A "super-Earth" has been discovered orbiting a red dwarf star on our cosmic doorstep, only 42 light years away. But here's the best bit: it's composed primarily of water, possibly in liquid form.
A "super-Earth" is an exoplanet (or "extra-solar planet") with a mass of 5-10 Earths. Only one other super-Earth has been confirmed (and a few more candidates have just been announced), the other 400 exoplanets we know of are many times bigger and are often referred to as "hot Jupiters" (many orbit very close to their host stars, getting roasted).
The race to find Earth-like planets around stars similar to our sun edged closer to a finish with the announcement on Monday that up to six "super-Earths" have been found orbiting sun-like neighbor stars.
The smallest of the bunch weighs in at about five times the mass of Earth and orbits a star known as 61 Virginis, which is visible with the naked eye in the constellation Virgo. The star is 28 light-years from Earth and closely resembles the sun in size, age and other attributes.
Two other newly detected planets -- each about the size of Neptune -- are part of 61 Virginis' family.
Another planet that is 7.8 times larger than Earth orbits HD 1461, a sun-like star located 76 light-years away in the constellation Cetus. Two sibling planets may orbit this same star, though confirmation is still pending, astronomer Gregory Laughlin, with the University of California's Lick Observatory, told Discovery News.
The race to find Earth-like planets around stars similar to our sun edged closer to a finish with the announcement on Monday that up to six "super-Earths" have been found orbiting sun-like neighbor stars.
The smallest of the bunch weighs in at about five times the mass of Earth and orbits a star known as 61 Virginis, which is visible with the naked eye in the constellation Virgo. The star is 28 light-years from Earth and closely resembles the sun in size, age and other attributes.
Two other newly detected planets -- each about the size of Neptune -- are part of 61 Virginis' family.
"I think this is really the tip of the iceberg," Laughlin said. "There's so many planets that have been detected now; it's completely clear that planets aren't rare. With our program, we've been focusing very intently on finding low-mass planets that orbit very nearby solar-type stars."[read more]
These are very exciting times for extrasolar planet hunters. Dozens of new exoplanets have been discovered (some a little larger than Earth, others several times the size of Jupiter) and astronomers are refining their already sophisticated techniques to analyze the composition of the atmospheres of these distant worlds.
Take exoplanet HD 209458b for example. It might not have the most romantic of names (the designation "HD 209458" is the catalogue number of the Sun-like star it's orbiting), but this exoplanet is famous in its own right. In 1999, it was the first ever transiting exoplanet to be discovered. A transiting exoplanet is a world that passes in front of its parent star when viewed from Earth, blocking a little of the starlight for astronomers to detect and measure.
By using the parent star's light to their advantage, NASA scientists have been able to decipher what chemicals HD 209458b's atmosphere contains even though it is 150 light years from Earth. This exoplanet is a very large gas giant which has a very tight orbit around the star (it is therefore dubbed a "Hot Jupiter"), so life isn't expected to be a possibility, but HD 209458b contains the basic organic chemicals as used, and produced, by life as we know it.[continue reading]
Naturally, the question of the potential for extraterrestrial life is bubbling, but the thick atmosphere of this super-Earth may be blocking out much of the star's light from reaching the surface.
Although this particular waterworld might not be suitable for habitation, the researchers who made this discovery think we're on the right track.
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