Latest Stellar evolution Stories
Some of the oldest stars in the Milky Way – a kind of stellar fossils in the outer reaches of our galaxy, contain abnormally large amounts of heavy elements like gold, platinum and uranium. Where these large amounts came from has been a mystery for researchers, since they are usually seen in much later generations of stars. Researchers at the Niels Bohr Institute have been studying these ancient stars for several years with ESO's giant telescopes in Chile in order to trace the origin of...
The very first stars in our universe were not the behemoths scientists had once thought, according to new simulations performed at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Astronomers "grew" stars in their computers, mimicking the conditions of our primordial universe. The simulations took weeks. When the scientists' concoctions were finally done, they were shocked by the results -- the full-grown stars were much smaller than expected. Until now, it was widely believed that...
WASHINGTON, Nov. 10, 2011 /PRNewswire-USNewswire/ -- Using its near-infrared vision to peer 9 billion years back in time, NASA's Hubble Space Telescope has uncovered an extraordinary population of young dwarf galaxies brimming with star formation. While dwarf galaxies are the most common type of galaxy in the universe, the rapid star-birth observed in these newly found examples may force astronomers to reassess their understanding of the ways in which galaxies form. (Logo:...
Astronomers at the universities of Southampton and Oxford have found evidence that neutron stars, which are produced when massive stars explode as supernovae, actually come in two distinct varieties. Their finding also suggests that each variety is produced by a different kind of supernova event. Neutron stars are the last stage in the evolution of many massive stars. They represent the most extreme form of matter: the mass of a single neutron star exceeds that of the entire sun, but...
An international team of astronomers has used the brief but brilliant light of a distant gamma-ray burst as a probe to study the make-up of very distant galaxies. Surprisingly the new observations, made with ESO’s Very Large Telescope, have revealed two galaxies in the young Universe that are richer in the heavier chemical elements than the Sun. The two galaxies may be in the process of merging. Such events in the early Universe will drive the formation of many new stars and may be the...
Astronomers discover how mysterious stars stay so young Mysterious “blue stragglers” are old stars that appear younger than they should be: they burn hot and blue. Several theories have attempted to explain why they don’t show their age, but, until now, scientists have lacked the crucial observations with which to test each hypothesis. Armed with such observational data, two astronomers from Northwestern University and the University of Wisconsin-Madison report that a mechanism...
Astrophysicists have found evidence of black holes destroying stars, a long-sought phenomenon that provides a new window into general relativity. The research, reported in the latest issue of the Astrophysical Journal, also opens up a method to search for the possible existence of a large population of presently undetectable "intermediate mass" black holes which are hypothesized to be precursors to the super-massive black holes at the centers of most large galaxies. The study was carried...
The largest survey to date of distant exploding stars is giving astronomers new clues to what’s behind the Type Ia supernovae they use to measure distances across the cosmos. These stellar explosions helped astronomers conclude more than a decade ago that dark energy is accelerating the expansion of the universe, and today (Tuesday, Oct. 4) earned the discoverers – including UC Berkeley physicist Saul Perlmutter – the 2011 Nobel Prize in Physics. But what caused them was a mystery....
[ Watch the Video ] University of Manchester astronomers used the European Southern Observatory's Very Large Telescope (VLT) to discover the Fried Egg Nebula. The newly discovered star has a diameter of about a thousand times bigger than the Sun and is about 13,000 light-years away from Earth. It is the closest hypergiant found so far and shines about 500,000 times brighter than the Sun "This object was known to glow brightly in the infrared but, surprisingly, nobody had...
About 5 thousand million years from now, our Sun will expand into a red giant, swelling to such a size that it may swallow the Earth. It will then begin to shed huge amounts of dust, surrounding itself with an expanding circumstellar envelope (CSE) that ultimately will become a planetary nebula. New insights into this process have been revealed by ESA's Herschel Space Observatory, which is providing unprecedented images of the complex, outer structure of a nearby CSE. As part of a...
Latest Stellar evolution Reference Libraries
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...
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...
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...
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...
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...
