StarDate 8/6/2014: Taking A Census Of Our Stellar Neighborhood
FROM THE UNIVERSITY OF TEXAS McDONALD OBSERVATORY, AS HEARD ON KCBS RADIO WEEKDAYS @ 9:52 A.M., 7:35 P.M. & 2:52 A.M.
STARDATE 8/6/2014: In a time when astronomers are studying galaxies that are billions of light-years away, you might think that we know everything there is to know about our own cosmic neighborhood. But that’s not the case. Astronomers are still discovering stars and other objects that are close by — neighbors that we didn’t even know were there.
Much of that work is being done by RECONS — the Research Consortium on Nearby Stars. It’s led by Todd Henry of Georgia State University. And it’s been going for 20 years.
The project uses a 36-inch telescope in Chile to look at objects that move across the sky quickly — an indication that they’re close by. Team members compare the positions of those objects to the background of more-distant stars when Earth is on opposite sides of the Sun. That allows them to measure the distances to those objects.
Initially, RECONS was looking for objects within 10 parsecs of Earth — about 33 light-years. A few years ago, the search was expanded to 25 parsecs — more than 80 light-years.
In its two decades of work, the search has yielded more than 300 previously uncharted systems inside that 25-parsec zone. The list includes dead stars known as white dwarfs, and failed stars known as brown dwarfs. But most of them are red dwarfs — the smallest and faintest of all stars. In fact, RECONS has found that roughly three-quarters of all the stars in our neighborhood are red dwarfs. We’ll have more about that tomorrow.