Satellite News

Artist illustration of a quasar. Image credit: CfAClick to enlarge
Some of the brightest objects in the Universe are quasars. A mystery for decades, most astronomers now believe quasars are the bright centres of galaxies with actively feeding supermassive black holes. A team of researchers have found evidence that there might be something very different at the heart of these galaxies to cause quasars. Instead of black holes consuming matter, there could be objects with powerful magnetic fields that act like propellers, churning matter back into the galaxy.

Artist impression of RS Ophiuchi. Image credit: CfAClick to enlarge
Consider the dramatic binary system of RS Ophiuchi. A tiny white dwarf star, about the size of our Earth, is locked in orbit with a red giant star. A stream of material is flowing from the red giant to the white dwarf. Every 20 years or so, the accumulated material erupts as a nova explosion, brightening the star temporarily. But this is just a precursor to the inevitable cataclysm – when the white dwarf collapses under this stolen mass, and then explodes as a supernova. Dr. Jennifer Sokoloski has been studying RS Ophiuchi since it flared up earlier this year; she discusses what they’ve learned so far, and what’s to come.

Artist illustration of a planetary disk. Image credit: NASA/JPL/SpitzerClick to enlarge
New data from NASA’s Spitzer Space Telescope are giving astronomers a sense of how protoplanetary disks might act as a brake to slow stellar rotation. Young stars spin very quickly, often completing a rotation in less than a day. They could spin even faster, but something is slowing them down. Spitzer gathered data on 500 young stars in the Orion Nebula. The fastest spinning stars don’t have planetary disks around then. It might be that the magnetic field of the star interacts with the planetary disk, slowing the star down.

Ring nebula. Image credit: Goodrich/Bolte/W. M. KeckClick to enlarge
A team of astronomers recently used Arizona’s Infrared-Optical Telescope Array (IOTA) of three linked telescopes to peer 4 billion years into the future, when our Sun balloons up to become a red giant star. The three instruments act as a powerful interferometer, providing a view that would only be possible with a much larger instrument. They observed several red giant stars – the eventual fate of our Sun – and discovered their surfaces to be mottled and varied, covered with enormous sunspots.

Artist illustration of a star and white dwarf. Image credit: CfAClick to enlarge
Earlier this year, astronomers watched a nova explosion blast off the surface of a white dwarf star in the system RS Ophiuchi. Located 5,000 light-years from Earth, RS Ophiuchi consists of a white dwarf and a red giant star locked in orbit – the white dwarf might actually be orbiting within the envelope of the red giant. But this nova was just the taste of what’s to come. The white dwarf is drawing material away from the red giant, and it will eventually gather enough mass to explode as a supernova.

X-Ray image of Proxima Centauri. Credit: ChandraClick to enlarge
If you want to send an interstellar probe, you’re going to chose the closest star. And that would be Proxima Centauri, located only 4.2 light years away. Since they first calculated its distance, astronomers have always assumed that Proxima Centauri was part of the Alpha Centauri triple star system. But recent calculations threw that assumption into doubt. Was its location purely a coincidence? Is Proxima Centauri flying solo through the Milky Way?