Wide-field far-infrared image of the Small Magellanic Cloud obtained with the Herschel Space Observatory (left). ALMA image of the molecular outflow from the baby star Y246 (right). Cyan and red colors show the blueshifted and redshifted gas, respectively, observed in carbon monoxide emission. The cross indicates the position of the baby star.
Credit: ALMA (ESO/NAOJ/NRAO), Tokuda et al., ESA/Herschel
The heavy elements in interstellar matter significantly impact the mechanism of star formation. In the early universe, the abundance of heavy elements was lower than in the present universe because there was not enough time for nucleosynthesis to produce heavy elements in stars. It has not been well understood how star formation in such an environment differs from present-day star formation.
An international team led by Kazuki Tokuda, Project Assistant Professor at Kyushu University/NAOJ, has conducted ALMA observations toward massive young stellar objects in the Small Magellanic Cloud, which is characterized by a low abundance of elements heavier than helium, similar to the galaxies 10 billion years ago. The target provides a detailed observational view thanks to the relatively close distance from the earth. In this study, researchers detected a bipolar gas stream flowing out of the “baby star” Y246 and determined that the molecular flow has a velocity of more than 54,000 km/h in both directions.
In the present universe, growing “baby stars” are thought to have their rotational motion suppressed by this molecular outflow during gravitational contraction, accelerating the star growth. The discovery of the same phenomenon in the Small Magellanic Cloud suggests that this process of star formation has been common throughout the past 10 billion years. The team also expects this discovery to bring new perspectives to studying stars and planet formation.
Additional information
These research results have been published as K. Tokuda et al. “The First Detection of a Protostellar CO Outflow in the Small Magellanic Cloud with ALMA,” in the Astrophysical Journal (DOI: 10.3847/2041-8213/ac81c1).
This work was supported by JSPS Grants-in-Aid for Scientific Research (JP18H05440, JP19K14760, JP21H00049, JP21H00058, JP21H01145, and JP21K13962) and the ALMA Joint Scientific Research Project (2022-22B).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
