ALMA reveals secrets of the Universe after observing hidden seeds of giant stars

The incredible capabilities of ALMA have allowed us to obtain unprecedented images of the birth of massive stars, where the necessary elements for the emergence of life are forged. Thanks to the Atacama Large Millimeter/submillimeter Array (ALMA), an international research team led by Kaho Morii, Patricio Sanhueza, and Fumitaka Nakamura made a major discovery by revealing 800 “star seeds” inside huge cosmic clouds. The discovery is key to understanding the enigmatic process of formation of massive stars, which in turn play a fundamental role in the formation of the building blocks of life.

These results were achieved thanks to the incredible sensitivity and resolving power of ALMA, which enabled the research team to observe in detail 39 massive cosmic clouds known as Infrared Dark Clouds (IRDCs), where massive stars theoretically form. The research team used ALMA to identify 800 star seeds, or molecular cloud nuclei, in what turned out to be the largest find to date. To their surprise, 99% of these seeds lack the mass necessary to form massive stars, leading to the deduction that such stars must evolve differently from smaller stars and that the main factor in their formation may be core density. instead of its mass. Kaho Morii, a graduate student at the University of Tokyo, comments: “With ALMA’s advanced capabilities we have greater certainty that some massive stars have a unique pattern of evolution. It seems that being in a dense environment is more important than we thought for the growth of these cosmic giants.”

Patricio Sanhueza, a Chilean who works at the National Astronomical Observatory of Japan and participates in ALMA, adds: “This catalog of starseeds is monumental. It is the basis for revolutionizing our understanding of massive star formation processes and refining our models.” The crucial role that ALMA played in this historic discovery allowed the scientific community to take a big step forward in the search for answers about the birth of massive stars, and helps to better understand the emergence of elements and the complexity of the Universe.

The results of this study are reported in the article by Kaho Morii et al. “The ALMA Early-Stage 70-μm High-Mass Dark Clusters (ASHES) Study. IX. Physical properties and spatial distribution of nuclei in IRDC’ (‘ALMA mapping of early-stage 70 μm massive clusters [ASHES]. IX. Physical properties and spatial distribution of nuclei in IRDC’, published in The Astrophysical Journal on June X of 2023 (doi:10.3847/1538-4357/acccea). This research was supported by funds from the Japan Society for the Advancement of Science (JP22J21529, JP22H01271 and JP23H01221), the WINGS graduate program of the University of Tokyo, the German Research Society (DGF) project SFB 881 entitled “ The Milky Way system” (project 138713538, subproject B1) and the BASAL FB210003 project of the National Agency for Research and Development of Chile (ANID).

The vision of Professor Guido Garay

“Massive stars form in large clumps of molecular gas and dust, called stellar nurseries. In this project eleven (11) of these stellar nurseries were observed to determine what are the characteristics of the smaller structures within them that will give rise to individual stars. We found that these stellar ‘seeds’ have masses less than those of massive stars (30 or more solar masses) and that therefore a continuous process of gas accretion towards the stellar cradles is needed to form massive stars”, he also stated. PhD from Harvard University. For Dr Garay “The finding is very relevant in the field of star formation, a discovery that was led by a doctoral student from the University of Tokyo, guided by my former student Patricio Sanhueza, and carried out in collaboration with a dozen astronomers. from all over the world (including them from Harvard and Max Planck).

Each collaborator contributed with their knowledge and vision in the area of ​​star formation”. The scientist concludes by thanking the Basal FB210003 project of ANID (Centro de Astrofísica y Tecnologías Afines) that allows him to be part of this international collaboration, called ASHES. Note: This press release is an adaptation and translation of the original published by the National Astronomical Observatory of Japan (NAOJ)