In a paper to be published in the Monthly Notices of the Royal Astronomical Society, available online now here, astronomers report on their use of x-ray spectroscopy with the European Space Agency’s (ESA) XMM-Newton spacecraft the bulge of the Andromeda Galaxy also known as M31. The astronomers conclude that “the results indicate that iron ejecta of type Ia supernovae are partly-mixed with the hot gas.” Type Ia supernovae are those supernovae produced within a binary star system, whose white dwarf component has gone supernova.
If you haven’t noticed, most computer models, or simulations of supernovae explosions are merely two-dimensional. This is largely because of the computing speed and processing required to perform a full three dimensional computer model is often prohibitive. In a paper submitted to the Astrophysical Journal, available online now here, German astrophysicists announced today the first successful 3D modeling of a 15.5 solar mass blue supergiant supernova explosion. If you think there’s a lot of violence reported in today’s news stories, consider “iron-dominated fingers overtaking oxygen-rich bullets.” But don’t forget, that without such cosmic fireworks, we could not exist, as these explosions produce much of the heavier chemical elements which make up you and me.
Type Ia supernovae are those supernovae which develop within a binary star system, where one of the stars has already ended its life as a white dwarf, and manages to “steal” so much material from its companion star that it ends up collapsing under its own weight, and the rebound gives us a supernova explosion. These type of supernovae are especially of interest to astronomers because it was discovered that they can be used as a way to gauge the distance to remote galaxies which have this type of supernova explosion. In fact, it’s these type of supernovae which provided the initial evidence for astronomers that the universe is not only expanding, but it is accelerating in its expansion. Analysis of the spectra of Type Ia supernovae is also of interest, and now in a paper released this week, available online here, astronomers have discovered that the use of a mathematical tool called wavelets, can provide superior analysis of Type Ia supernovae spectra.
In a paper submitted to Nature, available online now here, an international group of astronomers claim that they have discovered a new type of supernova explosion. Astronomers categorize supernovae as either Type I or Type II. Within the Type I category, supernovae can be categorized as either Type Ia, Ib or Ic. Some astronomers now subdivide Type II supernovae as well, into Type IIL or IIP. Type Ia are probably best known for their use as a so-called standard candle, as they represent the explosion of a white dwarf in a binary star system which has accumulated so much material from the companion star, that its mas goes beyond what is called the Chandrasekhar mass limit, leading to the supernova explosion. On 13 January 2005, astronomers detected a supernova explosion in the vicinity of NGC 1032, a galaxy over 100 million light years distant in the constellation Cetus. The supernova was designated SN 2005E. While spectra may have indicated that this was a Type Ib supernova, further investigations led astronomers to believe that the mass of the progenitor star was far from what would be expected for a Type Ib supernova. Thus, the conclusion that these astronomers have discovered a new type of supernova.
In 2005 there was a supernova noticed that took place in a galaxy simply known as NGC 266. The supernova was named supernova (SN) 2005gl. Supernovae are named based upon the year of discovery and the letters that follow give you an idea of how many other supernovae were discovered in that year before it. Remember SN 1987A, it was the first supernova discovered in 1987. Anyhow, as with SN 1987A, astronomers have spent these years trying to determine if they could identify the star that went supernova (called the progenitor) in NGC 266. Although it was believed that the star had been identified before, this paper confirms the progenitor was a star known as NGC266_LBV 1. What is special about this is that, as with SN 1987A, SN 2005gl apparently developed from a blue supergiant star, which is not the type you would expect to explode as a supernova, according to the current models of the life cycle of stars. Read more about SN 2005gl online now here (subscription required) or pick up a copy of the latest issue of the journal Nature.
In 2005, astronomers observed a supernova explosion within the Whirlpool Galaxy also known as M51. Actually the explosion occurred in M51 about 25 million years ago, but because of its distance from us, we on Earth didn’t notice it until 2005. Nonetheless, after a year long focus study on SN 2005cs, including “numerous unfiltered observations obtained by amateur astronomers,” scientists have been able to estimate that this Type II supernova ejected material equivalent to about 10 times the mass of our own Sun, with an explosive energy “equivalent to a billion megatons of TNT going off every second for a trillion years.” Learn more about SN 2005cs by reading the advanced copy of an article to appear in the Monthly Notices of the Royal Academy of Sciences online now at http://xxx.lanl.gov/PS_cache/arxiv/pdf/0901/0901.2075v1.pdf