Symbiotic Star System R Aquarii
4.01.1996

Sometimes stars work together to create a spectacular display. Such is the case with the binary star system R Aquarii - a "symbiotic" star system. Here two stars, a variable giant and a white dwarf companion - create both a nebula and a jet.

Shapley 1: An Annular Planetary Nebula
16.08.2011

What happens when a star runs out of nuclear fuel? For stars about the mass of our Sun, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula.

NGC 5189: A Strange Planetary Nebula
11.12.1995

After a Sun-like star can no longer support fusion in its core, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula. This particular planetary nebula has a quite strange and chaotic structure.

The Eye of an Hourglass Nebula
9.02.1996

What's happening in the eye-like center of this planetary nebula? The geometry revealed in this Hubble Space Telescope view of the central part of an "etched hourglass nebula" known as MyCn 18 presents a puzzle. First, the axis of this central region does not line up well with the outer hourglass structure.

Shapley 1: An Annular Planetary Nebula
12.12.1995

This strange structure is what can result when a normal star runs out of nuclear fuel in its core. At that time, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula.

NGC 6369: A Donut Shaped Nebula
18.05.1998

Why isn't the star in the center of the nebula? NGC 6369 appears to be a fairly ordinary planetary nebula. It can be seen with a good telescope in the constellation of Ophiuchus. The gas expelled by the central star is bunched in the shape of a donut or cylinder.

Nebula Nova Cygni Turns On
16.12.1996

Old photographs show no evidence of the above nebula. In 1992, a white dwarf star in Cygnus blew off its outer layers in a classical nova explosion: an event called Nova Cygni 1992. Light flooded the local interstellar neighborhood, illuminated this existing gas cloud, excited the existing hydrogen, and hence caused the red emission.

Methane Dwarf
3.06.1999

While hunting through Sloan Sky Survey data in search of distant quasars, Princeton astronomers Xiaohui Fan and Michael Strauss came upon an undiscovered type of object very nearby - now dubbed a methane dwarf. Marked...

The Sun Erupts
13.08.1995

The sun was captured in 1973 throwing one of the largest eruptive prominences ever recorded. Sol, our sun, is a normal star. It formed about 5 billion years ago, and will last about another 5 billion years. The sun will never explode, and a solar flare will never destroy the earth.

IC 4406: A Seemingly Square Nebula
27.04.1998

How can a round star make a square nebula? This conundrum came to light with the discovery of planetary nebulae like IC 4406. IC 4406 is most probably cylindrical, with its square appearance the result of our vantage point in viewing the cylinder.