New Frontiers of Extrasolar Planets: Exploring Terrestrial Planets

Grant-in-Aid for Scientific Research by the Ministry of Education, Culture, Sports, Science and Technology  Scientific Research on Innovative Areas (Research in a proposed research area) 2011-2015

Home > Researcher Columns > Where did we come from? What are we? Where are we going?

Where did we come from? What are we? Where are we going?

Paul Gauguin expresses in his paintings the topics of the questions which human beings with intelligence have been seeking the answers of for over few thousand years. Finally, we are getting closer to the scientific answers to these questions.

In 1995, observations indicated that there were also extrasolar planets around fixed stars other than the Sun. There is a heavy gas giant similar to Jupiter. It is located near the central star inside the orbit of Mercury if we put it in solar system. It completes its orbit around the central star in 4 days.

The research of extrasolar planets has begun all over the world. Research includes the existence of terrestrial planets, habitable planets, and the verification of any life on these planets. Extrasolar planets will be incorporated into the main scientific fields of natural science, including astronomy, planetary science and biology.

Although people may not make the distinction between astronomy and planetary science, there is a big difference between its methods, and it is often difficult for the researchers from each side to have discussion, but we are no longer in the situation to precisely divide astronomy and planetary science. There is a new researching category called extrasolar planets to get rid of their boundaries. The researchers still tend to pick a side, but it is important to strengthen the linkage between them to research this new category "extrasolar planet" together.

There are four main plans in the research of extrasolar planets. We aim to inspect the terrestrial and jovian planets in a habitable zone* as well as we directly radiograph the Jovian planet to investigate the characteristics of its atmosphere by using spectroscope. We also encourage high-resolution observation of protoplanetary disk as the birthplace of planets. By fusing these observations and theoretical researches of planetary formation and planetary atmosphere, we understand more about the origin and formation/ evolution of the terrestrial and Jovian planet including the planets in solar system. We believe that we can take a big step for understanding the origin of the planetary system and the birth with this area of research.

(Representative: Masahiko Hayashi)

*Habitable Zone
The region around a planet where atmospheric pressure and temperature make it possible to maintain liquid water. Liquid water is important to life when considering the planet with an orbit in a certain distance from the primary star. For example, in our solar system, Earth is positioned in the habitable zone, thus maintaining liquid water. On Venus, water only exists as vapor because it is out of the habitable zone.