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

NGC 2371/2


When astronomers first studied this object, they thought they were seeing two, so the two lobes of this planetary nebula were cataloged as NGC 2371 and NGC 2372. Now, the object is often called NGC 2371/2. NGC 2371/2 formed when a Sun-like star reached the end of its life and blew off its outer layers, shedding gas and dust and pushing material out into space to leave a dying, superheated star. That remnant is the bright star between the two lobes at the middle of the image.

Image Credit: NASA / ESA

The Fine Ring Nebula


Fine Ring NebulaThis is the Fine Ring Nebula, an unusual planetary nebula. Planetary nebulae form after some dying stars that have expanded into a red giant phase eject a shell of gas as they evolve into the next phase of their stellar evolution, white dwarfs. Most planetary nebulae are either spherical or elliptical in shape, or bipolar (featuring two symmetric lobes of material), but the Fine Ring Nebula looks like an almost perfectly circular ring. Astronomers believe that this unusually shaped planetary nebula was formed from a binary system. The interaction between the primary star and its orbiting companion shapes the ejected material.

The stellar object at the center of the Fine Ring Nebula does appear to be a binary system, orbiting with a period of 2.9 days. Observations suggest that the binary pair is almost perfectly face-on from our vantage point, implying that the planetary nebula’s structure is aligned in the same way. Our point of view looks down on the torus (doughnut shape) of ejected material, leading to the strikingly circular ring shape in the image.

Image Credit: ESO

Making a White Dwarf


NGC 40 is one of a class of objects called planetary nebulas, so-called because they look like the disk of a planet when viewed with a small telescope. This composite X-ray (blue)/optical (red) image of the nebula NGC 40 shows that it is a bubble of hot gas around a dying Sun-like star. In another 30,000 years or so, the nebula will dissipate, leaving behind a smallt, ultradense white dwarf star about the size of Earth.

Image Credit: X-ray—NASA / CXC  / RIT / J.Kastner & R.Montez.; Optical—NSF / AURA / NOAO / WIYN