Space Telescope Detects ExoPlanet Atmosphere

The latest issue of Science magazine carries a full feature on the intriguing news that NASA’s new exoplanet-hunting Kepler space telescope has detected the atmosphere of a known giant gas planet, demonstrating the telescope’s extraordinary scientific capabilities. The report is exciting for me because it’s another indication of how the search for life-bearing planets is cranking up as our ‘search tools’ become increasingly more sophisticated.The find is based on a relatively short 10 days of test data collected before the official start of science operations. Kepler was launched back in March and the observation demonstrates the extremely high precision of the measurements made by the telescope, even before its calibration and data analysis software were finished.

“As NASA’s first exoplanets mission, Kepler has made a dramatic entrance on the planet-hunting scene,” said Jon Morse, director of the Science Mission Directorate’s Astrophysics Division at NASA Headquarters in Washington. “Detecting this planet’s atmosphere in just the first 10 days of data is only a taste of things to come. The planet hunt is on!”

Kepler team members say these new data indicate the mission is indeed capable of finding Earth-like planets, if they exist. (It’s the kind of research our fictional characters in Ex Astris would find darn useful, for reasons that will become apparent as our story develops).
Kepler will spend the next three-and-a-half years searching for planets as small as Earth, including those that orbit stars in a warm zone where there could be water. It will do this by looking for periodic dips in the brightness of stars, which occur when orbiting planets transit, or cross in front of, the stars.

“When the light curves from tens of thousands of stars were shown to the Kepler science team, everyone was awed; no one had ever seen such exquisitely detailed measurements of the light variations of so many different types of stars,” said William Borucki, the principal science investigator and lead author of the paper.

The observations were collected from a planet called HAT-P-7, known to transit a star located about 1,000 light years from Earth. The planet orbits the star in just 2.2 days and is 26 times closer than Earth is to the sun. Its orbit, combined with a mass somewhat larger than the planet Jupiter, classifies this planet as a “hot Jupiter.” It is so close to its star, the planet is as hot as the glowing red heating element on a stove.

The Kepler measurements show the transit from the previously detected HAT-P-7. However, these new measurements are so precise, they also show a smooth rise and fall of the light between transits caused by the changing phases of the planet, similar to those of our moon. This is a combination of both the light emitted from the planet and the light reflected off the planet. The smooth rise and fall of light is also punctuated by a small drop in light, called an occultation, exactly halfway between each transit. An occultation happens when a planet passes behind a star.

The new Kepler data can be used to study this hot Jupiter in unprecedented detail. The depth of the occultation and the shape and amplitude of the light curve show the planet has an atmosphere with a day-side temperature of about 4,310 degrees Fahrenheit. Little of this heat is carried to the cool night side. The occultation time compared to the main transit time shows the planet has a circular orbit. The discovery of light from this planet confirms the predictions by researchers and theoretical models that the emission would be detectable by Kepler.

This new discovery also demonstrates Kepler has the precision to find Earth-size planets. The observed brightness variation is just one and a half times what is expected for a transit caused by an Earth-sized planet. Although this is already the highest precision ever obtained for an observation of this star, Kepler will be even more precise after analysis software being developed for the mission is completed.

“This early result shows the Kepler detection system is performing right on the mark,” said David Koch, deputy principal investigator of NASA’s Ames Research Center at Moffett Field, Calif. “It bodes well for Kepler’s prospects to be able to detect Earth-size planets.”

• More info about the Kepler Project on the NASA web site

Joint Mars Mission by NASA, ESA?

On 29th and 30th June, the ESA Director of Science and Robotic Exploration, David Southwood, met NASA’s Associate Administrator for Science, Ed Weiler, in Plymouth, UK, to establish a way for a progressive programme for exploration of the Red Planet. The outcome of the bilateral meeting was an agreement to create a Mars Exploration Joint Initiative (MEJI) that will provide a framework for the two agencies to define and implement their scientific, programmatic and technological goals at Mars.Discussions between ESA and NASA began last December, driven by the ESA Ministerial Council’s recommendation to seek international cooperation to complete the ExoMars mission and to prepare further Mars robotic exploration missions. At the same time, NASA was reassessing its Mars Exploration Program portfolio after the launch of its Mars Science Laboratory was delayed from 2009 to 2011.

This provided ESA and NASA with an opportunity to increase cooperation and expand collective capabilities. To investigate the options in depth, a joint ESA/NASA engineering working group was established, along with a joint executive board to steer the efforts and develop final recommendations on how to proceed.

At the bilateral meeting in Plymouth, the executive board recommended NASA and ESA establish MEJI spanning launch opportunities in 2016, 2018 and 2020, with landers and orbiters conducting astrobiological, geological, geophysical and other high-priority investigations, and leading to the return of samples from Mars in the 2020s. The Director and Associate Administrator agreed, in principle, to establish the Initiative and continue studies to determine the most viable joint mission architectures.

ESA and NASA also agreed to establish a joint architecture review team to assist the agencies in planning the mission portfolio. As plans develop, they will be reviewed by ESA member states for approval and by the US National Academy of Sciences. This unique collaboration of missions and technologies will pave the way for exciting discoveries at Mars.