Astrophysics: Surprisingly fast motions in a dust disk
Nature 526, 7572 (2015). doi:10.1038/526204a
Authors: Marshall D. Perrin
A recently commissioned planet-finding instrument has been used to study a young solar system around the star AU Microscopii, leading to the discovery of rapidly moving features in the dust disk around the star. See Letter p.230
NASA narrows its list of planetary targets
Nature 526, 7572 (2015). http://www.nature.com/doifinder/10.1038/nature.2015.18482
Author: Alexandra Witze
Venus and asteroids take the spotlight as the agency chops list of Discovery-class candidates from 27 to 5.
Though astronomers have discovered thousands of planets orbiting other
stars, very little is known about how they are born. The conventional wisdom is
that planets coagulate inside a vast disk of gas and dust encircling newborn stars.
But the details of the process are not well understood because it takes millions of
years to happen as the disk undergoes numerous changes until it finally
The young, nearby star AU Microscopii (AU Mic) is an ideal candidate to get a snapshot of planet birthing because the disk is tilted nearly edge on to our view from Earth. This very oblique perspective offers an opportunity to see structure in the disk that otherwise might go unnoticed. Astronomers are surprised to uncover fast-moving, wave-like features embedded in the disk that are unlike anything ever observed, or even predicted. Whatever they are, these ripples are moving at 22,000 miles per hour fast enough to escape the star's gravitational pull. This parade of blob-like features stretches farther from the star than Pluto is from our sun. They are so mysterious it's not known if they are somehow associated with planet formation, or some unimagined, bizarre activity inside the disk.
Learn even more about AU Mic by joining the live Hubble Hangout discussion at 3:00 pm EDT on Thurs., Oct. 8 at http://hbbl.us/y6M.
Astrophysics: Primordial stars brought to light
Nature 526, 7571 (2015). doi:10.1038/526046a
Authors: Bethan James
The earliest stars are of huge importance to the chemical history of the cosmos, but have previously existed only in theory. There is now strong evidence that such population III stars exist in the brightest galaxy yet found in the early Universe.
The mountain-top battle over the Thirty Meter Telescope
Nature 526, 7571 (2015). http://www.nature.com/doifinder/10.1038/526024a
Author: Alexandra Witze
Plans to build one of the world's biggest telescopes on Mauna Kea in Hawaii are mired in conflict. Four people involved in the fight explain their diverse views.