2008/06/26 by Minho Choi, Kenji Hamaguchi, Jeong-Eun Lee +3 · 2 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/591540
To appear in the Astrophysical Journal
arxiv created 2008/06/26 · openalex publication_date 2008/10/24 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The R CrA region was observed in the 3.5 and 6.2 cm continuum with high angular resolutions (0.6 '' -1.7 '' ). Archival data sets were also analyzed for comparison. IRS 7A showed an enhanced outflow activity recently. The main peak of IRS 7A positionally coincides with an X-ray source, suggesting that the X-ray emission is directly related to the central protostar. The Class 0 source SMA 2 is associated with a double radio source, B9a/b, and seems to be driving two outflows. The B9 complex is probably a multiple-protostar system. IRS 7B is a compact radio source surrounded by an extended structure. The compact source corresponds to the Class 0/I source SMA 1 and is closely associated with an X-ray source, suggesting that magnetic activity starts early in the protostellar stage of evolution. IRS 5 was resolved into two sources, and they display radio flares and X-ray emission, suggesting that energetic magnetic processes are active in both members. The month-scale active phase of IRS 5b implies that the flare activity must involve large-scale magnetic fields. During the strong flare event of IRS 5b in 1998, IRS 5a also showed an enhanced level of emission. This concurrent activity suggests that IRS 5 may be an interacting young binary system. Alternatively, what was seen in the radio images could be a circumbinary halo. The variable radio source B5 was found to be a nonthermal source. Properties of other radio sources, IRS 1, IRS 2, IRS 6, and R CrA, are discussed, and the radio detections of T CrA and WMB 55 are reported. Also presented is the classification of infrared sources based on an infrared color-color diagram.