JWST finds a small star-forming complex: What's so special?
16 Sep 2025

Astronomers have discovered a faint and small star-forming complex using the James Webb Space Telescope (JWST).

The new complex, named LAP2, was found behind the galaxy cluster Abell 2744.

The discovery is detailed in a research paper published on the arXiv preprint server.

The finding could provide insights into the formation of Population III stars, which are thought to be the first stars formed after the Big Bang.

LAP2 is a small and faint star complex
Complex characteristics

LAP2, or Lensed And Pristine 2, was detected at a spectroscopic redshift of z = 4.19.

The astronomers first obtained two mirrored images, LAP2-a and LAP2-b, through spectroscopic observations.

The high magnification factors of these images suggest that LAP2 is a small and faint star complex with an estimated size of less than 33 light-years and intrinsic ultraviolet luminosity of -12.2.

It has less than 0.6% of solar metallicity
Stellar properties

The mass of LAP2 is estimated to be a few tens of thousands of solar masses, while its metallicity is less than 0.6% of solar metallicity.

The specific star-formation rate (sSFR) of this complex is 100 per billion years and its age is assumed to be less than 10 million years.

These characteristics make LAP2 one of the most metal-poor objects known so far, offering a rare glimpse into galaxies under conditions similar to those in the early universe.

Future observations will help in understanding of LAP2
Upcoming research

The authors of the paper plan more observations of this star-forming complex to further explore its properties. The system is scheduled to be observed with NIRSpec/IFU in prism mode for a total of 17.4 hours.