Astronomy and Astrophysics – Astronomy
Scientific paper
May 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002aas...200.7006h&link_type=abstract
American Astronomical Society, 200th AAS Meeting, #70.06; Bulletin of the American Astronomical Society, Vol. 34, p.759
Astronomy and Astrophysics
Astronomy
Scientific paper
We report the analyses of the young magnetic B star ρ Oph S1 (hereafter S1) observed twice with the Chandra X-ray observatory for about 100 ksec each. ρ Oph S1 is a highly embedded young star with the magnetosphere, associated with the ρ Ophiuchi cloud core A, and a candidate of young magnetic chemically peculiar(CP) stars. It may fill the gap between pre-main-sequence(PMS) stars and main-sequence(MS) stars and is thus important for studying the evolution of stellar X-ray activity. With Chandra, the X-ray emission is detected in both observations. The average flux is almost the same between the observations, but, in each observation, it shows significant time variations by a factor of two. Each spectrum is reproduced with an absorbed power law model or thin-thermal plasma model of ~ 2keV with extreme low metal abundance (less than 0.1 solar). The spectrum in the first observation seems to have an excess above 6 keV, which might correspond to highly ionized iron, whereas the spectrum in the second observation shows an anomalous absorption edge at ~ 4 keV. If the X-ray emission is thermal, the log LX/Lbol ratio or the plasma temperature is similar to magnetic CP stars (He strong stars) and intermediate mass PMSs. This supports S1 as a young magnetic CP star. In this case, however, S1 might need to have a mechanism to select elements in the atmosphere, which is generally seen on CP stars. If it is nonthermal, the X-rays might originate from nonthermal bremsstrahlung emission like solar hard X-ray flares, produced by the collision of infalling materials on the surface. A plausible structure of the emitting region is also discussed, including the interpretation of the edge like feature. Acknowledgement: This research is supported by the National Space Developmen Agency of Japan and the National Research Council.
Hamaguchi Kenji
Kyoto University Cosmic Ray Group Collaboration
NASA/GSFC/LHEA Collaboration
No associations
LandOfFree
Chandra observations of a young embedded magnetic B star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Chandra observations of a young embedded magnetic B star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chandra observations of a young embedded magnetic B star will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1720102