The Bad Astronomer writes: "Astronomers have found the third-closest star system to the Earth: called WISE 1049-5319, it's a binary brown dwarf system just 6.5 light years away. Brown dwarfs are faint, low mass objects 13 — 75 times the mass of Jupiter, and are so dim they are very difficult to detect. These newly-found nearby objects were seen in observations from 1978 but went unnoticed at the time, but since that date the large apparent motion of the binary made their proximity obvious. Only two star systems are closer: Alpha Centauri (4.3 light years) and Barnard's star (6 light years)."
The Bad Astronomer writes: "A team of astronomers have announced the discovery of the smallest exoplanet orbiting a Sun-like star yet found: Kepler-37b, which has a diameter of only 3865 kilometers — smaller than Mercury, and only a little bigger than our own Moon. It was found using the transit method; as it orbits its star, it periodically blocks a bit of the starlight, revealing its presence. Interestingly, the planet has been known for some time, but only new advances in asteroseismology (studying oscillations in the star itself) have allowed the star's size to be accurately found, which in turn yielded a far better determination of the planet's diminutive size. Also, the asteroseismology research was not funded by NASA, but instead crowd funded by a non-profit, which raised money by letting people adopt Kepler target stars."
The Bad Astronomer writes: "A new study finds that there may be 100 billion alien planets in the Milky Way alone, with 17 billion of them the size of Earth. Announcements like this have been made before, but this new research is more robust than previous studies, using data from the Kepler planet-hunting spacecraft over a longer period and analyzing it in a more statistically solid way. They also found that smaller planets are not as picky about their host stars, with terrestrial planets forming around stars like the Sun or as small as tiny, cool red dwarfs with equal ease."
The Bad Astronomer writes: "Using Hubble Space Telescope, astronomers have spotted seven galaxies that are all over 13 billion light years away... including one that appears to be a record breaker at a staggering 13.3+ billion light years distant. That one is seen as it was only 380 million years after the Big Bang. This observation reaches into the era of the young cosmos when stars were first forming, and allows astronomers to better understand what the Universe was like back then — a time we know very little about."
The Bad Astronomer writes: "While nearly a thousand planets are known to orbit other stars, getting direct pictures of them is extremely difficult due to the glare from their host stars. Fewer than a dozen images of exoplanets exist. However, we can now add one more to the list: Kappa Andromedae b, or Kap And b for short. It's about 170 light years away, and orbits Kappa And, a massive star bright enough to see with the naked eye. One hitch: its mass puts it right at the upper limit for a planet, and it may edge into brown dwarf territory. Further observations are needed to pin its mass down."
The Bad Astronomer writes: "Astronomers have announced that the nearest star system in the sky — Alpha Centauri — has an Earth-sized planet orbiting one of its stars. Alpha Cen is technically a three-star system: a binary composed of two stars very much like the Sun, orbited by a third, a red dwarf, much farther out. Using the Doppler technique (looking for very small changes in the velocities of the stars) astronomers detected a planet orbiting the smaller of the two stars in the binary, Alpha Centauri B. The planet has a mass only 1.13 times that of the Earth, making it one of the smallest yet detected.However, it orbits the star only 6 million kilometers out, so it's far too hot to be habitable.
The signal from the planet is extremely weak but solidly detected, giving astronomers even greater hope of being able to find an Earth-like planet orbiting a star in its habitable zone."
The Bad Astronomer writes: "For the first time, a planet has been found in a stellar system composed of four stars. The planet, called PH-1, orbits a binary star made of two sun-like stars in a tight orbit. That binary is itself orbited by another binary pair much farther out. Even more amazing, this planet was found by two "citizen scientists", amateurs who participated in Planet Hunters, a project which puts Kepler Observatory data online for lay people to analyze. At least two confirmed planets have been found by this project, but this is the first — ever — in a quaternary system."
The Bad Astronomer writes: "Using the newly-commissioned ALMA radio observatory, astronomers have taken detailed images of one of the most amazing objects in the sky: the red giant R Sculptoris. As the star dies, it undergoes gigantic seizures beneath its surface that blast out waves of gas and dust from the surface. These normally expand into a spherical shell, but the presence of a nearby companion star changes things. The combined orbits of the two stars fling out the material like a garden sprinkler, forming enormous and incredibly beautiful spiral arms. Measuring the size and shape of the spiral shows the last eruption was 1800 years ago, lasted for nearly two centuries, and expelled enough material to make a thousand earths."
The Bad Astronomer writes: "A century ago, astronomers (including Edwin Hubble) discovered the Universe was expanding. Using the same methods — but this time with observations from an orbiting infrared space telescope — a new study confirms this expansion, and nails the rate with higher precision than done before. If you're curious, the expansion rate found was 74.3 +/- 2.1 kilometers per second per megaparsec — almost precisely in line with previous messureents."
The Bad Astronomer writes: "Astronomers have unveiled what may be the deepest image of the Universe ever created: the Hubble Extreme Deep Field, a 2 million second exposure that reveals galaxies over 13 billion light years away. The faintest galaxies in the images are at magnitude 31, or one-ten-billionth as bright as the faintest object your naked eye can detect. Some are seen as they were when they were only 500 million years old."
At the same time, the NEOCam (Near Earth Object camera) website went live today. This is a separate, publicly-funded space mission also designed to look for these asteroids. While Sentinel will concentrate on finding them and getting accurate positions and orbits, NEOCam will focus more on getting their physical characteristics. While not strictly competing with each other, they are more complementary; with both missions flying (in the 2017 time range) we will learn a huge amount about the asteroid threat from space."
The Bad Astronomer writes: "What's the nearest star to Earth that can explode as a supernova? Spica, at 260 light years away, is the nearest massive star that can explode, but IK Pegasi — a Sirius-like binary composed of a normal star and a white dwarf — will also one day blow. At a distance of 150 light years it's truly the closest supernova candidate. Happily, that's too far away to damage the Earth when it goes off — and it won't explode for millions of years at least, by which time it'll be even farther away. Either way, we're safe... for now."