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Proceedings of the Japan Academy, Ser. B, Physical and Biological Sciences

Vol. 92 No. 2 (2016)

  Vol. 92 No. 2 (2016)
Caption
 
Review
SEEDS — Strategic explorations of exoplanets and disks with the Subaru Telescope —
Motohide TAMURA
Proc. Jpn. Acad., Ser. B, Vol. 92, 45-55 (2016) [Abstract and Full Text]
Original Articles
Concentration of neddylation-related molecules in paranodal myelin of the peripheral nervous system
Hitoshi KAJIGAYA, Tomoko ISHIBASHI, Akiko HAYASHI, Yoshihide YAMAGUCHI and Hiroko BABA
Proc. Jpn. Acad., Ser. B, Vol. 92, 56-68 (2016) [Abstract and Full Text]
Postnatal development of the gastrin-releasing peptide system in the lumbosacral spinal cord controlling male reproductive function in rats
Nao KATAYAMA, Takumi OTI, Keiko TAKANAMI, Tatsuya SAKAMOTO and Hirotaka SAKAMOTO
Proc. Jpn. Acad., Ser. B, Vol. 92, 69-75 (2016) [Abstract and Full Text]
Errata
Errata to “Structure-function correlations of rat trigeminal primary neurons: Emphasis on club-like endings, a vibrissal mechanoreceptor”
Sotatsu TONOMURA, Satomi EBARA, Knarik BAGDASARIAN, Daisuke UTA, Ehud AHISSAR, Inbal MEIR, Ilan LAMPL, Daichi KURODA, Takahiro FURUTA, Hidemasa FURUE and Kenzo KUMAMOTO
Proc. Jpn. Acad., Ser. B, Vol. 92, 76 (2016) [Abstract and Full Text]
Cover Illustration
Unveiling other worlds — direct imaging of exoplanets and disks

  Planets such as Earth and Jupiter are believed to form from the disk-like structures around young stars, protoplanetary disks. The observations of both the planets outside our Solar System or exoplanets and the protoplanetary disks are among the hottest fields in modern astronomy. More than 2,000 confirmed exoplanets have been reported in the last 20 years since its first convincing discovery. However, most of the observations are based on the indirect methods, while the direct imaging of protoplanetary disks is limited to the regions relatively far away from the central star. Therefore, the high-resolution direct imaging of both exoplanets and protoplanetary disks are crucial for this field. Recent advances of direct imaging techniques have enabled the direct imaging observations of exoplanets and protoplanetary disks.
   Motohide Tamura (the author of the paper in this issue, pp. 45-55) and his SEEDS project team have conducted an extensive direct imaging survey of exoplanets and disks using the Subaru Telescope and their self-developed instrument HiCIAO. They have detected four planets or planet candidates and revealed the fine structures of many protoplanetary and debris disks around very young stars. Their detected planets include those around Sun-like stars and a massive star. In particular, as shown in this front figure, the variety of disk structures such as gaps and spiral-arms are clearly detected and this is the first time that such a large number of disks are directly imaged and their detailed structures are revealed. These data have stimulated discussion on the close relationship between the gap/spiral structures and the possible planet including an application of the density wave theory in the protoplanetary disk. Also discussed are the various instability mechanisms such as magneto-rotational instability and secular gravitational instability. Possible presence of planets in the young stars whose ages are only a few mega-years puts a strong constraint on the planet formation mechanisms and challenges to the standard core-accretion model that requires a longer time for the giant planet formation.

Eiichiro Kokubo
National Astronomical Observatory of Japan

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