The majority of sun-like stars originate with other stars in multi-star systems. Therefore, a general theory of star formation must consider the formation of multi-star systems. However, astronomers are still determining the creation scenario due to the complexity and lack of high-resolution, high-sensitivity evidence.
Recent observations of protostars, in particular, have frequently noted formations known as “streamers” of gas flows toward the protostars, although it is not yet known how these streamers develop.
Using the Atacama Large Millimeter/submillimeter Array (ALMA), an international team observed three spiral arms of gas-feeding material to three protostars forming in a trinary system, which has clarified the formation of multi-star systems. The team found that emissions from sulfur monoxide (SO) molecules trace three spiral arms around the three protostars forming in the system.
Numerical magnetohydrodynamic simulations, which show that the enormous arms only occur in magnetically weak clouds, complement the observational observations. The enormous triple spiral arms may have formed due to gravitational interactions between compact triple protostars and the turbulent infalling envelope, according to numerical simulations.
For the first time, the combination of observations and simulations showed how the streamers are produced and how they aid in developing the protostars at the center.
Journal Reference:
- Jeong-Eun Lee et al., Triple Spiral Arms of a Triple Protostar System Imaged in Molecular Lines, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/acdd5b