Mystery Grows as Isolated Galaxies Create Stars with Unexplained Fuel Sources

Approximately 12 million light years from Earth lies an unusual galaxy. Its center has consistently formed new stars over the past 600 million years, yet the exact source of the fuel driving this star formation remains elusive.

The galaxy known as NGC 6789 was first identified in 1883, but it has only been in recent years that evidence of ongoing star formation has emerged. NGC 6789 is situated in a region dubbed the Local Void, located towards the Draco constellation, which is notably sparse in cosmic matter. It stands out as one of the few galaxies existing within this void, making it highly isolated compared to the majority of galaxies in the universe.

This isolation contributes to the enigma surrounding its star creation. Galaxies typically require gas to produce new stars, yet local voids contain very little gas. Being at least a billion years old, NGC 6789 should have depleted its initial reserves of gas; however, it has managed to generate approximately 100 million solar masses, equating to about 4% of its total mass, over the last 600 million years.

Ignacio Trujillo and researchers from the Canary Islands Institute of Astrophysics utilized the 2-meter twin telescope at the Teide Observatory in Tenerife to capture deeper images of galaxies than previously possible, aiming to uncover signs of events that might have introduced gas. If a merger with another galaxy or a previously undetected gas flow had occurred, it might have distorted the shape of NGC 6789.

However, the new images did not reveal any distortions. It is possible that NGC 6789’s formation left behind a substantial amount of gas or that there exists a faint gas pocket nearby that did not alter the galaxy’s shape at all. For now, the mystery remains unsolved.