Variation of the X‐Ray Bright Point Number over the Solar Activity Cycle

Abstract

X-ray bright points (XBPs) have been counted from Yohkoh/Soft X-ray Telescope (SXT) images obtained during the period from 1992 December to 1997 August. The number of XBPs did not change significantly until about 1995. It then varied inversely with the sunspot number and reached a maximum during the solar minimum. However, taking into account both the XBP's intensity histogram and the background coronal intensity histogram, it seems that the apparent observed increase of XBP number near the solar minimum is due to a decrease of the background intensity, not due to an actual increase. There appears to be little correlation between XBP and sunspot numbers. (C) 2000 COSPAR. Published by Elsevier Science Ltd.