Associate Prof. Takashi Miyata, Institute of Astronomy
Infrared astronomy, Research and development of observation equipment What we observe at our laboratory are solid particles in the universe that are commonly called “dust.” The image of the universe many people have, I suppose, is that of a vast outer space filled with stars — something like a starry sky. In fact, mixed in among these stars, the universe is believed to be filled with a lot of gas, solid particles, sand granules, and something like smoke. When you look at the Milky Way, you see many stars. In the middle of the Milky Way, a black line can be seen, where dust-like particles absorb light. This is how we know that there’s a lot of dust in the Milky Way, where we live. And such dust is also distributed widely throughout the universe in other galaxies. What does dust teach us? Where did this dust come from? Stars are born in dark nebulae and other types of clouds, and a star such as our Sun shines and then starts to die off. The death of a star does not mean its existence is over. Materials necessary for the birth of next generations of stars are hurled out from these dying stars. When stars die, the materials that were once amassed and fused to make them are returned into space. Dust is scattered out from stars when they die. Thus unless we study this dust, it will be impossible for us to understand how cosmic matter changes. Observing mid-infrared radiation from the ground The mid-infrared radiation that we’re observing is light about 30 μm in wavelength. By using mid-infrared radiation, we think we’ll be able to get a better understanding of how much dust exists around a particular star. The MAX38 is a camera we have developed. It’s the only camera that can catch a 30-μm band of light from the ground, and it’s going to be attached onto the University of Tokyo’s 1-m telescope. Atacama, where the telescope has been installed, is located just on the opposite side of the Earth from Japan. The University of Tokyo Atacama Observatory (TAO), located 5,640 meters above sea level, is the world’s highest observatory. Setting up a telescope at an altitude of 5,640 meters was extremely challenging. When we first started the project, there weren’t even animal trails around the site. We had to build roads to transport all the equipment necessary to set up the telescope. I think TAO is an observation station the University of Tokyo made almost entirely through its own efforts. Unique science in the world One of the astral bodies we have found is NGC6302, which is commonly called the Butterfly Nebula. Seen from photographs, it looks like a beautiful butterfly with its wings spread open. But what is important is not the wings, but the body that can be seen at the center of the picture. We can see something that looks like a black strip there. We believe that it appears black because dust is blocking the light in that area, where dust has accumulated after being blown out from stars when they died. But we still don’t know how much dust is in fact there and what the ratio for the amounts of dust in the body and the wings might be. When we made 30-μm observations of the Butterfly Nebula, we were able to catch additional light in the middle of the nebula quite clearly. It was the first time we found out this clearly that there was that amount of light. The MAX38 produced very significant results by demonstrating for the first time that astronomy was able to achieve observations at the 30-μm wavelength from a ground-based telescope. And we have developed more equipment, called MIMIZUKU, that advances our observational capabilities further. The MIMIZUKU will be attached to a 6.5-m telescope, which is scheduled to be set up where the 1-m telescope is located. By using the 6.5-m telescope, we’ll be able to gather 30 times more light than with the 1-m telescope. Since the resolution is also expected to be about 6 times clearer than it is now, I’m sure that the equipment will enable us to do unique science that cannot possibly be done elsewhere. Miyata Group does EVERYTHING. The standout feature of our group is that we do everything on our own ― from preparing necessary equipment to conducting observations. Since it’s not always the case that products available on the marketplace are better than hand-made ones when it comes to observing infrared rays and mid-infrared radiation, we make our own cameras. As a result, we can collect data that nobody has ever obtained, and can catch images that nobody has ever seen. When we succeed in collecting such data, we get very excited, which becomes the motivating force, as well as the fun, of our research.