Latest Stellar evolution Stories

2010-12-22 06:20:00

New observations by University of Michigan astronomers add weight to the theory that the most massive stars in the universe could form essentially anywhere, including in near isolation; they don't need a large stellar cluster nursery. This is the most detailed observational study to date of massive stars that appear (from the ground) to be alone. The scientists used the Hubble Space Telescope to zoom in on eight of these giants, which range from 20 to 150 times as massive as the Sun. The...

2010-12-11 13:50:00

A circular rainbow appears like a halo around an exploded star in this new view of the IC 443 nebula from NASA's Wide-field Infrared Survey Explorer, or WISE. When massive stars die, they explode in tremendous blasts, called supernovae, which send out shock waves. The shock waves sweep up and heat surrounding gas and dust, creating supernova remnants like the one pictured here. The supernova in IC 443 happened somewhere between 5,000 and 10,000 years ago. In this WISE image, infrared light...

2010-12-08 07:05:00

A team of astronomers led by graduate student Naslim and her supervisor Dr Simon Jeffery from Armagh Observatory in Northern Ireland has found what at first sight appears to be the most zirconium-rich star ever discovered. Zirconium, the material used by jewelers to make false diamonds, glitters in clouds above the star's surface. The scientists publish their results in the journal Monthly Notices of the Royal Astronomical Society. The team made the discovery while looking for chemical clues...

2010-12-03 08:10:00

A team of physicists from the University of Toronto and Rutgers University have mimicked the explosion of a supernova in miniature. A supernova is an exploding star. In a certain type of supernova, the detonation starts with a flame ball buried deep inside a white dwarf. The flame ball is much lighter than its surroundings, so it rises rapidly making a plume topped with an accelerating smoke ring. "We created a smaller version of this process by triggering a special chemical reaction in a...

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 11:14:41

Astronomers find cosmic dust annoying when it blocks their view of the heavens, but without it the universe would be devoid of stars. Cosmic dust is the indispensable ingredient for making stars and for understanding how primordial diffuse gas clouds assemble themselves into full"“blown galaxies. "Formation of galaxies is one of the biggest remaining questions in astrophysics," said Andrey Kravtsov, associate professor in astronomy & astrophysics at the University of Chicago....

2010-11-21 15:10:29

Observing the X-ray-bright gas in the halo of the Milky Way, ESA's XMM-Newton has gathered new data which favor a process involving fountains of hot gas in our Galaxy. Such a scenario, with the gas flowing from the galactic disc into the halo where it then condenses into cooler clouds and subsequently falls back to the disc, confirms the importance of supernova explosions in forging the evolution of the interstellar medium and of the entire Galaxy. The interstellar medium (ISM) in the Milky...

2010-11-18 09:53:02

Elliptical galaxies were once thought to be aging star cities whose star-making heyday was billions of years ago. But new observations with NASA's Hubble Space Telescope are helping to show that elliptical galaxies still have some youthful vigor left, thanks to encounters with smaller galaxies. Images of the core of NGC 4150, taken in near-ultraviolet light with the sharp-eyed Wide Field Camera 3 (WFC3), reveal streamers of dust and gas and clumps of young, blue stars that are significantly...

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...

2010-10-15 11:11:41

OSU's Kazantzidis studies the behavior of galaxies, black holes through modeling & simulation at the Ohio Supercomputer Center An Ohio State University astronomer is working to unlock some of the mysteries surrounding the formation of vast galaxies and the evolution of massive black holes with his own large constellation of silicon wafers. Over the last year, two research teams led by Stelios Kazantzidis, a Long-Term Fellow at the Center for Cosmology and Astro-Particle Physics (CCAPP) at...

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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