Space

July 31, 2013

NASA’s Chandra sees eclipsing planet in s-rays for first time

nasa-chandra

For the first time since exoplanets, or planets around stars other than the sun, were discovered almost 20 years ago, X-ray observations have detected an exoplanet passing in front of its parent star.

An advantageous alignment of a planet and its parent star in the system HD 189733, which is 63 light-years from Earth, enabled NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM Newton Observatory to observe a dip in X-ray intensity as the planet transited the star.

“Thousands of planet candidates have been seen to transit in only optical light,” said Katja Poppenhaeger of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who led a new study to be published in the Aug. 10 edition of The Astrophysical Journal. “Finally being able to study one in X-rays is important because it reveals new information about the properties of an exoplanet.”

The team used Chandra to observe six transits and data from XMM Newton observations of one.

The planet, known as HD 189733b, is a hot Jupiter, meaning it is similar in size to Jupiter in our solar system but in very close orbit around its star. HD 189733b is more than 30 times closer to its star than Earth is to the sun. It orbits the star once every 2.2 days.

HD 189733b is the closest hot Jupiter to Earth, which makes it a prime target for astronomers who want to learn more about this type of exoplanet and the atmosphere around it. They have used NASA’s Kepler space telescope to study it at optical wavelengths, and NASA’s Hubble Space Telescope to confirm it is blue in color as a result of the preferential scattering of blue light by silicate particles in its atmosphere.

The study with Chandra and XMM Newton has revealed clues to the size of the planet’s atmosphere. The spacecraft saw light decreasing during the transits. The decrease in X-ray light was three times greater than the corresponding decrease in optical light.

“The X-ray data suggest there are extended layers of the planet’s atmosphere that are transparent to optical light but opaque to X-rays,” said co-author Jurgen Schmitt of Hamburger Sternwarte in Hamburg, Germany. “However, we need more data to confirm this idea.”

The researchers also are learning about how the planet and the star can affect one another.

Astronomers have known for about a decade ultraviolet and X-ray radiation from the main star in HD 189733 are evaporating the atmosphere of HD 189733b over time. The authors estimate it is losing 100 million to 600 million kilograms of mass per second. HD 189733b’s atmosphere appears to be thinning 25 percent to 65 percent faster than it would be if the planet’s atmosphere were smaller.

“The extended atmosphere of this planet makes it a bigger target for high-energy radiation from its star, so more evaporation occurs,” said co-author Scott Wolk, also of CfA.

The main star in HD 189733 also has a faint red companion, detected for the first time in X-rays with Chandra. The stars likely formed at the same time, but the main star appears to be 3 billion to 3 1/2 billion years younger than its companion star because it rotates faster, displays higher levels of magnetic activity and is about 30 times brighter in X-rays than its companion.

“This star is not acting its age, and having a big planet as a companion may be the explanation,” said Poppenhaeger. “It’s possible this hot Jupiter is keeping the star’s rotation and magnetic activity high because of tidal forces, making it behave in some ways like a much younger star.”

The paper is available online at http://arxiv.org/abs/1306.2311.

 




All of this week's top headlines to your email every Friday.


 
 

 
Image courtesy of NASA/JPL-Caltech

NASA’s WISE spacecraft discovers most luminous galaxy in universe

Image courtesy of NASA/JPL-Caltech This artist’s concept depicts the current record holder for the most luminous galaxy in the universe. The galaxy, WISE J224607.57-052635.0, is erupting with light equal to more than 300 ...
 
 

Air Force launches hush-hush mini-shuttle into space

A mysterious space plane rocketed into orbit May 20, carrying no crew but a full load of technology experiments. The Air Force launched its unmanned mini-shuttle late morning, May 20. An Atlas V rocket lifted it up and out over the Atlantic. This is the fourth flight for the military research program, which is shrouded...
 
 
Image courtesy NASA TV

Critical NASA research returns to Earth aboard U.S. SpaceX Dragon spacecraft

Image courtesy NASA TV The SpaceX Dragon cargo spacecraft was released from the International Space Station’s robotic arm at 7:04 a.m., EDT, May 21. The capsule then performed a series of departure burns and maneuvers to ...
 

 

NASA, Canadian agency renew agreement to reduce aviation icing risks

On hand to sign the renewal agreement May 21 at the NRC offices in Ottawa, Ontario, were Jaiwon Shin, associate administrator of NASA’s Aeronautics Research Mission Directorate in Washington, and Ian Potter, the NRC’s vice-president of engineering. “The combined efforts of our two agencies will help solve some of the most difficult and challenging weather-related...
 
 
ULA photograph

Space and Missile Systems Center successfully launches the AFSPC-5 mission

ULA photograph An Atlas V rocket successfully launches the AFSPC-5 mission from Cape Canaveral Air Force Station, Fla., May 20, 2015.   The Air Force and its mission partners successfully launched the AFSPC-5 mission aboar...
 
 

NASA’s CubeSat initiative aids in testing of technology for solar sails in space

With help from NASA, a small research satellite to test technology for in-space solar propulsion launched into space May 20 aboard an Atlas V rocket from Cape Canaveral Air Force Station, Fla., as part of the agency’s CubeSat Launch Initiative. The Atlas V sent the U.S. Air Force’s X-37B space plane on its fourth mission,...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>