An international research team led by Jeong-Eun Lee, a professor at Seoul National University, used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the triple protostar system IRAS 04239+2436, to investigate the detailed structure of the gas around the protostars. As a result, they detected radio waves emitted by sulfur monoxide (SO) molecules that indicate the presence of shockwaves and discovered that their distribution forms three large spiral arms. By comparing the velocity of the gas obtained from the observations with numerical simulations led by Tomoaki Matsumoto, a professor at Hosei University, they found that the three spiral arms also play a role of “streamers” feeding materials to the three protostars. Although the origin of the streamers has been unclear, the combination of observations and simulations reveals, for the first time, how the streamers form in the dynamical process of multiple star formation.
This research was presented in a paper "Triple spiral arms of a triple protostar system imaged in molecular lines" by Jeong-Eun Lee et al. in the Astrophysical Journal on August 4, 2023. (August 4, 2023 Press Release)