This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Astronomers identified an exceptionally tiny core that may represent an early stage in the formation of a massive star. Located in an infrared-dark area called Dragon Cloud, the core is nicknamed the "dragon egg." The paper, accepted for publication in Astronomy & Astrophysics, was posted to the arXiv preprint server on Oct. 5.
How giant stars, with masses eight times greater than the sun, form is still a matter of debate in the scientific community. There are two main ideas. One says that a dense cloud of gas first condenses into a massive "pre-stellar" core, which then collapses to form a single giant star.
Another says the star begins small and grows by pulling in material from the larger clump around it. Researchers think that if they directly observe a compact, massive yet young concentration of mass, they will be able to lean toward one of these ideas. Such cores, however, are hard to detect, and if they are found, their interpretations are sometimes complicated by nearby star formation and stellar activity.
Astronomers observed one such promising candidate called C2c1a in the C2c1 region inside an infrared-dark cloud known as Dragon Cloud, located about 16,300 light-years away. Nicknamed the "dragon egg," the core appears to contain some 20 to 30 times the sun's mass. The clump around it holds roughly 1,061 times the mass of the sun but gives off little energy for its size.
This, researchers say, is a sign of a "very early stage of high-mass star formation." Earlier data could not confirm whether C2c1a is one compact object, where its mass is concentrated, or whether a protostar has formed. In this study, the team led by Ashley Thomas Barnes of the European Southern Observatory (ESO) used new ALMA Band 6 observations to obtain a high-resolution view of the dragon egg. "These data are among the highest-resolution and most sensitive ALMA Band 6 observations currently available for similar targets," researchers write in their paper.
High-resolution data revealed that the main region itself has six components: C2c1a(a), C2c1b, and four fainter structures in the intervening envelope. The emission was dominated by the central component C2c1a(a). This indicates that most of the emission comes from a centrally concentrated region.
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