New Subaru Telescope Observations Reveal the Structure of the Outer Solar System
Photo Credits: NAOJ
The Subaru Telescope, in collaboration with the New Horizons spacecraft, recently released exciting survey observations that have the potential to change our understanding of the formation of the solar system, but the end result is only a fraction of the story. Incredibly talented and dedicated team members work around the clock to make these discoveries happen. One of those team members is Dr. Tsuyoshi Terai, a Subaru Support Astronomer, and he is providing some insight into what it takes and what these observations mean to him.
Dr. Terai is in charge of keeping a stable operation of the Hyper Suprime-Cam (HSC). HSC is an integral part of making these observations possible, as it greatly expands the capabilities of the Subaru Telescope. Dr. Terai describes HSC as a “giant mosaic camera with an outstandingly wide field of view nine times larger than the full moon.” The Subaru Telescope is one of the largest telescopes in the world, and with the addition of HSC, its wide-field imaging capabilities are greatly enhanced. Now, astronomers can efficiently search for rare or faint objects from a wide sky coverage and closely investigate their shape, brightness, color, and more.
To successfully operate HSC and maximize research outcomes, Dr. Terai has a laundry list of responsibilities. He prepares, maintains, and troubleshoots instruments for observations with engineers, provides technical support to observers for observation preparation and data analysis, monitors instrument health and performance, develops and updates operation manuals, and supports night observations. Even with all those responsibilities, Dr. Terai still takes his time and says, “I always make a point of doing my best to provide observers with high-quality imaging data as much as possible.”
The observations that were recently announced are the result of an international collaboration that first began in 2004 between the Subaru Telescope and NASA’s New Horizons spacecraft. In this collaboration, the Subaru Telescope uses its wide-field cameras to find outer solar system bodies called Kuiper Belt objects and narrow them down to optimal candidates for the spacecraft to fly by and observe. Dr. Terai specializes in observational studies of small solar system bodies, including Kuiper Belt objects, and among other responsibilities, was involved in developing optimal observation plans to find target candidates. The challenging nature of this work can be further complicated by throwing an international collaboration and limited observation time into the mix, but that doesn’t stop Dr. Terai and the Subaru Telescope team from getting the job done.
“The most challenging part for our team is securing sufficient observation times through several years under high competition. The most rewarding part for me is that I was able to acquire the precious experience of contributing to such a big science project. I think the most important point is in-depth discussion and information sharing among collaboration members.”
It’s often the challenging observations that bring the most joy and excitement to astronomers like Dr. Terai, and this new discovery was no exception. These survey observations reveal that there may be a cluster of Kuiper Belt objects between 70-90 astronomical units (au) from the sun. Previously, most Kuiper objects observed were between 30-55 au, but these new observations have found a valley separating the previously known objects and this potentially new cluster. But what does it mean if these observations are confirmed to be true? Luckily, Dr. Terai can explain this totally unexpected discovery.
“It may indicate that the Kuiper Belt is much larger and more massive than anticipated so far, and it would have significant implications for the size and structure of the protoplanetary disk prior to the planet formation in the initial phase of our solar system. Current models of the solar system’s formation and evolution would need to be updated. Also, it might be able to tell us whether a hypothetical distant planet (“Planet Nine”) really exists or not.”
Dr. Terai believes this result needs further validation, but it’s incredibly exciting to be a part of. The outer edge of the Kuiper belt is the farthest frontier where a spacecraft can travel and observe the oldest objects in our solar system up close, and this discovery has enormous potential to give us an essential clue to the history of the formation and evolution of our solar system. The biggest takeaway that Dr. Terai wants everyone to know is that this discovery could bring us much closer to understanding how Earth was formed as a habitable planet.
The Subaru Telescope team, the New Horizons spacecraft team, and Dr. Terai have already put so much time, effort, and passion into these observations, but for them, the work isn’t over. As they continue, Dr. Terai is looking forward to seeing the whole picture of the Kuiper Belt structure; he says “It would be just like an ancient document that records the 4.6 billion years of our solar system’s history.” Their work contributes to a larger understanding of the universe, and the global effort and cooperation required for these discoveries is an inspiring demonstration of true collaboration. Now New Horizons is traveling further, and the team is eager to see what else is in store.
To learn more about this discovery, click here.
