Astronomers have created the first large-scale map that shows stellar ages in the Milky Way by determining the ages of nearly 100,000 red giant stars, at distances of up to 50,000 light-years from the galactic centre. Notably, the map confirms that our home galaxy has grown inside out: in the present epoch, most old stars can be found in the middle, more recently formed ones in the outskirts.
Researchers from Australia and the USA have discovered a distant, ancient cloud of gas that may contain the signature of the very first stars that formed in the universe. The gas cloud is many billions of light-years away from Earth, and is observed as it was just 1.8 billion years after the Big Bang.
The early universe was a chaotic mess of gas and matter that only began to coalesce into distinct galaxies hundreds of millions of years after the Big Bang. It would take several billion more years for such galaxies to assemble into massive galaxy clusters — or so scientists had thought. Now astronomers have detected a massive, sprawling, churning galaxy cluster that formed only 3.8 billion years after the Big Bang, some 10 billion light years from Earth.
Ripples in gas at the outer disc of our galaxy have puzzled astronomers since they were first revealed by radio observations a decade ago. Now, astronomers believe they have found the culprit — a dwarf galaxy, containing dark, unseen material, which skimmed the outskirts of the Milky Way a few hundred million years ago. This method to characterise dark matter marks first real application of galactoseismology.
Located about 7,500 light-years away in the southern constellation of Carina, Eta Carinae outshines our Sun by 5 million times. The binary system consists of two massive stars in a tight 5.5-year orbit, shrouded in an expanding veil of gas and dust from an enormous eruption seen in the 1840s. Now a study using archival data from NASA’s Spitzer and Hubble space telescopes has found five similar objects in other galaxies for the first time.
Astronomers are finding dozens of massive, so-called ‘runaway stars’ in our galaxy with the help of images from NASA’s Spitzer Space Telescope and Wide-field Infrared Survey Explorer, or WISE. When these speedy, massive stars plow through space, they can cause material to stack up in front of them, creating dramatic arc-shaped features called bow shocks.
NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, has captured the best high-energy X-ray view yet of a portion of the Andromeda Galaxy, our nearest large neighbouring spiral galaxy. The space observatory has observed 40 “X-ray binaries” — intense sources of X-rays comprising a black hole or neutron star that feeds off a stellar companion.
A detailed study of young stars and their surroundings has produced dramatic new evidence about how multiple-star systems form and how the dusty discs that are the raw material for planets grow around young stars. Scientists used the Very Large Array (VLA) radio telescope to study nearly 100 newborn stars in a cloud of gas and dust about 750 light-years from Earth.
In this season of post-Christmas gym memberships, black holes have shown that they too can lose a lot of the weight of the stars that surround them. One unusually star-deprived black hole at the site of two merged galaxies could provide new insight into black hole evolution and behaviour, according to observations with the Hubble Space Telescope and Chandra X-ray Observatory.
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