Category Archives: Transhuman News

Look up at the night sky ... do you see it? The stars of the cosmos bursting in magnificent explosions of death and rebirth! No? Well, then maybe you are not looking through the "eyes" of the Monitor of All-sky X-ray Image (MAXI) investigation, mounted on the exterior of the International Space Station Kibo module.

MAXI, along with other sky watching instruments, such as Swift, collect data that help researchers discover, study and understand the physics behind the powerful lifecycle of our universe. MAXI was key in two recent publications sharing results that make strides in advancing astrophysics.

Using this collection of instruments, researchers look at snapshots of a celestial dance that took place long ago. These explosive moments and their aftermath happened millions and even billions of years ago, but were only visible recently due to their distance from Earth. The events have something to teach about our past and our future, as we have our own star to be mindful ofthe sun.

MAXI is operated by the Japan Aerospace Exploration Agency (JAXA) and has open access to the space environment. This allows the investigation's sensors to perform an entire sky scan once every orbit of the space station around Earththere are 16 orbits per day. The information from the sky scans downlink to a data center at the Institute of Physical and Chemical Research (RIKEN), a Japanese research institution where the MAXI team disseminates data to scientists around the globe for study.

The first paper focuses on an event MAXI discovered on Nov. 11, 2011, when it captured X-ray data from the ignition of a nova. This explosion occurred in the binary system of a white dwarf and a Be star. The results from the study of this event were published in December in The Astrophysical Journal article titled "Extraordinary Luminous Soft X-Ray Transient MAXI J0158-744 as an Ignition of a Nova on a Very Massive O-Ne White Dwarf." This data shares with the world the sighting of an especially bright X-ray emission, named MAXI J0158-744, which provides evidence of the explosion of the star.

These findings help us understand how the sun will evolve when it becomes a white dwarf 5 billion years from now. They also help researchers learn about the origins of the universe.

"Some novae may be progenitors of type Ia supernovae, which are used as standard candles to measure the distance scalethus expansionof the universe and used in research that was awarded the 2011 Nobel prize in physics," said lead author Mikio Morii, Ph.D., RIKEN. "MAXI J0158-744 offers an extreme case of a nova, and it is therefore very useful for understanding the physics in nova explosions."

A white dwarf is a star that has lost the ability to sustain nuclear fusionmeaning it no longer powers itself. The bigger the white dwarf, the greater the gravitational force and pressure, making it a more-likely candidate to go nova. The white dwarf's gravity allows it to "borrow" mass from nearby sources, such as other stars like the Be star seen in MAXI J0158-744. This mass addition can act like fuel, igniting a thermonuclear explosion and creating an outburst astronomers call a nova.

"The association of a Be star in a nova is very rare. In fact, MAXI J1058-744 is the first of this kind known so far, and there are only a few known binary systems consisting of a white dwarf and a Be star, and no nova has been seen from them," said Morii. "We believe that the large luminosity is related to the fact that the white dwarf is small and heavy, meaning that the surface gravity is strong. Because of the strong gravity, only a small amount of accreted matter from the companion is required to make it sufficiently dense and hot to ignite a thermonuclear runaway. Since the accumulated matter is sufficiently small, the hot fireball was directly visible."

More:
Space station MAXI-mizing our understanding of the universe