Coronal structure at the total solar eclipse 2009-07-22

Abstract

Solar corona is the outermost part of the solar atmosphere, from which strong UV and X-ray radiation are emitted. Coronal high temperature plasma outflows and forms the solar wind. Coronal activities influence seriously the space environment between the Sun and the Earth. Coronal structures are closely related with the solar activities. The total solar eclipse at the July 22, 2009, is the best magnificent sight in the 21st century and the best opportunity to observe the corona on ground. However, due to bad weather, most observations in the total eclipse areas were baffled. Fortu-nately, some images of high quality were taken in a few places with good weather. In this work, a series of images are selected and digital processing is made with the computer. Studying them together with the images of outer corona by SOHO satellite/LASCO C2 at that day, some coronal structures are revealed and radial brightness profiles of the corona in directions of pole and equator of the Sun are measured. The solar cycle 24 began in 2009 and a few sunspots ap-peared. At this eclipse, coronal structures show more extents in equatorial regions than in polar regions, with differ-ences between east and west and between south and north of the solar disk. Coronal streamers on east of the disk, par-ticularly the largest one in north of the equator are very obvious. Polar rays are more in south polar region than in north polar region. The radial brightness profiles of the corona in directions of pole and equator are rather similar to those at the total eclipse in 2008 and those of the Van de Hulst model in solar minimum. Some features are also shown in the isophote map of the corona.