Fresh Dust Observed on Cassippeia A Star Explosion
Forged in the explosions of massive stars, definitive evidence has been found by astronomers that the universe’s first dust–the celestial stuff that seeded future generations of stars and planets. Using the NASA’s Spitzer Space Telescope, the findings are the most significant clue yet in the long-standing mystery of where the dust in our young universe came from. Exploding stars or super novae were thought to be the primary source but, until now, no one had been able to show that they could create copious amounts of dust. Ten Thousand earth masses worth of dust have been found in the well-known supernova remnant Cassiopeia A by Spitzer’s sensitive infrared detectors.
The January 20, 2007, issue of the Astrophysical Journal carried a report about the discovery and was written by lead author, Jeonghee Rho of NASA’s Spitzer Science Center at the California Institute of Technology in Pasadena. “Now we can say unambiguously that dust–and lots of it–was formed in the ejects of the Cassiopedia A explosion. This finding was possible because Cassiopedia A is in our own galaxy, where it is close enough to study in detail”, said Rho.
Everywhere in the cosmos, space dust can be found as well as in our part of the universe and billions of light-years away in our infant universe. In order for developing stars to collapse and ignite, they must have dust to cool down. Sun-like stars weren’t around long enough to die and leave dust when the universe was young. When the most massive stars in the universe, which are short-lived, die, violent explosions occur. It is thought that the very first exploding massive stars could be responsible for the unaccounted-for dust. Population 111, the first stars are the only stars that formed without any dust.
In addition to supernovae, other objects might contribute to universe’s first dust. Evidence has been found by Spitzer that high energetic holes called quasars and supernova could have dust in their winds. The Cassopeia A supernova remnant located about 11,000 light years away, was analyzed by Rho and her colleagues. Even though this remnant is not from the early universe, its proximity to us helps to address the question of whether supernovae have the ability to synthesize significant amounts of dust. Using Spitzer’s infrared spectrograph, astronomer analyzed the infrared light which spreads light apart to reveal the signatures of different elements and molecules.
“Because Spitzer is extremely sensitive to dust, we were able to make high-resolution maps of dust in the entire structure” said Rho. To find freshly-made dust deeper inside the remnant as well was a surprise to the team. The cooler dust, mixed in with gas is referred to unshocked ejecta and has never been seen before. According to Rho, more studies of other supernovae are needed to put this issue to rest.
This entry was posted on Thursday, January 3rd, 2008 at 3:53 am and is filed under Space Agency News. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
