Astronomy Now Home
Home Magazine Resources Store

On Sale Now!



The October 2014 issue of Astronomy Now is on sale! Order direct from our store (free 1st class post & to UK addresses). Astronomy Now is the only astronomy magazine specially designed to be read on tablets and phones. Download the app from Google Play Store or the Apple App Store.



Top Stories



Earthshine used to test life detection method
...By imagining the Earth as an exoplanet, scientists observing our planet's reflected light on the Moon with ESO's Very Large Telescope have demonstrated a way to detect life on other worlds...
  READ MORE

Solid buckyballs discovered in space
...Astronomers using NASA’s Spitzer Space Telescope have detected a particular type of molecule, given the nickname “buckyball”, in a solid form for the first time...
  READ MORE

Steamy water-world gets the Hubble treatment
...Hubble Space Telescope observations of a 7 Earth-mass planet find an unusual water-rich world swathed in a thick, steamy atmosphere...
  READ MORE








Star caught
consuming planet

DR EMILY BALDWIN
ASTRONOMY NOW
Posted: 20 May 2010


Bookmark and Share

According to new data collected by Hubble's Cosmic Origins Spectrograph (COS), the hottest known exoplanet in the Galaxy, WASP-12b, may also be the shortest lived, for it is being mercilessly consumed by its host star.

Astronomers already knew that WASP-12b was an oddity, orbiting its star so tightly that its atmosphere is superheated to some 2,200 degrees Celsius and the whole planet is contorted into an elongated rugby ball shape. Its swollen atmosphere has ballooned to three times Jupiter's radius and is swirling catastrophically into the star such that it may only have 10 million years left before it is completely devoured.

Artist concept of WASP-12b spilling into its host star. Gravitational forces due to the planet's proximity to the star have stretched the planet into an egg shape. Image: NASA, ESA, G. Bacon (STScI) and C. Haswell (The Open University, UK).

The exchange of matter between two stars is not unusual, but this is the first time it has been seen so clearly for a planet. “We see a huge cloud of material around the planet which is escaping and will be captured by the star,” says team leader Carole Haswell of The Open University. “We have identified chemical elements never before seen on planets outside our own Solar System.”

WASP-12b was discovered in 2008 by the SuperWASP (Wide Area Search for Planets) automated survey that searches for tiny dips in a stars' brightness as a planet passes in front of it. WASP-12b is so close to its star that it completes one orbit in just 1.1 days.

The sensitivity of Hubble's new COS instrument permitted measurements of the star's light at ultraviolet wavelengths that revealed absorption lines from elements such as aluminium, tin and manganese that become more pronounced as the planet transits the star, meaning that the elements exist in the planet's atmosphere as well as the star's. Furthermore, the fact that COS could detect these features at all suggests that the planet's heated atmosphere is highly extended.

In addition, COS measurements enabled astronomers to produce a light curve to show precisely how much of the star's light is blocked out during a transit event, which can be translated into the planet's radius. The planet is 40 percent more massive than Jupiter and its exosphere is so deformed that its radius exceeds its Roche lobe – the region of space around the planet within which material is gravitationally bound, and beyond which can escape onto the star, which is exactly what the Hubble observations confirm.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
 GET YOUR COPY

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
 GET YOUR COPY

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
 GET YOUR COPY


HOME | NEWS ARCHIVE | MAGAZINE | SOLAR SYSTEM | SKY CHART | RESOURCES | STORE | SPACEFLIGHT NOW

© 2014 Pole Star Publications Ltd.