Mergers and Acquisitions

While most galaxies live their own separate, solitary lives, others stray a little too close to a near neighbor. These two galaxies, cataloged as NGC 6285 (left) and NGC 6286 (right)—and as Arp 293 (the pair), have done just that. They are interacting with their mutual gravitational attraction pulling wisps of gas and streams of dust from each other, distorting their shapes.

Image Credit: NASA / ESA

NGC 6153

A nitrogen-rich nebula This is NGC 6153. The faint blue haze is what remains of a star like the sun after it had depleted most of its fuel. When that happened, the outer layers of the star were ejected and then ionized by the ultraviolet light from hot core of the star, forming the nebula.

NGC 6153 is a planetary nebula which contains large amounts of neon, argon, oxygen, carbon and chlorine—up to three times more than can be found in our solar system. It contains five times more nitrogen than our sun! It could be that the star developed higher levels of these elements as it grew and evolved, but it is more likely that the star originally formed from a cloud of material that already contained an abundance of those elements.

Image Credit: ESA / NASA

The Oyster Nebula

A hazy nebulaThis is a false color image from Hubble’s Wide Field Planetary Camera 2 of NGC 1501, a complex planetary nebula located in the constellation of Camelopardalis (The Giraffe). NGC 1501 is a planetary nebula that is just under 5,000 light-years away from us. It has a central star shining brightly from within the nebula’s cloud. This bright pearl embedded in its glowing shell gives rise to the nebula’s popular nickname—the Oyster Nebula.

While NGC 1501’s central star blasted off its outer shell long ago, it still remains very hot and luminous, but it can be difficult to spot through modest telescopes. The star seems to be pulsating, varying quite significantly in brightness over a timescale of just half an hour. While variable stars are not unusual, it is unusual to find one at the heart of a planetary nebula.

Image Credit: ESA / NASA