Friday, August 26, 2011

A diamond planet? I dunno..

Artistic concept of a pulsar and its tiny companion
Image Credit: Swinburne Astronomy Productions, Swinburne University of Technology
Yesterday, the news wires were alive with excitement.  Astronomers had a confirmed discovery of a planet made out of diamond!  DeBeers better load up a rocket ship and blast off!  But before we put the cart before the horse (and the cart is already halfway across the country while the horse is still munching oats in the barn), let's look a little deeper.  The likely real story is, in my opinion, even more exotic than a planet-sized diamond.

First, let's go over what the astronomers observed.  The team, headed by Professor Matthew Bailes of Swinburne University of Technology in Australia, was looking at a millisecond pulsar.  Pulsar are the remains of very massive stars that exploded as supernovae at the end of the stars' lives.  Pulsars typically contain about 1.3 times the mass of our sun squeezed into a sphere only a dozen miles across.  This is so dense that ordinary atoms cannot exist, and most of the protons and electrons that made up the atoms in the original star merge to form neutrons.  We therefore call these very dense remains of massive stars neutron stars.

Wednesday, August 24, 2011

Y Dwarfs? Because they're cool.

Cool brown dwarf spotted by WISE
Image Credit: NASA/JPL-Caltech/UCLA
That little green dot in the center of the picture above may not look like much, but it is, in fact, one of the first absolutely definitive members of a predicted type of brown dwarf, the "spectral class Y" dwarfs.  It was discovered by astronomers using data from the Wide-field Infrared Survey Explorer, a satellite mission that scanned the entire sky in the infrared wavelengths of light during 2010.  The star above has a temperature of about 25 degrees Celcius, or roughly 80 degrees Fahrenheit -- measurably cooler than the endless summer heat here in Texas.  The discovery was announced yesterday by the WISE team, and an official journal article announcing the discovery has been accepted for publication in the Astrophysical Journal.  Even cooler than the brown dwarf is the fact that this paper was headed up by a good friend of mine, Michael Cushing (now a new faculty member at the University of Toledo).