Category Astronomy/Space

Combined ALMA and VLA image of L1448 IRS3B system. Credit: Bill Saxton, ALMA (ESO/NAOJ/NRAO), NRAO/AUI/NSF

For the first time, astronomers have seen a dusty disk of material around a young star fragmenting into a multiple-star system. Scientists had suspected such a process, caused by gravitational instability, was at work, but new observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) revealed the process in action.

“This new work directly supports the conclusion that there are two mechanisms that produce multiple star systems – fragmentation of circumstellar disks, such as we see here, and fragmentation of the larger cloud of gas and dust from which young stars are formed,” said John Tobin, of the University of Oklahoma and...

These two natural color images from NASA’s Cassini spacecraft show the changing appearance of Saturn’s north polar region between 2012 and 2016.

Scientists are investigating potential causes for the change in color of the region inside the north-polar hexagon on Saturn. The color change is thought to be an effect of Saturn’s seasons. In particular, the change from a bluish color to a more golden hue may be due to the increased production of photochemical hazes in the atmosphere as the north pole approaches summer solstice in May 2017.

Researchers think the hexagon, which is a six-sided jetstream, might act as a barrier that prevents haze particles produced outside it from entering...

AG Carinae (AG Car) – an example of a Luminous Blue Variable (LBV) star. Credit: Judy Schmidt/Hubble Space Telescope.

A new study based on the first Gaia data release (DR1) reveals more accurate measurements of the distance of four canonical luminous blue variables (LBVs) in the Milky Way galaxy. DR1 contains a catalog of over 1 billion stars with precise measurements of their brightness and positions in the sky. These data were obtained by ESA’s Gaia satellite, which is completing the first-ever “galactic census”—the most detailed 3D map of the Milky Way ever made. The release of DR1 offers the scientific community an excellent opportunity to improve knowledge of our stellar environment and to redefine previous calculations.

Combing through the data obtained by Gaia, Nathan Smith of Uni...

Artist’s impression of Earth-sized planets orbiting a red dwarf star. Credit: @ NASA, ESA, and G.Bacon (STScI)

Computer simulations by astrophysicists at the University of Bern of the formation of planets orbiting in the habitable zone of low mass stars such as Proxima Centauri show that these planets are most likely to be roughly the size of Earth and to contain large amounts of water. In August 2016, the announcement of the discovery of a terrestrial exoplanet orbiting in the habitable zone of Proxima Centauri stimulated the imagination of the experts and the general public. After all this star is the nearest star to our sun even though it is 10X less massive and 500X less luminous...