A black hole 12,000 light-years away is pointing its jet toward Earth

A black hole about 12,000 light-years from Earth is firing a jet of plasma at a large fraction of the speed of light, and the jet points roughly in our direction. The system, a dust-buried binary star known only by its catalogue name IRAS 18293-0941, is the strongest case yet for a “microblazar”: a star-sized version of the blazars that shine from the cores of distant galaxies.

That matters for two reasons. Every blazar known until now sits millions or billions of light-years away, so a miniature one inside the Milky Way is a laboratory next door. And the team behind the discovery argues that the system’s second jet, the one aimed away from us, is slamming into a cloud of gas where it may be accelerating particles to around a quadrillion electronvolts, more than a hundred times the energy of the proton beams in the Large Hadron Collider.

Microquasars, binary systems in which a black hole or neutron star pulls gas off a companion and throws some of it back out in two narrow jets, have been known for decades. When such a jet points close to our line of sight, relativity makes the half racing toward us look far brighter while the receding half almost vanishes. That effect, called Doppler boosting, is what makes blazars so bright. A Galactic version had long been predicted, but every earlier candidate fell apart under scrutiny.

How a jet hid behind a wall of dust

“It sits behind so much dust that it is practically invisible in standard optical images,” said lead author Josep Martí of the University of Jaén in Spain. The object had been flagged as a possible X-ray binary and then, in his words, “catalogued decades ago and then more or less forgotten.”

Radio light, which passes through dust, gave it away. Survey images taken years apart all showed a compact core and a single lobe on one side, with nothing on the other: the mark of a steady jet rather than a one-off flare.

Archival images from the Very Large Array and an eight-hour observation with the European VLBI Network, which links radio dishes across continents into one virtual telescope, traced the same one-sided jet from the smallest scales up to the lobe. The approaching jet is at least 26 times brighter than any trace of its twin, which requires gas moving faster than two-thirds of light speed within about 48 degrees of our line of sight. At an illustrative three-quarters of light speed, the angle comes out near 26 degrees.

The decisive test was position. The jet’s radio position, measured to thousandths of an arcsecond, matches the star’s position from the European Space Agency’s Gaia satellite, ruling out the usual impostor: a distant active galaxy lying behind a Milky Way star. That, said Benito Marcote of the Joint Institute for VLBI ERIC in the Netherlands, “confirmed it: the jet belongs to the stellar system.”

Optical monitoring from Spanish telescopes and the Zwicky Transient Facility found a brightness wobble of just 0.02 magnitudes repeating every 11.38 days, the pair’s orbital period. So small a wobble, with no eclipses, means we see the orbit almost face-on, tilted about 20 degrees. Jets launched perpendicular to that orbit should point close to us, exactly as the radio data say. Spectra from Calar Alto point to a hot, massive giant or supergiant companion shedding gas at 300 to 400 kilometres per second into a dusty envelope.

The other jet hits a cloud

The jet aimed toward us runs into thin gas and spreads into a broad, faint bubble. The receding jet stays narrow until it crashes into dense material tens of parsecs away (one parsec is about 3.26 light-years). There, radio images from South Africa’s MeerKAT array show a compact hotspot ringed by glowing hydrogen and warm dust: a shock front, like the bow wave of a boat.

Surveys of carbon monoxide gas place a large molecular cloud along that line of sight at the same distance, 3.6 kiloparsecs, which is how the team arrives at the 12,000 light-year figure. The hotspot also overlaps with LHAASO J1831-1007u*, a source of gamma rays above 100 teraelectronvolts detected by the Large High Altitude Air Shower Observatory in China.

“The elegance is that the accelerator engine and target are two different objects, tens of parsecs apart,” said co-author Pedro Luque-Escamilla of the University of Jaén. In the team’s model, protons accelerated by the jet escape into the cloud and collide with its gas, producing short-lived particles called pions that decay into the gamma rays LHAASO sees. Built around a 10-solar-mass black hole feeding at a furious rate, the model reproduces the system’s light from radio waves to the highest gamma-ray energies.

How it compares

Blazars in other galaxies are powered by supermassive black holes weighing millions to billions of Suns, and even one of the nearest, Markarian 421, lies roughly 400 million light-years away. IRAS 18293-0941 is powered by a black hole modelled at about 10 solar masses and sits less than half as far from us as the black hole at the centre of the Milky Way, Sagittarius A*, which is about 26,000 light-years away.

Earlier contenders never held up. V4641 Sagittarii lacked a steady jet and an independent measure of its orientation, and the black hole binary 4U 1543-47 produced a one-sided jet tilted less than 27 degrees from our line of sight only during an outburst. IRAS 18293-0941 has a jet that looks the same across years of surveys plus an orbit whose tilt can be measured separately, the combination astronomers use to classify blazars.

The system also joins a growing list of microquasars linked to the most energetic light in the galaxy. Gamma-ray observatories have recently tied SS 433 and V4641 Sagittarii to ultra-high-energy emission, adding to evidence that supernova remnants are not the Milky Way’s only major particle accelerators.

What it doesn’t settle

The paper itself calls IRAS 18293-0941 a “compelling Galactic microblazar candidate,” not a closed case.

The black hole has not been weighed. Its 10-solar-mass figure is a model assumption, and the companion’s type is uncertain: the dust hides the starlight so badly that a luminous blue variable, a rarer and unstable kind of massive star, cannot be excluded.

The distance is a second weak point. Gaia returned a formally negative parallax, which gives no usable distance, and older studies placed the system at 8 to 9 kiloparsecs, more than twice as far. The 12,000 light-year figure assumes the jet really is hitting the cloud at 3.6 kiloparsecs.

A classic blazar hallmark is also missing: rapid flickering. The team found no optical variation within an hour down to 0.01 magnitudes and argues that the dusty envelope smooths out fast changes, a plausible explanation that still needs testing.

Finally, the link to the gamma rays rests on position and modelling. LHAASO J1831-1007u* has previously been tentatively tied to other objects in the same crowded region, and the speed and angle of the jet are bounds rather than direct measurements.

Common questions about the microblazar

What is a microblazar?

A microblazar is a microquasar whose jet points close to our line of sight. It is a binary system in which a stellar-mass black hole or neutron star feeds on a companion star and launches jets. Because the jet heads roughly toward us, relativity makes it look brighter, just as in the giant blazars of distant galaxies.

Is a black hole jet pointed at Earth dangerous?

No. IRAS 18293-0941 is about 12,000 light-years away, and the jet aimed toward us spreads into a broad, faint bubble close to its source. What reaches Earth is faint radio emission, X-rays and gamma rays that only sensitive observatories can detect.

How far away is IRAS 18293-0941?

The team estimates about 3.6 kiloparsecs, roughly 12,000 light-years, based on the molecular cloud its jet appears to strike. That is less than half the distance to the centre of the Milky Way, although older estimates put it more than twice as far away.

What is the difference between a microquasar and a blazar?

Both are jets from a feeding black hole. A blazar is powered by a supermassive black hole in the core of a galaxy, weighing millions or billions of Suns, and its jet points at us. A microquasar is powered by a black hole or neutron star of a few solar masses in a binary system. A microblazar combines the two: a microquasar whose jet happens to point our way.

The study, by a team from Spain, the Netherlands and Argentina, was posted as a preprint on 1 September 2026 and accepted by Astronomy & Astrophysics; the Netherlands Research School for Astronomy announced it on 22 September. It draws on a European VLBI Network run on 26 May 2024, optical monitoring through 2024 and Calar Alto spectra from mid-2025. Next comes targeted follow-up of the collision site. “We are planning more observations of the hot spot where the jet hits,” Marcote said.

Reference: Martí et al., “A Galactic microblazar as a potential accelerator of ultra-high-energy particles,” Astronomy & Astrophysics, 2026. DOI: 10.1051/0004-6361/202661105

Tags: astronomy, black holes, Milky Way, IRAS 18293-0941, LHAASO, microblazar