Wednesday, November 4, 2009

Carbon atmosphere neutron star

Cas A: a neutron star with atmosphere


The hot neutron stars left behind by supernova explosions are thought to posses a thin atmosphere, but despite extensive searches, observations have so far been unable to confirm the atmospheric composition of an isolated neutron star. Wynn Ho and Craig Heinke have now repaired that omission by analysing archival observations — made by the Chandra satellite observatory in 2004 — of the compact X-ray source in the centre of the Cassiopeia A supernova remnant. The spectrum of the Cas A neutron star corresponds to that predicted for a carbon atmosphere, and suggests that there is nuclear burning in the surface layers of what may be, at about 300 years old, the youngest known neutron star.

LetterA neutron star with a carbon atmosphere in the Cassiopeia A supernova remnant

Wynn C. G. Ho & Craig O. Heinke

Friday, October 30, 2009

Is Fermi seeing Dark Matter?

The Fermi Haze: A Gamma-Ray Counterpart to the Microwave Haze..
A team of Harvard researchers has upped the ante in the race to discover the true nature of dark matter. see this from Sky and Telescope.

Thursday, October 22, 2009

Making Xray emission from binary stars and blackholes in the lab.

From Nature: A team of researchers has used a high-power laser, a tiny hollow plastic pellet and silicon foil to reproduce the X-rays emitted by stars. Shinsuke Fujioka of Osaka University in Japan and his colleagues fired 12 green laser beams at the pellet, compressing and heating it. As the plastic became superheated, silicon atoms near the pellet were ionized, releasing X-rays resembling those seen in two distant binary star systems, where one star is orbiting another.

The authors believe the study could help to refine models for such astronomical systems, and that the radiation from the superheated pellets might recreate the conditions thought to exist at the edge of a black hole.

Check out Stars in a Pellet journal paper.

Tuesday, September 22, 2009

Discovery of a rotating radio transient by a high school student

News that appeared in universe today:

A high-school student from West Virginia has discovered a new astronomical object, a strange type of neutron star called a rotating radio transient. Lucas Bolyard, a sophomore at South Harrison High School in Clarksburg, WV, made the discovery while participating in a project in which students are trained to search through data from the Robert C. Byrd Green Bank Telescope (GBT). Bolyard made the discovery in March, after he already had studied more than 2,000 data plots from the GBT and found nothing. Read the rest here.

Monday, September 14, 2009

Magnetic fields play larger role in star formation than previously thought

Press release from Astronomy.com:

The simple picture of star formation calls for giant clouds of gas and dust to collapse inward due to gravity, growing denser and hotter until igniting nuclear fusion. In reality, forces other than gravity also influence the birth of stars. New research shows that cosmic magnetic fields play a more important role in star formation than previously thought.

A molecular cloud is a cloud of gas that acts as a stellar nursery. When a molecular cloud collapses, only a small fraction of the cloud's material forms stars. Scientists aren't sure why.

Gravity favors star formation by drawing material together, therefore some additional force must hinder the process. Magnetic fields and turbulence are the two leading candidates. A magnetic field is produced by moving electrical charges. Stars and most planets, including Earth, exhibit magnetic fields. Magnetic fields channel flowing gas, making it hard to draw the gas from all directions, while turbulence stirs the gas and induces an outward pressure that counteracts gravity.

Read the rest of the news here.

Wednesday, March 25, 2009

Evolution and the Canadian Science Minister

I found this Nature Article fascinating about the Canadian science minister. It is an important position - and terrifying that someone who might not understand the basics of science is in it.