Observations and analysis of NOAA AR 11429 at KSU-Astronomical Observatory

Journal Article

2013

Published in: Observations and analysis of NOAA AR 11429 at KSU-Astronomical Observatory

al., A. Elmhamdi et . 2013

We study the evolution of the sunspots in the recent super active region NOAA 11429, which spawned a
powerful X5.4/3B flare on March 07, 2012 (2nd on record occurred since 2010), associated with a wide and
fast Coronal Mass Ejection (CME; Halo=070036) and a large proton flux event (6530 p:f :u). The sunspot
group consists a rare example of ‘‘Island Delta’’ in bcd magnetic configuration. This active region dominated
the Solar activities on the northern hemisphere during the period March 03–15, 2012, of the present
Solar Cycle 24, erupting 2 X-class flares, 13 M-class flares, and about 32 C-class flares.
We analyze white-light images, wavelengths around 540 nm, observed at the Astronomical Observatory
of King Saud University (AOKSU). The observations are part of a campaign conducted locally since
early 2012, for monitoring Solar activities on a daily basis. The observations and data reduction are presented
and discussed. We examine the main properties of AR 11429 (i.e. structure, growth and decay) by
computing its daily ‘‘area’’ and ‘‘tilt- & trend-’’ angles, and infer information about its development and
dynamics. The area curve is found to show three distinguishable phases, nicely fitted adopting double-
Gaussian distribution. A close relation between sunspot group area and tilt-angle with the major March
07 powerful flare can be noticed from the current results, that certainly necessitates deep and careful
inspections through studying large sample of events.
The follow-up of the sunspot group the period it inhabits the Solar photosphere, permits exploiting the
proper motion of four long-lived individual spots, as well as tracing the local surface differential rotation,
found to be consistent with empirical results.

• Volume Number: 23
• Magazine \ Newspaper: New Astronomy-Elsevier
• Pages: 73-81