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Archive for April 9, 2013

Retired Star Found With Planets And Debris Disc

April 9, 2013 1 comment

Copyright ESA/Bonsor et al (2013)

Copyright ESA/Bonsor et al (2013)

ESA’s Herschel space observatory has provided the first images of a dust belt – produced by colliding comets or asteroids – orbiting a subgiant star known to host a planetary system.

After billions of years steadily burning hydrogen in their cores, stars like our Sun exhaust this central fuel reserve and start burning it in shells around the core. They swell to become subgiant stars, before later becoming red giants.

At least during the subgiant phase, planets, asteroids and comet belts around these ‘retired’ stars are expected to survive, but observations are needed to measure their properties. One approach is to search for discs of dust around the stars, generated by collisions between populations of asteroids or comets.

Thanks to the sensitive far-infrared detection capabilities of the Herschel space observatory, astronomers have been able to resolve bright emission around Kappa Coronae Borealis (κ CrB, or Kappa Cor Bor), indicating the presence of a dusty debris disc.

Full Story: http://www.esa.int/Our_Activities/Space_Science/Herschel/Retired_star_found_with_planets_and_debris_disc

Carbon’s Role In Atmosphere Formation


A new study of how carbon is trapped and released by iron-rich volcanic magma offers clues about the early atmospheric evolution on Mars and other terrestrial bodies.

The composition of a planet’s atmosphere has roots deep beneath its surface. When mantle material melts to form magma, it traps subsurface carbon. As magma moves upward toward the surface and pressure decreases, that carbon is released as a gas. On Earth, carbon is trapped in magma as carbonate and degassed as carbon dioxide, a greenhouse gas that helps Earth’s atmosphere trap heat from the sun. But how carbon is transferred from underground to the atmosphere in other planets — and how that might influence greenhouse conditions — wasn’t well understood.

“We know carbon goes from the solid mantle to the liquid magma, from liquid to gas and then out,” said Alberto Saal, professor of geological sciences at Brown and one of the study’s authors. “We want to understand how the different carbon species that are formed in the conditions that are relevant to the planet affect the transfer.”

Full Story: http://news.brown.edu/pressreleases/2013/04/magma