ALMA spots 'dragon egg' that may represent the earliest stages of massive star formation

Astronomers have discovered an exceptionally small core, dubbed the "dragon egg," located in the Dragon Cloud region 16,300 light-years away. This core, which is estimated to have a mass 20-30 times that of the Sun, may represent an early stage in the formation of a massive star. The discovery was made using the Atacama Large Millimeter/submillimeter Array (ALMA) and published in Astronomy & Astrophysics.

The core, known as C2c1a(a), is embedded in a much larger reservoir of cold gas and dust, with a mass of at least 110 times that of the Sun. This provides the necessary material for the formation of a massive star. Researchers found that the core is dominated by a single compact central source, indicating that most of the emission comes from a region concentrated at the core.

The spectral analysis revealed little glowing gas at the center of C2c1a(a), suggesting that the core is not hot. However, there is some faint emission that could be due to either the core being cool or the thick dust blocking the glow. No clear signs of outflows, such as energetic jets, were detected from the compact source, though the presence of a weak, embedded, or unfavorably oriented outflow cannot be entirely ruled out.

Compared to the mass of the core, the clump around it holds about 1,061 times the mass of the Sun but emits little energy for its size. This indicates that the core is in a very early stage of high-mass star formation. The researchers noted that the core's properties suggest it fits the initial conditions of monolithic core-accretion models for massive star formation, but more observations are needed to distinguish between different formation pathways.