Study of optical processes in the atmospheres of exoplanets and their feasibility of observations

2012 Fiscal Year Final Research Report

• Project/Area Number: 23654065
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: Hokkaido University
• Principal Investigator: YAMAMOTO Tetsuo 北海道大学, 低温科学研究所, 教授 (10126196)
• Co-Investigator(Kenkyū-buntansha): NAKAMOTO Taishi 東京工業大学, 大学院・理工学研究科, 准教授 (60261757)
• Project Period (FY): 2011 – 2012
• Keywords: 系外惑星 / 光赤外線天文学 / 惑星科学

Research Abstract

We formulated light propagation in the atmospheres of exoplanets in transit and derived a formula of an angle of refraction for light rays propagating through the atmosphere. The formula provides precise values even for the rays incident with small impact parameters onto the atmosphere. We proposed a method of estimating a scale height of an atmosphere from a light curve at a transition of an exoplanet in front of a central star. Systematic calculations of ray tracing are carried out for the rays passing through model atmospheres under isothermal hydrostatic equilibrium with varying wavelength of the light rays, and discussion was made on apparent increase in the radius of a planet in transition. The results are applied to the observation of Galilean satellites, which are observed through the atmosphere of Jupiter. Analysis of the observation indicates that the theory roughly explains the observation but suggests the presence of some effect that is not taken into account in the theory.

Research Products

• [Journal Article] Evaporation of Icy Planetesimals due to Bow Shocks (2013)
  • Author(s): Tanaka, K.K., Yamamoto, T., Tanaka, H., Miura, H., Nagasawa, M., and Nakamoto, T.
  • Journal Title: Astrophyscal Journal, 2013 Volume: 764 Pages: 120-130
  • DOI: doi:10.1088/0004-637X/764/2/120
  • Peer Reviewed
• [Journal Article] 微小重力と惑星科学 (2012)
  • Author(s): 山本哲生
  • Journal Title: JASMA Volume: 28 Pages: 161-162
  • URL: http://www.e-jasma.com/index.html
• [Journal Article] Effects of Atmospheric Absorption of Incoming Radiation on Radiation Limit of the Troposphere (2012)
  • Author(s): Kurokawa, H. and Nakamoto, T.
  • Journal Title: Journal of the Atmospheric Sciences Volume: 69 Pages: 403-413
  • DOI: doi:10.1088/0004-637X/738/2/141
  • Peer Reviewed
• [Journal Article] Effect of Photodesorption on Snow Line at the Surface of Optically Thick Circumstellar Disks around Herbig Ae/Be Stars (2012)
  • Author(s): Oka, A., Inoue, A. K., Nakamoto, T., and Honda, M.
  • Journal Title: Astrophysical Journal Volume: 747 Pages: 138-149
  • DOI: doi:10.1088/0004-637X/747/2/138
  • Peer Reviewed
• [Journal Article] Sublimation temperature of circumstellar dust particles and its importance for dust ring formation Earth (2011)
  • Author(s): Kobayashi, H., Kimura, H., Watanabe, Yamamoto, T., and Muller, S.
  • Journal Title: Planets, Space Volume: 63 Pages: 1-9
  • DOI: doi:10.5047/eps/2011.03.012
  • Peer Reviewed
• [Journal Article] The Direct Stellar Radiation Pressure at the Dust Sublimation Front in the MassiveStar Formation: Effects of Dust-Free Disk (2011)
  • Author(s): Tanaka, K. E. I. and Nakamoto, T.
  • Journal Title: Astrophysical Journal Volume: 739 Pages: L50-L53
  • DOI: doi:10.1088/2041-8205/739/2/L50
  • Peer Reviewed
• [Journal Article] Evolution of Snow Line in Optically Thick Protoplanetary Disks: Effects of Water Ice Opacity and Dust Grain Size (2011)
  • Author(s): Oka, A., Nakamoto, T., and Ida, S.
  • Journal Title: Astrophysical Journal Volume: 738 Pages: 141-151
  • DOI: doi:10.1088/0004-673X/738/2/141
  • Peer Reviewed
• [Journal Article] The Rebound Condition of Dust Aggregates Revealed by Numerical Simulation on Their Collisions (2011)
  • Author(s): Wada, K., Tanaka, H., Suyama, T., Kimura, H., and Yamamoto, T.
  • Journal Title: Astrophysical Journal Volume: 737 Pages: 36-48
  • DOI: doi:10.1088/0004-673X/737/1/36
  • Peer Reviewed
• [Presentation] Possible Inhomogeneity Inside of Asteroids (2012)
  • Author(s): Nakamoto, T.
  • Organizer: Asteroids, Comets, Meteors
  • Place of Presentation: 朱鷺メッセ,新潟
  • Year and Date: 2012-05-17
• [Presentation] A Correlation among Shape, Composition, and Texture of Cosmic Spherules (2012)
  • Author(s): Nakamoto, T., Doi, M., Nakamura, T., and Yamauchi, Y.
  • Organizer: European Geosciences Union
  • Place of Presentation: Austria Center Vienna,オーストリア
  • Year and Date: 2012-04-27
• [Presentation] Refraction of Light in Exoplanet Atmosphere (2011)
  • Author(s): Nakamoto, T. and Yamamoto, T.
  • Organizer: The First Kepler Science Conference
  • Place of Presentation: NASA Ames Research Center, California, USA.
  • Year and Date: 20111205-09
• [Presentation] 原始惑星系円盤内スノーラインの進化と微惑星の組成 (2011)
  • Author(s): 中本泰史
  • Organizer: GCOE地球から地球たちへ全体研究発表会2011
  • Place of Presentation: 東京大学・本郷
  • Year and Date: 2011-11-23
• [Presentation] Planetesimal Evaporation due to Planetesimal Bow Shock (2011)
  • Author(s): Yamamoto, T.
  • Organizer: AOGS 2011
  • Place of Presentation: Convention Center, Taipei International Convention Center,台湾.
  • Year and Date: 2011-08-09
• [Remarks]
  • URL: http://risu.lowtem.hokudai.ac.jp/index.html
• [Remarks]
  • URL: http://www.geo.titech.ac.jp/lab/nakamoto/activities/activities-j-11.html