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 Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun
18.04.2019 | University of Warwick

nachricht In vivo super-resolution photoacoustic computed tomography by localization of single dyed droplets
18.04.2019 | Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences

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: Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

A stellar flare 10 times more powerful than anything seen on our sun has burst from an ultracool star almost the same size as Jupiter

  • Coolest and smallest star to produce a superflare found
  • Star is a tenth of the radius of our Sun
  • Researchers led by University of Warwick could only see...

Im Focus: Quantum simulation more stable than expected

A localization phenomenon boosts the accuracy of solving quantum many-body problems with quantum computers which are otherwise challenging for conventional computers. This brings such digital quantum simulation within reach on quantum devices available today.

Quantum computers promise to solve certain computational problems exponentially faster than any classical machine. “A particularly promising application is the...

Im Focus: Largest, fastest array of microscopic 'traffic cops' for optical communications

The technology could revolutionize how information travels through data centers and artificial intelligence networks

Engineers at the University of California, Berkeley have built a new photonic switch that can control the direction of light passing through optical fibers...

Im Focus: A long-distance relationship in femtoseconds

Physicists observe how electron-hole pairs drift apart at ultrafast speed, but still remain strongly bound.

Modern electronics relies on ultrafast charge motion on ever shorter length scales. Physicists from Regensburg and Gothenburg have now succeeded in resolving a...

Im Focus: Researchers 3D print metamaterials with novel optical properties

Engineers create novel optical devices, including a moth eye-inspired omnidirectional microwave antenna

A team of engineers at Tufts University has developed a series of 3D printed metamaterials with unique microwave or optical properties that go beyond what is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

Fraunhofer FHR at the IEEE Radar Conference 2019 in Boston, USA

09.04.2019 | Event News

 
Latest News

New automated biological-sample analysis systems to accelerate disease detection

18.04.2019 | Life Sciences

Explosion on Jupiter-sized star 10 times more powerful than ever seen on our sun

18.04.2019 | Physics and Astronomy

New eDNA technology used to quickly assess coral reefs

18.04.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>