Astronomers find super-Earth with the atmosphere

17.12.2009

More exoplanet! Today, astronomers announced the discovery of the so-called super-Earth near the neighboring low-mass star GJ1214.


The newly discovered planet has a mass about six times the mass of Earth, and its radius is 2.7 times larger, so it is somewhere between Earth and the ice giants of the Solar System — Uranus and Neptune. However, this exoplanet GJ1214b is something else: the atmosphere of a thickness of about 200 km. "This atmosphere is much thicker than Earth's, so the high pressure and absence of light eliminate life as we know it" — said David Charbonneau, lead author of that report the discovery in the journal Nature, — "but these conditions are still very interesting, unnecessarily . they allow the presence of a complex chemical composition. "

In addition, GJ1214b — a very hot place. It orbits the star with the rotational period of 38 hours at a distance of only two million kilometers — 70 times closer to the star than the Earth is to the Sun. "Being so close to its star, the planet must have a surface temperature of about 200 degrees Celsius, too hot for liquid water," — explained Charbonneau.

However, another member of the research team claims that the water may be present on GJ1214b, deep within the heart of the planet. "Despite the heat it seems, water world," — said shorted Bertha, who first noticed the signs of the planets in the data. "It is much smaller, cooler and more like Earth than any other known exoplanet."

The atmosphere was discovered when astronomers compared the resulting radius of GJ1214b with the theoretical model of the planets. They found that the radius exceeds the model calculations, and concluded that the thick atmosphere blocks the light from the star.

The planet was originally discovered as a transiting object within the project MEarth, which explores the 2000 low-mass stars in the search for extrasolar planets transit, and uses a series of small (16-inch) ground-based telescopes.

To confirm the planetary properties GJ1214b and get its mass (using the so-called Doppler method), the astronomers needed precision spectrograph HARPS, mounted on the 3.6-meter telescope at the European Southern Observatory in La Silla.

The next step will be to attempt to astronomers directly identify and characterize the atmosphere, which will require the help of space instruments such as NASA's Hubble Space Telescope. GJ1214b is located at a distance of only 40 light years from Earth, within the reach of existing observatories.
 

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