply the secondary-line method to other binary pulsars.
Put in your answer
Indian space astronomy example: Raman Research Institute, an autonomous DST institution, led this study of a bright X-ray pulsar, showing Indian work in X-ray astronomy.
UPSC’s own questions that come close to this issue, from our Prelims and Mains banks.
No practice question for this one; the card may still help an answer. Why: Concept of pulsars and neutron stars is on syllabus; sci_tech asks concepts (36 of 57), but this study gives no testable fresh facts.
Worth revising until Prelims 2028: most news questions come within two years of the event.