An Object Hidden in Plain Sight
First catalogued by the Infrared Astronomical Satellite (IRAS) back in 1983, the object known as IRAS 18293-0941 remained largely a mystery for decades. Located about 12,000 light-years away from Earth, it sits in a part of the Milky Way so dense with
interstellar dust and gas that it is practically invisible to traditional optical telescopes. However, renewed interest and the power of modern radio astronomy have allowed scientists to peel back these cosmic layers. By combining data from multiple powerful observatories, including the MeerKAT array in South Africa and the European Very Long Baseline Interferometry Network (EVN), an international team of researchers detected tell-tale signs of something extraordinary. What they found points to this 'forgotten' object being a very strong candidate for a class of celestial body scientists have been hunting for more than 30 years.
What Exactly is a Microblazar?
To understand a microblazar, it helps to first understand its much larger cousin: the blazar. A blazar is a type of quasar, which is an extremely luminous galactic core powered by a supermassive black hole millions or billions of times the mass of our Sun. As these giant black holes consume surrounding stars and gas, they shoot out enormous jets of plasma and radiation at near-light speeds. When one of these powerful jets happens to be pointed directly at Earth, we call it a blazar. A microblazar is essentially a scaled-down version of this. Instead of a supermassive black hole at the centre of a distant galaxy, a microblazar is powered by a much smaller, stellar-mass black hole (perhaps only 10 times the mass of our Sun) located within our own galaxy. This smaller black hole is part of a binary system, orbiting and 'nibbling' on a massive companion star. As it pulls material from the star, it too launches relativistic jets, and if one is aimed our way, it's classified as a microblazar.
The Evidence in IRAS 18293-0941
Astronomers studying IRAS 18293-0941 found that it fits the microblazar description almost perfectly. The system consists of a black hole, roughly 10 solar masses, orbiting a massive, hot star every 11 days. Crucially, radio observations revealed a one-sided jet of plasma shooting out from the system at about 75% of the speed of light. The reason it appears one-sided is due to an effect called 'Doppler boosting', where a jet moving towards an observer appears significantly brighter, while the jet moving away is too faint to see. This is a key observational fingerprint of a blazar-like object. While researchers note that the object didn't show the rapid brightness variations some theories predicted, the combined evidence strongly suggests one of its jets is pointed almost directly at Earth. Scientists have confirmed there is no danger to our planet from this distant jet.
A Unique Cosmic Laboratory
The confirmation of IRAS 18293-0941 as a microblazar would be a major breakthrough. Because blazars are billions of light-years away, they are difficult to study in detail. A microblazar in our own galactic backyard would provide an unprecedented, up-close look at the physics of how black holes launch these incredibly powerful jets. Scientists believe that changes in microblazars happen on much faster timescales than in their larger counterparts, allowing us to observe cosmic processes in fast-forward. Furthermore, this particular object is located near a mysterious region of space known to be a source of ultra-high-energy particles, which scientists have struggled to explain. The unseen jet pointing away from Earth could be acting as a giant particle accelerator, colliding with a dense molecular cloud and creating these very particles, potentially solving another cosmic puzzle.
