Through multi-wavelength observations using the Subaru Telescope and other telescopes, the signs of stellar objects that have flown by young star systems and disrupted their protoplanetary disks have been revealed. This study represents the first comprehensive investigation into how “intruders” into a star system interact with its protoplanetary disk. The findings provide important insights into the history of our solar system.
This object-orbiting event was discovered in a young binary star system, Z Star Canis Major (Z CMa), about 3700 light-years away from Earth (Figure 1). Infrared observations with the Subaru Telescope and other telescopes have revealed a protoplanetary disk surrounding the binary system and an elongated tail-like structure within it (Hawaii Observatory 2016 Observation Results).The ALMA telescope has discovered a new object at the end of this “tail,” about 5000 astronomical units (5000 times the distance between the Sun and Earth) from the binary star.
When celestial bodies encounter each other, they cause vortices, distortions, gaps, and other changes in the disk’s morphology that can be seen as traces of the flyby. By carefully observing the disk of Z CMa, scientists have identified multiple traces of the flyby.
These traces not only helped to validate the celestial flyby, but also led us to consider what the “visit” might mean for the future of Z CMa and the planets born in that system. Flyby events can dramatically alter the protoplanetary disk, the cradle of planetary birth, just as a long “tail” was created around Z CMa. Another possible effect on the central star is the known explosive brightening of the central star in Z CMa due to the sudden outpouring of gas from the disk, which may have been facilitated by the disturbance of the disk by the flying object. As a result, the development of the entire star system may also be affected in ways that have not yet been observed.
Dr. Ruobing Dong (University of Victoria), who led the study, noted that studying the evolution and growth of young star systems throughout the galaxy will also help us better understand the origin of our solar system. Studying these events gives us an insight into the past history of how our solar system developed,” he said. Seeing these events occur in newly formed systems gives us the information we need to say, ‘Oh, this could have happened a long time ago in our solar system.’
Z CMa has long attracted attention as a mysterious variable-light object, but we were surprised to see it in this form,” says co-researcher Professor Motohide Tamura (University of Tokyo/National Institutes of Natural Sciences, Center for Astrobiology). The sharp observations by Subaru, ALMA, and VLA at multiple wavelengths, combined with the latest theoretical research, enabled us to successfully capture this unusual flyby phenomenon that occurred on a newly born star.
For more information, please refer to the Press release article from the National Radio Astronomy Observatory (NRAO).
This research result was published in Nature Astronomy on January 13, 2022 (Ruobing Dong et al. “A likely flyby of binary protostar Z CMa caught in action“)。
About Subaru Telescope
Subaru Telescope is a large optical-infrared telescope operated by the National Astronomical Observatory of Japan (NAOJ) and supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) under the Large-Scale Scientific Frontier Initiative. Mauna Kea, where Subaru Telescope is located, is a precious natural environment and an important place in Hawaiian culture and history, and we are deeply grateful for the opportunity to explore the universe from Mauna Kea.
■Related Links
- ALMA catches “intruder” redhanded in rarely detected stellar flyby event (NRAO 13 Jan 2022, Press Release)
- Subaru Telescope January 13, 2022 Press Release
