Hard X-Ray Emissions from Protostar Candidates
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.
KeywordsMolecular Cloud Tauri Star Dark Cloud Cloud Center Soft Band
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- Zinnecker, H. and Preibisch, T. H. (1994) Astronomy and Astrophsics Google Scholar