The multinational ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP) team has discovered a young quadruple star system within a star-forming area in the Orion constellation, which was a surprise discovery. The discovery was made while using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to investigate 72 dense cores in the Orion Giant Molecular Clouds (GMCs). These findings offer a compelling explanation for the origins and mechanics of binary and multiple-star systems.
Prof. Liu Tie of the Shanghai Astronomical Observatory (CAS-SHAO) led the team. Researchers from the CAS-SHAO, the School of Astronomy and Space Science (CAS-SASS), the NRC Herzberg Astronomy and Astrophysics, the National Astronomical Observatory of Japan (NAOJ), the Max Planck Institute for Astronomy (MPIA), the Korea Astronomy and Space Science Institute (KASI), the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), the National Science Foundation’s NOIRLab’s International Gemini Observatory,
Astronomers and astrophysicists are well aware that nearly half of the stars in the Milky Way are in binary systems. Understanding galactic development, planetary formation, and the emergence of life requires an understanding of how multiple star systems form. According to the most widely accepted hypothesis of star formation (the Nebular Hypothesis), stars develop in the densest parts of molecular clouds (also known as the “dense core”). While this theory adequately accounts for individual star systems, the factors that drive the creation of multi-star systems are yet unknown.
Multiple star systems are currently thought to emerge by the fragmentation of cloud cores during their early history, however observations are historically limited. To solve this riddle, the ALMASOP team looked for thermal emissions with a wavelength of 1.3 mm – in the extremely high frequency (EHF) region – in 72 youthful and cold cores in the GMCs of the Orion constellation.
They discovered a system of four star objects while observing a dense cold core in Orion B GMC around 1,500 light-years from Earth (designated G206.93-16.61E2).
These consisted of two protostars and two gas concentrations that are anticipated to collide in the near future due to gravitational collapse. They also discovered that the greatest distance between the four objects in the system was roughly 1,000 Astronomical Units (AUs), which is more than 33 times the distance between the Sun and Neptune (30 AUs). This is in contrast to the last time a quadruple system was observed by an international team using ALMA in 2015. The finding team saw a newborn protostar and three gravitationally locked dense gas clouds that will generate new stars in 40,000 years.
However, in that scenario, the quadruple system detected had a much higher separation than 1,000 Astronomical Units (AUs). The dust emission spectra also revealed multiple elongated ribbon-like structures that connected and stretched outwards from the four objects. To figure out what role these structures played, the researchers ran a computer simulation that compared a comparable quadruple system to the one they observed. The team hypothesizes that these extended ribbons are “funnels” that transfer gas from the core’s outer envelope to the protesters and connect nascent stars based on the findings.
According to Luo Qiu-yi, a Ph.D. student at SHAO and the study’s first author:
“This system’s exceptional compactness and close proximity is a fascinating discovery.” According to the analysis, this system is quite likely to create a gravitationally bound quadruple star system in the future. We don’t know how the gas outflows spread since they could be intertwined with the gas accretion processes of system members. This research focuses on the complex interactions between members of a growing higher-order star system.”
“The simulation supports the idea that these ribbons can serve as large-scale accretion streamers,” Prof. Liu noted. “As a result of the feeding of these continuum ribbons, the two gas condensations in the system have the potential to form a star.” The accretion streamers may also fragment, resulting in the formation of new stars.”
Finally, the observations revealed complex gas outflows caused by stellar winds generated by the system’s protostars, causing some of the accreting gas and dust to be lost. This could have an impact on the evolution of this system, similar to what has been found near Active Galactic Nuclei (AGNs), where winds generated by the Supermassive Black Hole (SMBH) drive material out of the galactic center. Scientists believe that future studies utilizing ALMA and other millimeter/submillimeter telescopes will disclose more data about multi-star systems in the creation process.
SOURCE:Chinese Academy of Sciences
