APOD 3.3

The Horsehead Nebula is one of the most famous and photographic nebulae in the sky. As you can see it is named the "Horsehead" Nebula because of the shape of a horse's head which is visible in the dark dust cloud at the center of the photo. It is located in the constellation Orion (the Hunter). The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms. Also visible at the bottom left of the picture is a greenish reflection nebulae that reflects the blue light from nearby stars. This APOD is pertinent to the chapter we just finished which was focused on nebulae and the birthing of stars and we also just added Orion to the list of constellations we know.

APOD 3.2

This cosmic bubble is located toward the constellation Canis Major (the Big Dog), surrounds a Wolf-Rayet star. A Wolf-Rayet (WR) stars are evolved, massive stars that lose mass rapidly by means of releasing very strong solar wind. This solar wind that is released is making this cosmic bubble, labeled Sharpless 308, expand. It is already larger than the full moon to a viewer, which corresponds to being 60 light-years in diameter. Emission lines captured from this massive image are dominated by ionized oxygen. This photo pertains to the chapters we are currently studying, chapters 17 and 18, which have to do with stars and identifying their stellar spectra.