The Little Ghost Nebula


NGC 6369 is a planetary nebula also known as the Little Ghost Nebula. Planetary nebulae aren’t related to planets. They’re gaseous shrouds created at the end of a Sun-like star’s life as the dying star’s outer layers expand while its core shrinks to become a white dwarf. The white dwarf radiates strongly at ultraviolet wavelengths, powering the expanding nebula’s glow. NGC 636’s main round structure is about a light-year across, and the glow from its ionized oxygen, hydrogen, and nitrogen atoms are colored blue, green, and red respectively. The Little Ghost Nebula offers a glimpse of the likely fate of our Sun which could produce its own planetary nebula about 5 billion years from now.

Image Credit: NASA

IC 1295


The glowing green planetary nebula IC 1295 surrounds a dim and dying star. It is located about 3300 light-years away in the constellation of Scutum (The Shield). The white dwarf star is softly shedding its outer layers, like an unfolding flower in space. It will continue this process for a few tens of thousands of years.

Image Credit: ESO

NGC 2440


Hubble reveals NGC 2440This Hubble Space Telescope image shows the colorful end of a star like the Sun. This star is casting off its outer layers of gas, which formed a cocoon around the star’s remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, a white dwarf, is the white dot in the center. Our Sun will eventually burn out and surround itself with stellar debris, but that’s not expected for another 5 billion years or so.

The galaxy is filled with these stellar relics called planetary nebulae. (They have nothing to do with planets. 18th- and 19th-century astronomers used that name because through small telescopes the nebulae resembled the disks of the planets Uranus and Neptune.) This planetary nebula in this image is named NGC 2440. The white dwarf at the center of NGC 2440 is one of the hottest known, with a surface temperature of more than 200,000°C. The nebula’s chaotic structure suggests that the star shed its mass in multiple stages. During each outburst, the star blew off material in a different direction, resulting in the two bowtie-shaped lobes.

The material expelled by the star glows with different colors depending on its composition, its density and how close it is to the hot central star. Blue samples helium; blue-green oxygen, and red nitrogen and hydrogen.

Image Credit: NASA / ESA

A Bipolar Nebula


The icy blue wings of Hen 2-437Hen 2-437 is a planetary nebula, one of about 3,000 such objects found so far in the Milky Way. Planetary nebulae form when an aging low-mass star—such as the Sun—reaches the final stages of life. The star expands to become a red giant and then throws off its outer layers into space. After that outburst, the star slowly shrinks to form a white dwarf, and the expelled gas is slowly compressed and pushed outwards by stellar winds. Hen 2-437 is a bipolar nebula,  the material ejected by the dying star has streamed out into space to create two blue lobes.

Image Credit: ESA / NASA