Author: Emily Conover / Source: Science News
Astronomers are going gaga over Gaia.
The April 25 release of data from the European Space Agency’s Gaia spacecraft, which cataloged nearly 1.7 billion stars, has kicked off a scientific spree, with multiple papers published online in the last two weeks at arXiv.org.
Charting stars in the Milky Way and beyond, Gaia surveys the entire sky. The spacecraft can measure stars’ motions and distances (SN Online: 4/25/18), properties which haven’t been inventoried on such a large scale before. “It’s really opening new dimensions in how we view stars,” says astronomer Ana Bonaca of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.
Because Gaia takes multiple images over time, “you’re not only getting a static picture of the sky at one instant, you’re looking at how it changes,” says astronomer Laura Watkins of the Space Telescope Science Institute in Baltimore. “We’ve never really had something like this before.”
Here are five new observations made with the unprecedented info.
1. Sizing up the Milky Way
Pinning down the mass of our home galaxy is a hefty challenge. Much of the Milky Way’s mass is hidden in the form of a dark matter halo, a shroud of matter that is invisible except for its gravitational pull. But scientists can gauge the galaxy’s unseen bulk by observing objects moving at the outskirts of the galaxy.
Combining information from Gaia and the Hubble Space Telescope, Watkins and colleagues estimated the galaxy’s mass using the motions of clumps of stars called globular clusters. The Milky Way is about 1.7 trillion times the mass of the sun, the team reports in a paper submitted April 30.
2. Rescaling exoplanets
Exoplanet updates are also on the agenda. Because NASA’s exoplanet-hunting Kepler telescope has limited ability in gauging how big stars are, the diameters of exoplanets passing in front of those stars were not well known (SN: 6/19/17). “Gaia has now completely changed the game and solved this problem,”…
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