Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers detect the shadow of a water world in front of a nearby star

16.05.2007
A team of European astronomers leaded by Michaël Gillon, a researcher from Liege University, has measured the transit of a Neptune-sized planet around another star. For the first time, the size and density of such a small extra-solar planet is measured, showing that this planet is made up mainly of water.

The star GJ 436, a diminutive star (red dwarf) 30 light-years from the Sun, was known since 2004 to harbour a 22-Earth mass planet, orbiting 4 million kilometers from the star (0.03 Astronomical Units). Observations from the OFXB observatory in St-Luc, Switzerland, showed a periodic dimming of the star due to the passage of the planet in front of it. This event, called a transit, was subsequently confirmed with telescopes at the Wise Observatory in Israel, then precisely measured with the Euler telescope of Geneva University Observatory in Chile.

These measurements show that the planet has a diameter of about 50,000 km, four times that of the Earth. From the size and mass of the planet, the astronomers could infer that it is mainly composed of water. If the planet contained mostly hydrogen and helium – like Jupiter or Saturn – it would be much larger, and if it was made up of rock and iron like Earth, Mars and Venus, it would be much smaller. Michaël Gillon says : « This discovery is an important step towards the detection and study of Earth-like planets ».

This water world can either be surrounded by a light envelope of hydrogen and helium, like Neptune and Uranus, or be entirely surrounded by water, like most of Jupiter’s satellites. As the planet is close to its host star, its surface temperature is expected to be at least 300 C (600 F). The water in its atmosphere would therefore be in the form of steam. Inside, the water is crushed under intense pressure and adopts states unknown on Earth, except in physicist’s laboratories. Says Frédéric Pont : « water has more than a dozen solid states, only one of which is our familiar ice. Under very high pressure, water turns into other solid states denser than both ice and liquid water, just as carbon transforms into diamond under extreme pressures. Physicists call these exotic forms of water « Ice VII » and « Ice X ». If Earth’s oceans were much deeper, there would be such exotic forms of solid water at the bottom ». Inside GJ 436’s planet, this strange ice is moreover heated to many hundred degrees.

The detection of such a « hot ice world » has important consequences. It shows for the first time that planets similar to the « ice giants » Uranus and Neptune in our own Solar System exist at close distances from their star (the planet of GJ436 orbits every 2.6 days). Many of the planets of similar mass detected around other stars by the astronomers may therefore also be composed mainly of water. Some of them will have cooler temperatures, allowing the water on the surface to be liquid. Such planets covered by a single huge ocean have been dubbed « Ocean planets » by the specialists.

« The Corot satellite, which started operating at the beginning of this year, has among its main objectives to measure the size of planets like the one we just measured around GJ436, and even smaller. The Corot mission, to which astronomers from Geneva University are active participants, will allow a closer study of ocean planets and telluric planets like our own », says Didier Queloz.

Didier Moreau | alfa
Further information:
http://www.ulg.ac.be

More articles from Physics and Astronomy:

nachricht Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>