Latest White dwarf Stories

2007-03-07 13:09:38

Proof that certain double star systems can erupt in full-blown explosions and then continue to flare up with smaller bursts has been spotted by the ultraviolet eyes of NASA's Galaxy Evolution Explorer. The finding bolsters a 20-year-old theory that suggests such double-star, or binary systems, should eventually undergo both types of explosion, rather than just one or the other. It implies the systems probably cycle between two blast types, hiccupping every few weeks with small surges until...

2007-02-12 08:55:00

A bunch of rowdy comets are colliding and kicking up dust around a dead star, according to new observations from NASA's Spitzer Space Telescope. The dead star lies at the center of the much-photographed Helix nebula, a shimmering cloud of gas with an eerie resemblance to a giant eye. "We were surprised to see so much dust around this star," said Dr. Kate Su of the University of Arizona, Tucson, lead author of a paper on the results appearing in the March 1 issue of Astrophysical Journal...

2007-02-07 12:53:43

The universe contains one and a half times more calcium than previously assumed. This conclusion was drawn by astronomers of the SRON Netherlands Institute for Space Research, after observations with ESA's XMM-Newton X-ray observatory. This research offers scientists new insights in the formation history of the elemental building blocks of the cosmos in which supernovae play a crucial role. The iron in our blood, the oxygen we breathe, the calcium in our bones, the silicon in the sand box,...

2007-01-09 16:15:00

Using NASA's Chandra X-ray Observatory, scientists have created a stunning new image of one of the youngest supernova remnants in the galaxy. This new view of the debris of an exploded star helps astronomers solve a long-standing mystery, with implications for understanding how a star's life can end catastrophically and for gauging the expansion of the universe. Over 400 years ago, sky watchers -- including the famous astronomer Johannes Kepler -- noticed a bright new object in the night...

2007-01-04 14:55:00

Evidence for a significant new class of supernova has been found with NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton. These results strengthen the case for a population of stars that evolve rapidly and are destroyed by thermonuclear explosions. Such "prompt" supernovas could be valuable tools for probing the early history of the cosmos. A team of astronomers uncovered a puzzling situation when they examined X-ray data from DEM L238 and DEM L249, the remnants of...

2006-12-01 17:25:00

Using observations of 17 supernovae made over more than 10 years with ESO's Very Large Telescope and the McDonald Observatory's Otto Struve Telescope, astronomers inferred the shape and structure of the debris cloud thrown out from Type Ia supernovae. Such supernovae are thought to be the result of the explosion of a small and dense star - a white dwarf - inside a binary system. As its companion continuously spills matter onto the white dwarf, the white dwarf reaches a critical mass, leading...

2006-10-19 09:00:22

First Directly Imaged Brown Dwarf Companion to an Exoplanet Host Star Astronomers have detected a new faint companion to the star HD 3651, already known to host a planet. This companion, a brown dwarf, is the faintest known companion of an exoplanet host star imaged directly and one of the faintest T dwarfs detected in the Solar neighbourhood so far. The detection yields important information on the conditions under which planets form. "Such a system is an interesting example that might...

2006-10-06 05:25:00

Scientists using NASA's Swift satellite have observed two dozen recent star explosions, called supernovae, quickly after the event and have discovered never-before-seen properties, some of which run counter to prevailing theories. In one observation, they have confirmed the origin of Type Ia supernovae, an important class of explosions used to measure distances and dark energy. In other observations they have found new mechanisms to produce X-rays and ultraviolet light. The findings have...

2006-09-12 12:00:00

"For the first time, we have clearly established a 'genetic difference' between stars in the disc and the bulge of our Galaxy," said Manuela Zoccali, lead author of the paper presenting the results in the journal Astronomy and Astrophysics [1]. "We infer from this that the bulge must have formed more rapidly than the disc, probably in less than a billion years and when the Universe was still very young." The Milky Way is a spiral galaxy, having pinwheel-shaped arms of gas, dust, and stars...

2006-09-12 09:05:00

Galactic Bulge and Disc Stars Shown To Have Different Oxygen Abundances Looking in detail at the composition of stars with ESO's VLT, astronomers are providing a fresh look at the history of our home galaxy, the Milky Way. They reveal that the central part of our Galaxy formed not only very quickly but also independently of the rest. "For the first time, we have clearly established a 'genetic difference' between stars in the disc and the bulge of our Galaxy," said Manuela Zoccali, lead...

Latest White dwarf Reference Libraries

2004-10-19 04:45:43

White Dwarf -- A white dwarf is a a star supported by electron degeneracy. A star like our Sun will become a white dwarf when it has exhausted its nuclear fuel. Near the end of its nuclear burning stage, such a star goes through a red giant phase and then expels most of its outer material (creating a planetary nebula) until only the hot (T > 100,000 K) core remains, which then settles down to become a young white dwarf. A typical white dwarf is half as massive as the Sun, yet only...

2004-10-19 04:45:42

Stellar Evolution -- Stellar evolution is the process of formation, life, and death of stars. It is one of the major topics of cosmogony. Star Birth and Life A star starts out as an enormous cloud of gas and dust many light-years across. Star formation begins when the cloud begins to condense under its own gravity. The processes that initiate this contraction are not fully understood. The cloud fragments fuse into stellar mass clouds known as protostars. Protostars do not emit...

2004-10-19 04:45:42

Nova -- A nova is an enormous nuclear explosion caused by the accretion of hydrogen onto the surface of a white dwarf star. When a white dwarf has a close companion star, the companion will often begin to have its outer atmosphere drawn away from it by the white dwarf's gravity as the companion star ages and expands into a red giant. The gases so captured consist primarily of hydrogen and helium, the two principle constituents of matter in the universe. The gases are compacted on the...

2004-10-19 04:45:41

Cataclysmic Variable Star -- Cataclysmic variables are a class of binary stars containing a white dwarf and a companion star. The companion star is usually a red dwarf, although in some cases it is another white dwarf or a slightly evolved star (subgiant). Several hundreds of cataclysmic variables are known. From the observational viewpoint, cataclysmic variables are relatively easy to discover. They are usually quite blue objects, as the majority of stars are red. The variability of...

More Articles (4 articles) »
Word of the Day
  • One of a religious order living in a convent or in community; a monk: opposed to anchoret or hermit (one who lives in solitude).
  • A social bee.
This word comes from the Latin 'coenobium,' convent, which comes from the Greek 'koinobios,' living in community.