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.


 
 

 
ATK

ATK completes installation of world’s largest solid rocket motor for ground test

ATK The first qualification motor for NASA’s Space Launch Systems booster is installed in ATK’s test stand in Utah – ready for a March 11 static-fire test. NASA and ATK have completed installing the first Spac...
 
 
ULA photograph

Third Lockheed Martin-built MUOS satellite launched, responding to commands

ULA photograph The U.S. Air Force’s 45th Space Wing successfully launched the third Mobile User Objective System satellite, built by Lockheed Martin, for the U.S. Navy at 8:04 p.m. Jan. 20, 2015, from Launch Complex 41 at...
 
 
ULA photograph

ULA successfully launches Navy’s Mobile User Objective System-3

ULA photograph The U.S. Air Force’s 45th Space Wing successfully launched the third Mobile User Objective System (MUOS) satellite, built by Lockheed Martin, for the U.S. Navy at 8:04 p.m. Jan. 20, 2015, from Launch Comple...
 

 

Aerojet Rocketdyne Propulsion supports launch, flight of third MUOS satellite

Aerojet Rocketdyne played a critical role in successfully placing the third of five planned Mobile User Objective System (MUOS-3) satellites, designed and built by Lockheed Martin, into orbit for the U.S. Navy. The mission was launched from Cape Canaveral Air Force Station in Florida aboard a United Launch Alliance Atlas V rocket, with five Aerojet...
 
 
LM-MUOS-satellite

U.S. Navy poised to Launch Lockheed Martin-built MUOS-3 satellite

The U.S. Navy and Lockheed Martin are ready to launch the third Mobile User Objective System satellite, MUOS-3, from Cape Canaveral Air Force Station, Fla., Jan. 20 aboard a United Launch Alliance Atlas V rocket. The launch win...
 
 

NASA, NOAA find 2014 warmest year in modern record

https://www.youtube.com/embed/-ilg75uJZZU?enablejsapi=1&rel=0 The year 2014 ranks as Earth’s warmest since 1880, according to two separate analyses by NASA and National Oceanic and Atmospheric Administration scientists. The 10 warmest years in the instrumental record, with the exception of 1998, have now occurred since 2000. This trend continues a long-term warming of the planet, acc...
 




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>