# ALMA finds an 8 pc CO jet of 33–60 K gas aligned with gamma-ray binary LMC P3

- Published: 2026-11-12 10:52 UTC
- Section: Sky & Space › Astronomy
- Tags: LMC P3, DEML 241, gamma-ray binary, ALMA observations, CO jet, microquasar, Large Magellanic Cloud, accretion disk, Yasuo Fukui, HESS J1023-575
- URL: https://realtech.media/news/rt-01a92e35a3a1e25f636d4252_alma_finds_an/

**Gas heated to 33–60 K, against about 15 K nearby, lines up with the most luminous gamma-ray binary known. The authors link it to a microquasar jet.**

![ALMA finds an 8 pc CO jet of 33–60 K gas aligned with gamma-ray binary LMC P3](https://realtech.media/media/2026/11/d78154c430c47d43.jpg)
*Earth.com*

A team led by Yasuo Fukui of Nagoya University, with colleagues at Gifu University, has used ALMA to map carbon monoxide (CO) emission around DEML 241/LMC P3, the most luminous known gamma-ray binary made of a compact object and an O star. The results appear in The Astrophysical Journal Letters. The authors found a one-sided jet-like CO feature 8 pc long and 1 pc wide, aligned with LMC P3 [1].

LMC P3 lies in the Large Magellanic Cloud and was first reported in 2016. It was the first gamma-ray binary found outside the Milky Way. The two objects orbit each other about every 10 days, inside the remnant DEM L241. The ALMA observations began in 2022.

## Warm CO streak

The kinetic temperature of the CO jet is 33–60 K, compared with about 15 K in a nearby CO cloud with no jet [1]. No radiative heat source was found near that cloud. The team found no hot stars close enough to have warmed the streak by their light. A second, weaker jet candidate lies at a slightly different orientation, about 16 degrees from the first. The authors note that a slowly changing jet direction could explain both, but this has not been tested.

The jet itself has not been detected in radio waves, X-rays or gamma rays. The streak appears only north of the binary, where the gas cloud is. The ALMA map did not cover the south side.

## Microquasar interpretation

The authors interpret the heating as shock heating by a microquasar jet. In this picture the compact object has an accretion disk fed by the O star winds [1]. The CO jet matches existing magnetohydrodynamical simulations of a microquasar jet interacting with an interstellar cloud. This supports mass accretion in LMC P3 as the origin of the gamma rays. The paper does not name the type of compact object.

A similar CO jet was recently identified near the microquasar candidate HESS J1023-575 in the Milky Way, which makes LMC P3 the second such case. The authors suggest that submillimeter searches for straight warm CO streaks could help find microquasars in the dusty central regions of the Galaxy. The team plans sharper ALMA observations that resolve details below about three light-years, which would improve the temperature estimates and show whether the jet direction shifts.

## Sources

1. [The Astrophysical Journal Letters](https://doi.org/10.3847/2041-8213/aea0cb)
2. [Earth.com](https://www.earth.com/lifestyle/what-is-fueling-the-brightest-gamma-ray-star-pair-ever-found)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-01a92e35a3a1e25f636d4252_alma_finds_an/