In a brief review regarding the nature of supernovae, Italian astronomer Nino Panagia highlights the major issues associated with the current understanding of supernovae. Panagia points out that while supernovae of Type Ia are used as perfect “standard candles” (that is, distance markers), they are not so perfect. Type Ia supernovae provide the evidence for the accelerated expansion of our universe and if their results are questioned, so must the conclusions about our universe. Read about the questions that remain regarding supernovae explosions and their nature, online here.
You hear a lot about supernovae explosions, but did you ever think what it’s like to be there when a Type II (core-collapse) supernova explodes? In a paper released today, Canadian astronomers provide the latest computer simulations of Type II supernovae. You can see their animations, which have been enhanced with the effects of the additional heating caused by neutrinos, online at http://www.cita.utoronto.ca/~fernandez/alpha_movies.html And if you wish to read about how these simulations were done, you can read their paper online at http://xxx.lanl.gov/PS_cache/arxiv/pdf/0812/0812.4574v1.pdf
If you think cosmologists are settled about the best model of the universe, you are mistaken. Just today, there appeared a paper online at http://xxx.lanl.gov/PS_cache/arxiv/pdf/081/0812.3912v1.pdf which seeks to provide an alternative to the standard dark energy model while still explaining the supernovae Type Ia results which lead us to believe in the accelerating expansion of the universe. In another paper available online at http://xxx.lanl.gov/PS_cache/arxiv/pdf/0809/0809.3761v2.pdf and accepted for publication in Physical Review Letters, Canadian astronomers provide yet another alternative view of cosmology, without the need for the standard view of dark energy. And yet another paper on dark energy modeling was released today, and is available online at http://xxx.lanl.gov/PS_cache/arxiv/pdf/081/0812.3901v1.pdf within which the interactions of dark energy and cold dark matter are examined.
Cosmic dust is an important field of study as it is the dust in nebulae which helps form things such as stars and planets. So where did all the dust out there come from? One NASA scientist joined a group of Japanese astronomers in modeling the formation and evolution of dust in primordial supernovae. They use observations of supernova remnants from the oldest known supernovae (called Population III supernovae) to test the results of their models. Learn more about the origins of cosmic dust online at http://xxx.lanl.gov/PS_cache/arxiv/pdf/0812/0812.1448v1.pdf And if you are curious about cosmic dust in general, you may want to take a look at a popular level presentation done by a colleague (Joe Weingartner) at http://physics.gmu.edu/~joe/NOVAC.pdf
The accelerating expansion of the universe and the existence of dark energy was necessary to explain the first results of a survey of Type Ia supernovae. In a continuing report about high redshift (most distant) supernovae, scientists of the ESSENCE team provide the latest information from their data after four years of operation. If you were curious about the acronym, ESSENCE stands for “Equation of State: SupErNovae trace Cosmic Expansion.” To learn more about this effort to better understand dark energy and the accelerating expansion of the universe, see the team’s latest paper at http://xxx.lanl.gov/PS_cache/arxiv/pdf/0811/0811.4424v1.pdf