Latest White dwarf Stories

2010-12-02 20:39:28

Type Ia supernovae (SNe Ia) play an important role as cosmological distance indicators and have been used successfully to determine cosmological parameters, which resulted in the discovery of the accelerating expansion of the Universe. However, the exact nature of SN Ia progenitors is still not well understood. There is a popular theory that SNe Ia originate from runaway thermonuclear events in carbon"“oxygen white dwarves (CO WD) in binary systems. The CO WD accretes material from its...

2010-11-23 08:00:00

An international team of astronomers have discovered a unique and exotic star system with a very cool methane-rich (or T-) dwarf star and a "Ëœdying' white dwarf stellar remnant in orbit around each other. The system is a "ËœRosetta Stone' for T-dwarf stars, giving scientists the first good handle on their mass and age. The team, led by Dr Avril Day-Jones of the Universidad de Chile and including Dr David Pinfield of the University of Hertfordshire as well as astronomers...

2010-11-16 10:31:47

Sometimes when you're looking for one thing, you find something completely different and unexpected. In the scientific endeavor, such serendipity can lead to new discoveries. Today, researchers who found the first hypervelocity stars escaping the Milky Way announced that their search also turned up a dozen double-star systems. Half of those are merging and might explode as supernovae in the astronomically near future. All of the newfound binary stars consist of two white dwarfs. A white dwarf...

2010-10-28 10:20:24

Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics. "This neutron star is twice as massive as our Sun. This is surprising, and that much mass means that several theoretical models for the internal composition of neutron stars now are ruled out," said Paul Demorest, of the National Radio Astronomy Observatory...

2010-08-13 08:00:00

Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation. A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion. "In human terms, this was an...

2010-07-13 06:40:00

When a star explodes as a supernova, it shines so brightly that it can be seen from millions of light-years away. One particular supernova variety - Type Ia - brightens and dims so predictably that astronomers use them to measure the universe's expansion. The resulting discovery of dark energy and the accelerating universe rewrote our understanding of the cosmos. Yet the origin of these supernovae, which have proved so useful, remains unknown. "The question of what causes a Type Ia supernova...

2010-05-27 09:05:00

Stellar explosions provide the key to understanding the fate of the universe The mysteries of the Universe and how we came to be are set to be unlocked by a technique for modeling fluids, similar to one which is becoming increasingly popular within the film industry to improve the realism of special effects. Theoretical Astrophysics student, Fergus Wilson from the University of Leicester, is currently utilizing a fluid modeling technique within his doctoral research to enable investigation of...

2010-05-24 07:25:58

A team of astronomers led by Dr Gavin Ramsay of Armagh Observatory have spotted violent eruptions from an interacting pair of stars that orbit around each other every 25 minutes. Unusually, these outbursts take place at regular and predictable intervals, erupting every two months. The new observations were made using the fully robotic Liverpool Telescope sited in the Canary Islands and the orbiting Swift observatory. The results will appear in the journal Monthly Notices of the Royal...

2010-05-22 07:45:08

The finding sheds light on some universal mysteries, including the possibility that exploding stars created some of the matter that makes up our bodies. Not all explosions are created equal "“ it's as true for film effects as it is for stars. An international team of scientists, including a University of Arizona astronomer, has identified a third type of exploding star, or supernova. Until now, scientists had only observed two kinds of supernovae "“ either hot, young giants that...

2010-05-19 13:32:35

In the past decade, robotic telescopes have turned astronomers' attention to scads of strange exploding stars, one-offs that may or may not point to new and unusual physics. But supernova (SN) 2005E, discovered five years ago by the University of California, Berkeley's Katzman Automatic Imaging Telescope (KAIT), is one of eight known "calcium-rich supernovae" that seem to stand out as horses of a different color. "With the sheer numbers of supernovae we're detecting, we're discovering weird...

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...

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Word of the Day
  • A fool; a simpleton: a term of abuse common in Ireland and to a less extent in the Gaelic-speaking parts of Scotland.
This word is partly Irish in origin.