Its been far too long since I contributed to Sky-Watching on a regular basis. On that sudden note here’s the first post in a while and its exoplanet related.
In the search for extraterrestrial life, NASA’s Kepler team have announced the discovery of Kepler-62 – a multiple planet system composed of five Earth and super-Earth sized planets, two of which are habitable zone worlds, orbiting an orange dwarf or to be precise a K-type main-sequence star.
Ok, so this is cool news right, and a K-type star too. I’m intrigued. Has Kepler found ideal SETI-target planets?
K-type stars are of particular interest in the search for other life because they are about three to four times as abundant as sun-like stars, making planet searches easier. K-type stars are also stable on the main sequence for a very long time, around 15 to 30 billion years which is two to three times longer than our own sun and this may create an opportunity for life to evolve on the terrestrial planets orbiting them.
The outermost planet, named Kepler-62f (see image) is about 1.4 times Earth’s radius and has a period of 267 Earth days. If Kepler-62f is a rocky planet with a similar atmosphere to Earth, sitting in the stars habitable zone it could host liquid water on its surface. Kepler-62e, also in the habitable zone is 1.6 times the Earth’s radius with a period of 122 Earth days, it could also host liquid water on its surface.
The authenticity of this multiple planet system was confirmed by a statistical analysis based on previous discoveries of multiple planets by Kepler as the detection of these planets was indirect. The Kepler astronomers observed gradual loss of the host star’s brightness due to the passage of a planet in the line of sight, and not the planets themselves. Speaking about the detection process Jason Rowe, Research Scientist at the Carl Sagan Center of the SETI Institute and co-author of the work said “Such calculations are only possible because of the thousands of additional transiting extrasolar planets that Kepler has discovered”.
About the discoveries Jon Jenkins, Senior Scientist at the Carl Sagan Center of the SETI Institute and co-author of the work said “These discoveries move us farther down the road to discovering planets similar to Earth. While we don’t know if Kepler-62e and f are rocky or whether they have liquid water pooling on their surfaces, their existence shows that the incidence of small worlds in the habitable zone of Sun-like stars is high.
Thus we can look forward to the discovery and detailed characterization of Earth’s cousins in the years and decades to come by future missions and telescopes.”
So there you go – exoplanets, K-type stars, some smart scientists from the SETI Institute, nice images and a post with a final thought…
If Kepler has found ideal SETI-target planets, sort the funding and bring on the future missions and telescopes.