Latest Stellar evolution Stories

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...

2010-07-21 06:50:00

Using a combination of instruments on ESO's Very Large Telescope, a UK-led international team of astronomers have discovered the most massive stars to date, one which at birth had more than 300 times the mass of the Sun, twice as much as the currently accepted limit. The existence of these monsters "” millions of times more luminous than the Sun, losing mass through very powerful winds "” may provide an answer to the question "how massive can stars be?" The new results appear in a...

2010-07-19 07:10:00

Astronomers use infrared "eyes" to shed light on black holes. A new infrared image has captured the center of our galaxy in never-before-seen detail--showing stars and gas swirling into the super massive black hole that lurks at the heart of our own Milky Way. "We can't actually see a black hole because, by definition, no light comes out from it," says University of Florida astronomer Steve Eikenberry. "What we can see, though, is the material around the black hole. As the material spirals...

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...

2010-05-19 08:20:00

Astrophysicists at UC Santa Barbara are the first scientists to identify two white dwarf stars in an eclipsing binary system, allowing for the first direct radius measurement of a rare white dwarf composed of pure helium. The results will be published in the Astrophysical Journal Letters. These observations are the first to confirm a theory about a certain type of white dwarf star. The story began with observations by Justin Steinfadt, a UCSB physics graduate student who has been monitoring...

2010-04-20 07:33:08

Scientists at the Naval Research Laboratory have solved a long-standing dilemma about the mass of infrared bright merging galaxies. Because galaxies are the largest directly observable objects in the universe, learning more about their formation is key to understanding how the universe works. Dr. Barry Rothberg and Dr. Jacqueline Fischer, both of the Infrared-Submillimeter Astrophysics & Techniques Section in the Remote Sensing Division, used new data from the 8-meter Gemini-South...

2010-03-22 13:02:55

The Hubble Space Telescope will devote an unprecedented amount of time over the next few years to documenting galaxy evolution in the early universe and to studying whether distant supernovae can be extremely reliable measures of distance across vast regions of the cosmos. In this ambitious new project, Hubble will image more than 250,000 distant galaxies in five directions, providing the first comprehensive view of the structure and assembly of galaxies over the first third of cosmic time....

2010-03-22 07:40:00

About 23% of the Universe is made up of mysterious "Ëœdark matter', invisible material only detected through its gravitational influence on its surroundings. Now two astronomers based at the National Autonomous University of Mexico (UNAM) have found a hint of the way it behaves near black holes. Their results appear in a letter in the journal Monthly Notices of the Royal Astronomical Society. In the early Universe clumps of dark matter are thought to have attracted gas, which then...

2010-03-15 14:05:00

An international team led by Yale University has, for the first time, measured the mass of a type of supernova thought to belong to a unique subclass and confirmed that it surpasses what was believed to be an upper mass limit. Their findings, which appear online and will be published in an upcoming issue of the Astrophysical Journal, could affect the way cosmologists measure the expansion of the universe. Cosmologists use Type Ia supernovae"”the violent explosions of dead cores of stars...

Latest Stellar evolution Reference Libraries

Stellar Astrophysics
2014-01-12 00:00:00

The prominent feature that allows for the existence of life on Earth is the Sun. Radiation from our closest star provides heat and energy to our planet, driving biological processes and providing the necessary conditions for liquid water to naturally exist. But our Sun is only but one star in this vast Universe. And as it turns out, most stars are quite different than the one that illuminates our day. For this reason, scientists have, for hundreds of years, attempted to study the other...

2004-10-19 04:45:43

Hertzsprung-Russell Diagram -- In stellar astronomy, the Hertzsprung-Russell diagram (H-R diagram) shows the relation between the absolute magnitude and the spectral types of stars. It was invented around 1910 by Ejnar Hertzsprung and Henry Norris Russell. There are two equivalent forms. One is the observer's form which plots the color of the star on one axis and the absolute magnitude on the other axis. The theoretician's form plots the temperature of the star on one axis and the...

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

Supernova Remnant -- A supernova remnant (SNR) is made up of the materials left behind by the gigantic explosion of a star in a supernova. There are two possible routes to this end: either a massive star may cease to generate fusion energy in its core, and collapse inward under the force of its own gravity, or a white dwarf star may accumulate material from a companion star until it reaches a critical mass and undergoes a similar collapse. In either case, the resulting supernova...

2004-10-19 04:45:42

Supernova -- A supernova is a star that increases its brightness drastically within a matter of days, making it appear as if a "new" star was born (hence "nova"). The "super" prefix distinguishes it from a mere nova, which also involves a star increasing in brightness, though to a lesser extent and through a much different mechanism. Astronomers have classified supernovae in several classes, according to the lines of different elements that appear in their spectra. The first...

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  • Color; hue; complexion.
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