APOD 2.3

Orange Sun Scintillating

The photograph above was captured using Hydrogen Alpha(usually the brightest wavelength of light in stellar astronomy), so it is falsely colored.  There are many spicules (jets with about a 500 km diameter) visible on the Sun's surface.  Also in the photograph there is noticable color change along the edges of the Sun, this phenomenon is known as limb darkening and is caused by the lower temperatures at the larger heights of the Sun (hence less intense, so darker).  The Sun's magnetic field is moving towards Solar Maximum, the period at which there is the greatest amount of solar activity and sun spots appear, in the next few years.  This means that we can expect a busier, more complex Sun to view in the near future.

APOD 2.2

Historical Supernova Remnant



     RCW 86 is thought to be a remnant of an exploding star that the Chinese discovered in 185 AD.  There was some editing done to this photograph to show the different composition of the supernova.  The blue and green are X-ray energies and the red and yellow are cooler temperatures in infrared.  Because there is a lot of iron present in this supernova but not a neutron star, it suggests that it is a type Ia supernova (thermonuclear explosion that destroys a white dwarf star).  RCW 86 is 8,200 light-years away and has a radius of about 50 light-years.

APOD 2.1

October Skylights (October 28)
                                    
     On October 24th, a coronal mass ejection (gas bubble explosion on the Sun which disrupts solar wind) impacted our magnetosphere, which caused this auroral display.  This picture was taken near Whitby, Ontario, Canada but auroral activity was also noted as far south as Alabama. Aurora consist mostly of electrons that travel along the magnetic field lines.  As they go to the upper atmosphere, they collide with various atoms and molecules, once they collide the atom or molecule stores this energy gained and becomes excited The red color in this picture comes from excited oxygen atoms (above 100 kilometers).  The green color is from oxygen atoms that have returned to the ground state. This phenomenon surely makes for a good photo opportunity.