(Sen) - The Sun is becoming increasingly active as it heads towards the maximum of the eleven year solar cycle in 2013, and two powerful solar flares have erupted so far this month.
The first flare erupted from the limb of the solar disc in active region 1515 on 6 July, and was classed as an X 1.1 flare. X-class flares are the most powerful type of solar flares, with M-class being slightly less powerful.
On 12 July, an X 1.4 flare was emitted from active region 1520, which first rotated into view on 6 July. The active region of sunspots stretched for around 300,000 kilometres across the solar surface. There was also a coronal mass ejection (CME) associated with the flare. The CMEs are much larger eruptions than the localised flares, and move towards Earth at a slower speed than the flares.
CMEs can impact the technological infrastructure on Earth, such as power generation as well as satellite functions in orbit. Their arrival also produces aurora and astronomers have been on alert to search for and photograph the dancing green glows.
The Solar Terrestrial Relations Observatory (STEREO) B spacecraft measured the speed of the CME travelling to Earth to be around 1350 kilometres per second. The particles from the CME hit the Earth’s atmosphere on the night of 14 July, and aurorae were reported at high latitudes.
The image shows the Sun as seen by NASA’s Solar Dynamics Observatory (SDO) on 12 July shortly before the X 1.4 flare was released. The picture combines a set of observations known as magnetogram with light at a wavelength of 171 Angstroms. The magnetogram highlights magnetic field lines on the Sun, and assists scientists in understanding the dynamics of the solar magnetic field prior to an outburst. The light at 171 Angstroms is used to emphasise the giant loops of material emanating from active region 1520.
The 12 July flare is the sixth X-class flare of 2012, and it is likely that there will be many more to come.