Osaka Metropolitan University researchers discovered “baby stars” in the Small Magellanic Cloud, an environment similar to the early universe. They discovered molecular outflow near one of the baby stars, which has properties similar to those seen in the Milky Way galaxy, providing a new perspective on star formation.
The heavy elements in interstellar matter have a significant impact on the star formation mechanism. Because there was not enough time for nucleosynthesis to produce heavy elements in stars in the early universe, the abundance of heavy elements was lower than in the present universe. It is not well understood how star formation in such an environment differs from star formation today.
The Atacama Large Millimeter/submillimeter Array (ALMA) was used by an international team led by Professor Toshikazu Onishi of Osaka Metropolitan University and Project Assistant Professor KazukiTokuda of Kyushu University/NAOJ to observe high-mass young stellar objects in the Small Magellanic Cloud.
The Small Magellanic Cloud, like galaxies 10 billion years ago, has a low abundance of elements heavier than helium. Because of its close proximity to the Earth, the target provides a detailed observational view. Researchers detected a bipolar gas stream flowing out of the “baby star” Y246 in their study, which was published in The Astrophysical Journal Letters, and determined that the molecular flow has a velocity of more than 54,000 km/h in both directions.
Growing “baby stars” in the present universe are thought to have their rotational motion suppressed by this molecular outflow during gravitational contraction, accelerating star growth. The discovery of the same phenomenon in the Small Magellanic Cloud implies that this process of star formation has occurred frequently over the last 10 billion years. The team also anticipates that this discovery will open up new avenues for research into star and planet formation.