RT Journal Article
SR Electronic
T1 X-ray Emissions from Comets Detected in the Röntgen X-ray Satellite All-Sky Survey
JF Science
JO Science
FD American Association for the Advancement of Science
SP 1625
OP 1630
DO 10.1126/science.277.5332.1625
VO 277
IS 5332
A1 Dennerl, Konrad
A1 Englhauser, Jakob
A1 Trümper, Joachim
YR 1997
UL http://science.sciencemag.org/content/277/5332/1625.abstract
AB After the unexpected discovery of x-rays emitted from comet C/1996 B2 (Hyakutake) with the Röntgen X-ray Satellite (ROSAT) in March 1996, x-ray emissions from comets C/1990 K1 (Levy), C/1990 N1 (Tsuchiya-Kiuchi), 45P (Honda–Mrkos–Pajdušáková), and C/1991 A2 (Arai), optically 300 to 30,000 times fainter than Hyakutake, were discovered in archival ROSAT data. These findings establish comets as a class of x-ray sources and allow their properties to be studied over a wide optical brightness range. The results indicate that charge exchange between highly charged heavy ions in the solar wind and cometary neutrals is the dominant process for the x-ray emission. Comets may thus be used as probes for monitoring the heavy-ion content of the solar wind.