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Hydrodynamic Pulsation Modes of Multi-frequency Radiative Transfer for Mass-losing Early Type Stars

Research Project

Project/Area Number 14540229
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Astronomy
Research InstitutionTohoku Gakuin University

Principal Investigator

AIKAWA Toshiki  Tohoku Gakuin University, Fac.Liberal Art, Prof., 教養学部, 教授 (10221029)

Project Period (FY) 2002 – 2003
Project Status Completed (Fiscal Year 2003)
Budget Amount *help
¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Keywordsstars / stellar pulsation / radiative transfer / post-AGB stars / chaos / 脈動変光星 / 輻射流体力学 / カオス現象
Research Abstract

Hydrodynamic Pulsation models with an improved radiative transfer is studied. In this study, we concentrated in unified treatment of radiative transfer for linear analysis and non-linear simulation modeling.. As the first step of this study, we took non-diffusion approximation as the approximation of radiative transfer instead of equilibrium diffusion approximation. We have the fallowing results.
1. We constructed computer codes for both linear analysis and non-linear simulation. We may extend the codes for the variable Eddington factor approximation for more improved treatment of radiative transfer. We applied the present codes to post-AGB stars as am example of less-massive supergiants stars as well as classical Cephieds.
2. For linear analysis we compare the pulsation periods and the growth rate of models. The non- equilibrium approximation yields very small change for both the quantities. For non-linear simulation, we compared the time variations of observable quantities at the photosphere of models. The new approximation yields very small changes on these values.
3. We have an interesting result on irregular pulsation of the post-AGB stars. It is known that pulsation model for post-AGB stars shows irregular pulsation fix luminous supergiant stars. The new model yields quite large different time evolution of irregular pulsation compared with ones which is obtained with the model of traditional diffusion approximation for the same values of model parameters. We suspect that the difference comes form the characteristics of chaos. In chaos system, a small change of basic equations may yield great differences of time evolution at later time, even if the calculation starts with the same initial conditions for the same model That is the case of the behavior.

Report

(3 results)
  • 2003 Annual Research Report   Final Research Report Summary
  • 2002 Annual Research Report
  • Research Products

    (8 results)

All 2005 2003 Other

All Journal Article (3 results) Publications (5 results)

  • [Journal Article] 水生植物(マコモ)の年間を通じた窒素・リン吸収量の評価2005

    • Author(s)
      江成敬次郎, 小浜暁子, 玉置智, 山廼辺典夫, 菊地奈美子, 山岸正幸, 藤田光則, 中山正与
    • Journal Title

      環境工学研究論文集 第42巻

      Pages: 469-474

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Journal Article] Computations with a small-size Parallel system : using PVM and MPI2003

    • Author(s)
      Toshiki Aikawa, Syouji Sato
    • Journal Title

      Journal of Human Informatics (Tohoku Gakuin Univ.) 8

      Pages: 85-98

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Journal Article] Linear and nonlinear pulsation models using unified Treatment of radiative transfer : I. non-equilibrium Diffusion approximation

    • Author(s)
      Toshiki Aikawa
    • Journal Title

      Astronomy & Astrophysics (to be submitted)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2003 Final Research Report Summary
  • [Publications] T.Aikawa: "The Wigner distribution for pulsation behaviors in post-AGB"Proceeding in "Mass-losing pulsating stars and their circumstellar matter". 115-116 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] 相川利樹, 佐藤昭治: "小規模並列システムによる計算:PVM/.MPIを使ってみて"人間情報学研究(東北学院大学). 8巻. 85-98 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] 相川利樹: "輻射流体脈動モデルに現れるストレンジモード"連星/変光星ワークショップ2003集録. 53-56 (2004)

    • Related Report
      2003 Annual Research Report
  • [Publications] T.Aikawa: "The Wigner distribution for pulsation behaviors in post-AGB"Proceeding in "Mass-losing pulsating stars and their circumstellar Matter". (In press).

    • Related Report
      2002 Annual Research Report
  • [Publications] 相川利樹, 佐藤昭治: "小規模並列システムによる計算: PVM, MPIを使ってみて"人間情報学研究(東北学院大学). (印刷中).

    • Related Report
      2002 Annual Research Report

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Published: 2002-04-01   Modified: 2016-04-21  

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