Latest White dwarf Stories

2007-07-13 08:40:00

VLT Provides Evidence for Type Ia Supernovae Scenario A unique set of observations, obtained with ESO's VLT, has allowed astronomers to find direct evidence for the material that surrounded a star before it exploded as a Type Ia supernova. This strongly supports the scenario in which the explosion occurred in a system where a white dwarf is fed by a red giant. Because Type Ia supernovae are extremely luminous and quite similar to one another, these exploding events have been used extensively...

2007-05-22 12:35:00

Andromeda, the nearest major galaxy to the Milky Way, is shown here in this wide-field optical image from Kitt Peak. The central region of Andromeda is shown in a composite image, with X-rays from NASA's Chandra X-ray Observatory (blue) combined with the optical image. Astronomers believe that Andromeda, also known as Andromeda Galaxy (M31), and the Milky Way will merge in a few billion years. In the composite image, hot, X-ray bright gas is seen to envelop the central region of Andromeda....

2007-05-09 09:06:08

ESA's X-ray observatory XMM-Newton has revealed a new class of exploding stars "“ where the X-ray emission "Ëœlives fast and dies young'. The identification of this particular class of explosions gives astronomers a valuable new constraint to help them model and understand stellar explosions. Exploding stars called novae remain a puzzle to astronomers. "Modelling these outbursts is very difficult," says Wolfgang Pietsch of the Max Planck Institut fr Extraterrestrische Physik....

2007-04-17 17:35:00

An Anglo-American team of astronomers have used the Advanced Camera for Surveys on the Hubble Space Telescope (HST) to obtain the first direct optical images of the aftermath of a recent titanic explosion that took place in a star system 5,000 light years from Earth. In a talk on Tuesday 17 April at the Royal Astronomical Society National Astronomy Meeting in Preston, Professor Michael Bode of Liverpool John Moores University will describe how these unique observations shed new light on the...

2007-04-17 10:45:00

Cambridge, MA - Astronomers have found the lowest mass white dwarf known in our galaxy: a Saturn-sized ball of helium containing only about one-fifth the mass of the Sun. In addition, they have spotted the source of the white dwarf's radical weight-loss plan. An unseen companion, likely another white dwarf, has sucked away much of the tiny white dwarf's material, leaving it a shadow of its former self. "This star is bizarre," said Warren Brown of the Harvard-Smithsonian Center for...

2007-04-04 13:20:00

It has been a mystery for astronomers how certain dying stars have their colossal quantities of material blown out into the universe and shrink into objects called "white dwarves". This is the basis of a ground-breaking new theory by astrophysicists Anja C. Andersen from the Dark Cosmology Centre at the University of Copenhagen and Susanne Höfner of the University of Uppsala. Earth and the other planets in our solar system are built up of elements which have been produced in earlier...

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...

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
  • The call or cry of a bird or other animal to its mate or its young.
'Call-note' is newer than 'bird-call,' which originally referred to 'an instrument for imitating the note of birds' but now also refers to 'the song or cry of a bird.'