Halo CME MailHalo CME Mail Date: Mon, 20 Oct 2003 19:25 From: Gareth Lawrence Subject: Partial Halo CME on 2003/10/19, frontsided UCMEO 93001 31021 0000/ 31019 61708 90410 1321/ 148// 233// 40458 31019 61642 91722 15608 10484 2112/ 99999 PLAIN BT LASCO and EIT observed a partial halo CME on 2003/10/19. A wide bright loop was first seen in C2 at 17:08 UT in the NE; by 20:30 UT the front spanned ~190 deg from PA 320-150, though faint in the SE. The front first appeared in the NE in C3 images at 18:15 UT and reached its maximal extent by 21:15 UT. The mean plane-of-sky speed was 458 km/s, measured at PA 50 with no compelling evidence for acceleration. The CME was probably associated with a X1.1 X-ray flare which EIT observed between 16:43 - 17:22 UT with peak emission at 17:00 UT. The flare was centered at N08E56. SEC records the flare between 16:29 - 17:04 UT with peak emission at 16:50 UT, from AR 0484 located N08E58. Both an EIT wave and dimming were observed in conjunction with this event. Please note that the apparent change in overall brightness in the EIT movies and images after 17:00 UT is an artifact of the image processing and arises due to a change in exposure time after 17:00 UT. Images and movies are available at ftp://ares.nrl.navy.mil/pub/lasco/halo/20031019 Best wishes, Gareth Lawrence. +----------PLEASE NOTE NEW EMAIL ADDRESS-----------+ Gareth Lawrence, grl@grace.nascom.nasa.gov SOHO-LASCO Operations Scientist, CUA, MC 682.3, Bldg 26, Rm 001, F: +1-301-286-0264 NASA Goddard Space Flight Center, Greenbelt, MD 20771. P: +1-301-286-2941 ++