Orientation of X-Ray Bright Points in the Quiet Sun

Abstract

Thanks to the high-resolution images from the X-ray telescope (XRT) aboard the Hinode satellite, X-ray bright points (XBPs) in the quiet region of the Sun are resolved and can be seen to have complex loop-like structures. We measure the orientation of such loop structures for 488 XBPs picked up in 26 snapshot X-ray images near the disk center. The distribution of the orientation is slightly but clearly biased to the east – west direction: the random distribution is rejected with a significance level of 1% by the χ 2-test. The distribution is similar to the orientation distribution for the bipolar magnetic fields. The XBP orientation is, however, much more random than that of the bipolar magnetic fields with similar size. 24% of the XBPs are due to emerging bipoles, while the remaining 76% are due to chance encounters of opposite polarities.