A group of European scientists hopes to study the atmospheres of exoplanets using a tiny telescope placed in low-Earth orbit for a period of three to four years.
Dubbed the Twinkle satellite, that telescope, if launched, would observe in the infrared, looking for heat signatures in the atmospheres of at least 100 exoplanets within several hundred light years of our own solar system.
Astrophysicist Giovanna Tinetti of London’s University College believes this can be done successfully with a 20-inch (50 cm) mirror.
That stands in sharp contrast to the Hubble Space Telescope, which has a mirror of eight feet (2.4 meters).
A new generation of powerful large telescopes, starting with the James Webb Space Telescope scheduled for launch in 2018, will be put into use within the next decade to answer questions about the composition and atmospheres of exoplanets, with the specific task of deeming whether they are habitable.
But those telescopes are much more expensive than Twinkle, which the European scientists believe would cost $79 million.
“We have identified a niche of science that could be done very well even with a relatively more modest instrument,” Tinetti said.
Nearby Earth-like exoplanets give off strong infrared signatures from which astronomers using Twinkle could identify molecules, weather, and climate, he added.
Getting Twinkle launched depends on the scientists obtaining sufficient funding for the project.
A 2011 proposal Tinetti and colleagues presented to the European Space Agency (ESA) in 2011 would have sent a larger telescope to the Lagrangian Point 2, located 932,000 miles (1.5 million km) from Earth to study exoplanets.
That project, titled EChO, would have cost $0.57 billion. ESA did not select it for funding.
Unlike EChO, Twinkle will not be sent to a Lagrangian point; it is smaller and has a more limited wavelength range. The proposal calls for building it using commercial off-the-shelf components.
Tinetti’s team envision Twinkle being used in collaboration with international science groups.
One commercial spaceflight company, Surrey Satellite Technology, Ltd, is already on board in partnering with the Twinkle project.
The researchers hope to observe a range of emissions, both visible and infrared, from exoplanets orbiting very bright stars. These planets are not priorities for either the James Webb Space Telescope or the Spitzer Space Telescope.
A secondary goal involves using Twinkle for educational outreach to students in grades K-12.
An ideal candidate for Twinkle is 55 Cancri e, which orbits a Sun-like star so close that its temperature is 3,700 degrees Fahrenheit (2,300 degrees Celsius). While far too hot to sustain life, this planet might host a carbon-rich interior.