TY - JOUR
T1 - Discovery of hard X-rays from a cluster of protostars
AU - Koyama, Katsuji
AU - Hamaguchi, Kenji
AU - Ueno, Shiro
AU - Kobayashi, Naoto
AU - Feigelson, Eric D.
PY - 1996
Y1 - 1996
N2 - We report on the detection of hard X-rays from protostar candidates (Class I sources) in the R Coronae Australia (R CrA) molecular cloud. The hard X-rays are found even in the quiescent states with extremely high temperature of about 6 keV. One of the sources, probably the embedded far-infrared source R1, exhibited a powerful X-ray flare. These phenomena are similar to, but with a significantly higher temperature than, those seen in T Tauri stars. The flare spectrum is unusual, showing a broadened or double emission-line structure between 6.2 and 6.8 keV. Since X-rays are unexpected from current protostellar theory, these ASCA observations should have a significant impact on our understanding of star formation and the earliest phases of stellar evolution.
AB - We report on the detection of hard X-rays from protostar candidates (Class I sources) in the R Coronae Australia (R CrA) molecular cloud. The hard X-rays are found even in the quiescent states with extremely high temperature of about 6 keV. One of the sources, probably the embedded far-infrared source R1, exhibited a powerful X-ray flare. These phenomena are similar to, but with a significantly higher temperature than, those seen in T Tauri stars. The flare spectrum is unusual, showing a broadened or double emission-line structure between 6.2 and 6.8 keV. Since X-rays are unexpected from current protostellar theory, these ASCA observations should have a significant impact on our understanding of star formation and the earliest phases of stellar evolution.
UR - http://www.scopus.com/inward/record.url?scp=0030300541&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030300541&partnerID=8YFLogxK
U2 - 10.1093/pasj/48.5.L87
DO - 10.1093/pasj/48.5.L87
M3 - Article
AN - SCOPUS:0030300541
SN - 0004-6264
VL - 48
SP - L87-L92
JO - Publications of the Astronomical Society of Japan
JF - Publications of the Astronomical Society of Japan
IS - 5
ER -