Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

First ground-based detection of light from transiting exoplanets

15.01.2009
Transiting exoplanets are routinely detected when they pass in front of their parent star as viewed from the Earth, which only happens by chance.

The transit event causes a small drop in the observed starlight, which can then be detected. Fifty-five exoplanets have been detected this way since the observation of the first transiting planet HD 209458 b in 1999.

When the planet revolves around its star or when it goes behind, the light coming from the system also varies, though the resulting smaller modulation is much harder to detect. This is mostly due to the small amount of light emitted by these exoplanets which are believed to be as dark as coal and reflect little of the incoming starlight. Fortunately, some of these planets are very hot, thus emitting light, mostly at infrared wavelengths.

Up to now, detections of this kind have only been made using the Spitzer infrared space telescope. This week, Astronomy & Astrophysics is publishing the two first ground-based detections of thermal emission from transiting, hot-Jupiter exoplanets, from two independent teams of astronomers that used different approaches.

One team includes Ernst De Mooij and Ignas Snellen (University of Leiden, Netherlands) who used the William Hershel 4.2 meter telescope in La Palma (Canary Islands, Spain) to observe the star TrES-3 and its planet TrES-3b. To be able to detect the light coming from the planet, they observed the planet exactly at the time when it passes behind the star. They observed the event at infrared wavelengths, where the planet is at its brightest compared to the star (even if the planet is still much fainter than the star!) As they detected the light coming from the planet, they estimated the temperature of its atmosphere to about 2000 Kelvins. This indicates that the day side of the planet is extremely hot.

The other team, involving David Sing (IAP, France) and Mercedes Lopez-Morales (Carnegie Institution of Washington, USA), had a different approach. They looked at a much fainter star and its planet, OGLE-TR-56b. This planet is one of the most irradiated planets known so far, both because the planet is very close to the star and because the star is very hot. To detect the slight modulation in light that occurs when the planet passes behind its star, they used the 8 meter Very Large Telescope (ESO, Chile) and the 6.5 meter Magellan Telescopes (Las Campanas, Chile) and were able to observe this event at visible wavelengths. Indeed, the planet OGLE-TR-56b is heated so much by its star that it emits detectable amounts of light in the visible wavelengths, and not only in the infrared as TrES-3b does. Hence, Sing and Lopez-Morales measured the record-high temperature of a planetary atmosphere: 2700 Kelvins. As in the case of TrES-3b, such a high day-side temperature indicates that winds cannot redistribute the heat efficiently from the day side to the night side.

These two independent results are very interesting for astronomers and planetary scientists because they allow a direct probe of the temperature of these planetary atmospheres, and because they show that such measurements can be made from ground-based observatories, and not only when using space telescopes.

Jennifer Martin | alfa
Further information:
http://www.aanda.org/content/view/355/42/lang,en/

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 >>>