280 & Counting -New Rocky ExoPlanet Discovered in Constellation Leo

A new, possible terrestrial-type planet, which lies at a distance of 30 light years from the Earth in the constellation of Leo, has a mass five times that of our planet but is the smallest planet found to date beyond our Solar System has been discovered by Spanish and UCL (University College London) scientists. One full day on the new planet would be equivalent to three weeks on Earth.

Computer simulations show that the exoplanet, dubbed GJ 436c, orbits its host star (GJ 436) in only 5.2 Earth days, and is thought to complete a revolution in 4.2 Earth days, compared to the Earth’s revolution of 24 hours and full orbit of 365 days.

The study, published in Astrophysical Journal, predicted the presence of a small exoplanet perturbing an inner planet, producing changes on its orbit. A re-analysis of archival radial velocities also permitted the identification of a signal that perfectly matches the simulations and corresponds to a planet in resonance with the inner one, meaning that for every two orbits of the known planet the new planet completes one.

Ignasi Ribas, lead author of the study, says: “After final confirmation, the new exoplanet will be the smallest found to date. It is the first one to be identified from the perturbations exerted on another planet of the system. Because of this, the study opens a new path that should lead to the discovery of even smaller planets in the near future, with the goal of eventually finding worlds more and more similar to the Earth.”

Before the 1990’s no one knew of a single planet orbiting a star other than our Sun. Since then the list of strange and exotic alien worlds has tallied up to around 300. As technological advancements and ultra-sensitive observatories become available, this list is expected to exponentially explode from the billions of exoplanets orbiting their stars in the universe.

In fact, new planet discoveries are becoming so common that we don’t even hear about many of them. Even some with exciting and notable features get passed by in the media hailstorm of planetary news. Some don’t even get any mention all outside of scientific circles.

"It's pretty routine now," said Alan Boss, a planet formation theorist at the Carnegie Institution of Washington. "Most planets that are found are not deemed worthy of a press release because they are sort of becoming 'one more planet.'"

All of these exosystems have been discovered by detecting the orbital motion of the star induced by its planet(s) - the planets cannot yet be seen directly because they are much fainter than their star and have too small an angular separation from it. With present technology, only giant like Jupiter and Saturn in our Solar System, can be detected - any Earth-mass planets would have too small an effect on their star's motion.

So, in case you missed any of the extraordinary extra-terrestrial news, here’s a list of 5 notable planets with a brief description and explanation of why they are newsworthy.

Epsilon Eridani b is the closest known extrasolar planet to our Earth. It orbits an orange Sun-like star only 10.5 light years away. This is close enough that astronomers believe it won’t be long before we can discover more details and take photographs using advanced telescopes.

SWEEPS-10 belongs to a new class of exoplanets called ultra-short-period planets (USPPs), which have orbits of less than a day. Sweeps-10 orbits its parent star from an incredibly close distance of around 740,000 miles. An entire year on the planet occurs every 10 hours!

Upsilon Andromeda b is tidally locked to its sun, similar to how the Moon is to Earth. One side of the planet is always facing its star. This causes the planet to be one of the most extreme surface environments astronomers have ever seen. One side of the planet is consistently hot as molten lava, while the other is always very cool, possibly below freezing.

HD 189733b was among the first planets to have its atmosphere identified. Astronomers determined that the planet is surrounded by thick clouds of silicates similar to grains of sand. While no water vapor was detected, scientists suspect it is hidden beneath the clouds.

Gliese 581 C, also called “Earth’s Twin” marked an exciting milestone in the search for alien life. It is the smallest exoplanet ever detected, and the first to lie within the habitable zone of its parent star. It is widely considered possibility that this planet could harbor alien life forms perhaps at the tribolyte level, perhaps at the level of ancient Rome, or perhaps even as far advanced machine-based intelligence.

The truly awe-inspiring concept behind all of these new planets is that we’ve barely touched the tip of the proverbial iceberg. Even more bizarrely foreign worlds and familiar earth-like planets are expected to emerge as technology develops. In our search for planets, reality may rapidly exceed our wildest dreams.

Dr Jean-Philippe Beaulieu, visiting astrophysicist at UCL Physics and Astronomy, says of GJ 436c in Leo: “This is the fourth super-Earth planet discovered. This planet is the hot twin of the frozen super-Earth (OGLE-2005-BLG-390lb) we discovered by microlensing two years ago. Other previously discovered planets of this class are the two hot super-Earths Gl 581b and Gl 876d detected by their Doppler wobble.“

Dr Giovanna Tinetti, UCL Physics and Astronomy who recently calculated the putative properties of this planet, says: “Calculations indicate that the temperature of the planet could be within 400-700 Kelvin [127-427 Celsius], but it could locally be as low as 350 K [77 C] at the poles, depending on the type of atmosphere.”

Most of the 280 or so planets discovered to date are gas giants similar to Jupiter, although some with masses below 10 times that of the Earth have already been found. Planets with masses of between one and 10 times the Earth are often dubbed super-Earths. In this case, current models predict that the new planet is a rocky type and has a radius some 50 per cent larger than the Earth.

Posted by Casey Kazan with Rebecca Sato.

 

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Comments

[knoxvilledaniel]

Are they able to use a spectrometer to identify atmospheric elements of GJ 436c ? It would be rather interesting to be able to tell if the atmosphere was earth - like, potentially earth - like, & so forth. These exo - planets seem to be appearing with amazing regularity.

[Ross Holder]

There's little doubt that within the next few years, we'll start finding Earth-like planets out there, but obviously determining the presence of intelligent life on them could be rather difficult. Still, I for one would be very excited to hear that a N/O2 atmosphere was found around a G main sequence star, falling between 0.7 and 2.0 Earth masses 0.9 to 1.1 AU from its central star. I just wish that the projects which could bring that day from "some future date" to now always seem to be suffering from chronic budget cuts. The loss of the Terrestrial Planet Finder (TPF) project was quite a blow; not to mention the Bush administration funnelling money out of key projects like the Space Interferometer (SIM; see http://en.wikipedia.org/wiki/Space_Interferometry_Mission for more info) into useless endeavours like Iraq has been. According to some recent research, in the last 2 years alone there has been nearly half a billion dollars in cuts to this kind of research affecting both NASA's space-based telescope programs to funding for Earth-bound projects like those a the Keck Observatory...