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By HubbleSite
Finding lots of dust around stars may not sound like anything astronomers would get excited about. The universe is a dusty place. But dust around a young star can be evidence that planet formation is taking place. This isn’t a new idea. In 1755, German Philosopher Immanuel Kant first proposed that planets formed around our Sun in a debris disk of gas and dust. Astronomers imagined that this process might take place around other stars.
They had to wait until the early 1980s for the first observational evidence for a debris disk around any star to be uncovered. An edge-on debris disk was photographed around the southern star Beta Pictoris. Beta Pictoris remained the poster child for such debris systems until the late 1990s when the Hubble Space Telescope’s second-generation instruments, which had the capability of blocking out the glare of a central star, allowed many more disks to be photographed. Now, they are thought to be common around stars. About 40 such systems have been imaged to date, largely by Hubble.
In this recent image, Hubble uncovers a vast, complex dust structure, about 150 billion miles across, enveloping the young star HR 4796A. A bright, narrow inner ring of dust is already known to encircle the star, based on much earlier Hubble photographs. It may have been corralled by the gravitational pull of an unseen giant planet. This newly discovered huge dust structure around the system may have implications for what this yet-unseen planetary system looks like around the 8-million-year-old star, which is in its formative years of planet construction.
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By HubbleSite
After 45 years of peaceful bliss, the nova T Pyxidis erupted again in 2011. Astronomers took advantage of a flash of light accompanying the blast to map the ejecta from previous outbursts surrounding the double-star system. The team used NASA's Hubble Space Telescope to trace the light as it sequentially illuminated different parts of the disk, a phenomenon called a light echo. Contrary to some predictions, the astronomers were somewhat surprised to find that the ejecta stayed in the vicinity of the star and formed a disk of debris. The discovery suggests that material continues expanding outward along the system's orbital plane, but it does not escape the system.
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By HubbleSite
These Hubble telescope pictures of comet Hale-Bopp show a remarkable "pinwheel" pattern and a blob of free-flying debris near its center. The image at left shows the entire comet; the picture at right is a close-up of the nucleus.
The bright clump of light along the spiral [just above the center of the picture] may be a piece of the comet's icy crust. Although the "blob" is about 3.5 times fainter than the brightest portion at the comet's center, the lump appears brighter because it covers a larger area. The debris follows a spiral pattern outward because the solid center is rotating like a lawn sprinkler, completing a single rotation about once per week.
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