Hard X-Ray Emissions from Protostar Candidates

  • K. Koyama
  • Y. Tsuboi
  • S. Ueno


We have carried out a systematic survey of hard X-rays from the core of molecular clouds with the ASCA satellite and discovered hard X-rays from protostar candidates (class I objects) in the cores of the dark clouds R CrA and ρ Oph. The X-ray spectra of protostars have higher temperatures and larger absorptions than those of T Tauri Stars (TTSs). The protostars exhibited flare-like activity with the fast rise and slow decay, which is similar to TTSs. The temperature increases rapidly and decreased gradually. We found striking feature in the X-ray spectrum of Rl: unusually flat spectrum and two emission lines at 6.2 and 6.9 keV. Possibly the unusual hard X-ray spectrum have close connection to the jet-like radio structure.


Molecular Cloud Tauri Star Dark Cloud Cloud Center Soft Band 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • K. Koyama
    • 1
  • Y. Tsuboi
    • 1
  • S. Ueno
    • 1
  1. 1.Department of PhysicsKyoto UniversitySakyo-kuJapan

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