Radio and X-ray variability of young stellar objects in the Coronet cluster
- Author(s)
- J. Forbrich, Th. Preibisch, K. M. Menten
- Abstract
The Coronet cluster in the nearby R CrA dark cloud offers the rare opportunity to study at least four "class I" protostellar sources as well as one candidate "class 0" source, a Herbig Ae star, and a candidate brown dwarf within a few square arcminutes - most of them detected at radio- and X-ray wavelengths. These sources were observed with the Very Large Array (VLA) at λ = 3.5 cm on nine occasions in 1998, spread over nearly four months. The source IRS 5, shown earlier to emit circularly polarized radio emission, was observed to undergo a flux increase accompanied by changes in its polarization properties. Comparison with VLA measurements taken in January 1997 allows analysis of longer-term variability. In addition to this radio monitoring, we analyze archival Chandra and XMM-Newton X-ray data of these sources. Three class I protostars are bright enough for X-ray spectroscopy, and we perform a variability analysis for these sources, covering a total of 154 ks spread over more than two and a half years. Also in X-rays, IRS 5 shows the most pronounced variability, whilst the other two class I protostars IRS 1 and IRS 2 have more stable emission. X-ray data is also analyzed for the recently identified candidate class 0 source IRS 7E, which shows strong variability as well as for the Herbig Ae star R CrA for which we find extremely hot X-ray-emitting plasma. For IRS 1, 2 and 5, the hydrogen column densities derived from the X-ray spectra are at about half the values derived with near-infrared techniques, a situation similar to what has been observed towards some other young stellar objects.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Max-Planck-Institut für Radioastronomie
- Journal
- Astronomy & Astrophysics
- Volume
- 446
- Pages
- 155-170
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361:20052871
- Publication date
- 01-2006
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103004 Astrophysics
- Keywords
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/b23a6b50-37cd-4d09-a7bd-9fb6f12f2f9c