Details of the new dwarf galaxy discovered on the outskirts of the Milky Way

The huge amount of Notes That allowed Telescopes Cutting-edge technologies have provided scientists with hundreds of new developments that occur every week. Now, a team of astronomers from Naples has discovered New star system On the outskirts of milky way As part of the Kilo Degree Survey (KiDS), a group of Visual surveys in it Southern sky. The new system is called Sextanze IIIt is likely a very faint dwarf galaxy.

KiDS is a large-scale multi-band survey using the VLT Survey Telescope (VST) at the Paranal Observatory of the European Southern Observatory in Chile. Since 2011, an area of ​​1,350 square degrees of the Earth's surface has been mapped Night sky In four broadband filters (u, g, r, i). Although KiDS focuses on piecing together large-scale structures in the universe, it can also detect others Extragalactic stars Low surface gloss.

For this reason, a team of Astronomy scientists Directed by Massimiliano Gato The Capodimonte Astronomical Observatory in Naples, Italy decided to conduct an operation Extensive search to Weak star systems Unknown people with KiDS, as stated in the article published in arXiv. To do this, they tracked the density of low-luminosity stars in the system's latest data release (DR4), which yielded promising results.

“We report the discovery of large, compact overdensities of ancient, metal-poor stars in the fourth data release from the KiDS study (DR4),” the authors explained in the paper.

The team has identified a very promising hyperdensity of stars in the constellation Sextan. Follow-up observations of this discovery were made using the 8.2-meter Subaru telescope. The conclusions confirmed that it is a star system located about 473 thousand light-years away.

Initially, astronomers named the new system KiDS-UFD-1 and named it Sextans II. The collected data indicate that Sextance 2 is relatively small, with a half-light radius of about 629 light-years, while its mass is estimated at 4,910 solar masses. The system has a metallicity of -1.5 dex (a parameter to measure the concentration of metals in a celestial body), an ellipticity of 0.46 and is at least 10 billion years old.

According to the authors of the article, the results indicate this Sextans II is a weak, old, and mineral-poor system. The Gatto team concluded that it is a faint spherical satellite of the Milky Way, most likely an extremely faint dwarf (UFD) galaxy. In general, these are the least luminous, most dark matter-dominant, and least chemically evolved galaxies known.

However, researchers do not rule out the possibility that Sextans II is a disruptive globular cluster (a spherical group of stars that normally orbits the galactic core as if it were a satellite), adding that more research on this system is needed to confirm it. Its true nature.

Experts have dedicated themselves to monitoring this discovery in order to advance its definition and classification, because, they say, it could make new contributions to the way our Milky Way Galaxy originated.