Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

European astronomers observe first evaporating planet

13.03.2003


Using the Hubble Space Telescope, for the first time, astronomers have observed the atmosphere of an extrasolar planet evaporating off into space. Much of this planet may eventually disappear, leaving only a dense core. The planet is a type of extrasolar planet known as a ’hot Jupiter’. These giant, gaseous planets orbit their stars very closely, drawn to them like moths to a flame.



The scorched planet called HD 209458b orbits ‘only’ 7 million kilometres from its yellow Sun-like star. By comparison, Jupiter, the closest gas giant in our Solar System, orbits 780 million kilometres from our Sun. The NASA/ESA Hubble Space telescope observations reveal a hot and puffed-up evaporating hydrogen atmosphere surrounding the planet. This huge envelope of hydrogen resembles a comet with a tail trailing behind the planet. The planet circles the parent star in a tight 3.5-day orbit. Earth also has an extended atmosphere of escaping hydrogen gas, but the loss rate is much lower.


A mainly European team led by Alfred Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS, France) is reporting this discovery in the March 13 NATURE Magazine. "We were astonished to see that the hydrogen atmosphere of this planet extends over 200 000 kilometres," says Vidal-Madjar.


Studying extrasolar planets, especially if they are very close to their parent stars, is not very easy because the starlight is usually too blinding. The planet was also too close to the star for Hubble to photograph directly in this case. However, astronomers could observe the planet indirectly since it blocks light from a small part of the star during transits across the disk of the star, thereby dimming it slightly. Light passing through the atmosphere around the planet is scattered and acquires a signature from the atmosphere. In a similar way, the Sun’s light is reddened as it passes obliquely through the Earth’s atmosphere at sunset. Astronomers used Hubble’s Space Telescope Imaging Spectrograph (STIS) to measure how much of the planet’s atmosphere filters light from the star. They saw a startling drop in the star’s hydrogen emission. A huge, puffed-up atmosphere can best explain this result.


What is causing the atmosphere to escape? The planet’s outer atmosphere is extended and heated so much by the nearby star that it starts to escape the planet’s gravity. Hydrogen boils off in the planet’s upper atmosphere under the searing heat from the star. "The atmosphere is heated, the hydrogen escapes the planet’s gravitational pull and is pushed away by the starlight, fanning out in a large tail behind the planet - like that of a comet," says Alain Lecavelier des Etangs working at the Institut d’Astrophysique de Paris, CNRS, France. Astronomers estimate the amount of hydrogen gas escaping HD 209458b to be at least 10 000 tonnes per second, but possibly much more. The planet may therefore already have lost quite a lot of its mass.
HD 209458b belongs to a type of extrasolar planet known as ‘hot Jupiters’. These planets orbit precariously close to their stars. They are giant, gaseous planets that must have formed in the cold outer reaches of the star system and then spiralled into their close orbits. This new discovery might help explain why ‘hot Jupiters’ so often orbit a few million kilometres from their parent stars. They are not usually found much closer than 7 million kilometres, as is the case for HD 209458b. Currently, the current closest distance is 5.7 million kilometres. Hot Jupiters have orbits that are as brief as 3 days, but not shorter. Perhaps the evaporation of the atmosphere plays a role in setting an inner boundary for orbits of hot Jupiters.

Franco Bonacina | alfa
Further information:
http://www.esa.int/export/esaCP/SEM6RO2A6BD_Expanding_0.html

More articles from Physics and Astronomy:

nachricht Artificial Intelligence Helps in the Discovery of New Materials
21.09.2016 | Universität Basel

nachricht Magnetic polaron imaged for the first time
19.09.2016 | Aalto University

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: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Chains of nanogold – forged with atomic precision

23.09.2016 | Life Sciences

New leukemia treatment offers hope

23.09.2016 | Health and Medicine

Self-assembled nanostructures hit their target

23.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>