Mapping the surface of an extrasolar planet light years away.

Mapping the surface of an extrasolar planet light years away. From the paper’s abstract [pdf]:

We use archived Spitzer [Space Telescope] data of [the star] HD189733 … encompassing six transits, eight secondary eclipses, and a phase curve in a two-step analysis. The first step derives the planet-star system parameters. The second step investigates the structure found in eclipse scanning, using the previous planet-star system parameter derivation as Gaussian priors.

We find a 5-sigma deviation from the expected occultation ingress/egress shape for a uniform brightness disk, and demonstrate that this is dominated by large-scale brightness structure and not an occultation timing offset due to a non-zero eccentricity. Our analysis yields a 2D brightness temperature distribution showing a large-scale asymmetric hot spot whose finer structure is limited by the data quality and planet orbit geometry. [emphasis mine]

The Kepler team today announced the discovery of eleven new solar systems holding twenty-six planets.

Planets galore! The Kepler team today announced the discovery of eleven new solar systems holding twenty-six planets.

The planets orbit close to their host stars and range in size from 1.5 times the radius of Earth to larger than Jupiter. Fifteen of them are between Earth and Neptune in size, and further observations will be required to determine which are rocky like Earth and which have thick gaseous atmospheres like Neptune. The planets orbit their host star once every six to 143 days. All are closer to their host star than Venus is to our sun.

No Earths in the habitable zone quite yet, but we are circling in on our prey.

Astronomers have concluded that the stars in the Milky Way must average at least one planet per star.

Billions and billions! Astronomers have concluded that the stars in the Milky Way must average at least one planet per star. More importantly, the data says the galaxy should have billions of habitable planets.

[According to astronomer Uffe Gråe Jørgensen], a statistical analysis … shows that out of the Milky Way’s 100 billion stars, there are about 10 billion stars with planets in the habitable zone. This means that there may be billions of habitable planets in the Milky Way.

First Earth-sized planets found

Big news: The first Earth-sized planets have been found by Kepler.

The two planets, dubbed Kepler-20e and 20f, are the smallest planets found to date. They have diameters of 6,900 miles and 8,200 miles – equivalent to 0.87 times Earth (slightly smaller than Venus) and 1.03 times Earth. These worlds are expected to have rocky compositions, so their masses should be less than 1.7 and 3 times Earth’s.

Both worlds circle Kepler-20: a G-type star slightly cooler than the Sun and located 950 light-years from Earth. (It would take the space shuttle 36 million years to travel to Kepler-20.) Kepler-20e orbits every 6.1 days at a distance of 4.7 million miles. Kepler-20f orbits every 19.6 days at a distance of 10.3 million miles. Due to their tight orbits, they are heated to temperatures of 1,400 degrees Fahrenheit and 800 degrees F.

Once again, this is only the beginning. The announcement of an Earth in the habitable zone is only a matter of months away.