If future space travelers get lost during a regional trek, they might pull out a map based on recently released data plotting the positions of almost all the stars within 32.6 light years of our sun.
“We are explorers,” says at the Carnegie Institution for Science in Washington, DC, who was not involved in the work. “We want to know our world and the first thing we do is check what our neighborhood looks like.”
This map of local space was produced by astronomers at the REsearch Consortium On Nearby Stars (RECONS). In 1994, they began investigating the nearest stars to find ones that remained undiscovered. They have steadily added stars to the local catalogue, including 44 new faint ones in their latest release. They now believe they’ve plotted 90 percent of all nearby stars.
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The RECONS team sifted through archival images taken years or decades apart to look for dim objects that appear to move against the background of distant stars. These often turn out to be unknown dwarf stars, most of which are too faint to be seen with the naked eye.
Cool, small stars
Using the Cerro Tololo Inter-American Observatory in Chile, they then took a closer look, photographing the objects at six-month intervals to study them in detail, determine if they’re stars, and precisely plot their distances from the sun.
Both techniques take advantage of an effect known as parallax, which causes distant objects to appear in slightly different places when viewed from different places in space – similar to how a distant object will appear to be further left or right as you close one eye or the other. A simple calculation allows astronomers to use parallax to determine the distance to nearby stars.
The majority of the newly-discovered objects are red dwarfs, faint cool stars smaller than our sun. This is exciting, says at the Harvard-Smithsonian Center for Astrophysics in Massachusetts, because such stars are likely to become targets in future observations hoping to discover exoplanets and extraterrestrial biosignatures.
“The characterization of the atmospheres of these planets to see if they’re habitable for life will only be possible for the very nearest ones,” she says.
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Read more: SETI looks at red dwarf stars in its search for ancient aliens
