Magnetic properties of x-ray bright points

Abstract

Using high resolution KPNO magnetograms and sequences of simultaneous S-054 soft X-ray solar images we have compared the properties of X-ray bright points (XBP) and ephemeral active regions (ER). All XBP appear on the magnetograms as bipolar features, except for very newly emerged or old and decayed XBP. We find that the separation of the magnetic bipoles increases with the age of the XBP, with an average emergence growth rate of 2.2 ± 0.4 km s−1. The total magnetic flux in a typical XBP living about 8 hr is found to be ≈ 2 x 1019 Mx. A proportionality is found between XBP lifetime and total magnetic flux, equivalent to ≈ 1020 Mx per day of lifetime.