Washington: A new study has provided a deeper insight into the long-running hunt for super-Earths orbiting into the space.
NASA's Kepler spacecraft, which had launched on a planet-hunting mission in 2009, searched one small patch of the sky and identified more than 4,000 candidate exoplanets-worlds orbiting stars other than our own Sun. It was the first survey to provide a definitive look at the relative frequency of planets as a function of size.
Kepler's results suggest that small planets are much more common than big ones. Interestingly, the most common planets are those that are just a bit larger than Earth but smaller than Neptune-the so-called super-Earths.
There are no examples of super-Earths in our own solar system, despite being common in our local corner of the galaxy. Current observations suggested something about the sizes and orbits of the newly discovered worlds, but there is very little insight into their compositions.
Heather Knutson, assistant professor of planetary science at Caltech said, that where super-Earths appear to be the most common kind of exo-planet but we don't know what they're made of.
Knutson also articulated that these planets could have so many different compositions, and knowing their composition will tell a lot about how planets form, because planets in this size range acquire most of their mass by pulling in and incorporating solid material, water worlds initially must have formed far away from their parent stars, where temperatures were cold enough for water to freeze.
In addition to thinking about exoplanets, Knutson and her students use space-based observatories like the Hubble and Spitzer Space Telescopes to learn more about the distant worlds and its atmosphere at a number of different wavelengths, the researchers can determine which chemical compounds are present.
Till date, nearly two dozen planets have been characterized with this technique.
Super-Eaths like GJ 1214b and HD 97658b appeared to be surrounded by thick gases or clouds that continue to pose a real challenge in studies of super-Earths and these are also too small for Hubble and Spitzer to study.
With NASA's James Webb Space Telescope, which is scheduled for launch in 2018, will provide the first opportunity to study more Earth-like worlds.
The findings were published in the Astrophysical Journal.