The solar neighborhood is so different than people imagine. But for the first time, we know what it’s like.
When you look up at the stars in the night sky, they appear with different brightnesses, colors, and clustering patterns. But when you see a star, you don’t immediately know whether it’s an isolated star or part of a multiple-star system, whether it’s intrinsically bright or intrinsically faint, and whether it’s nearby or far away. science space science cool science space and science universe space science
All you know, from a first inspection, is how bright and what color it appears to be. It turns out that most of the stars visible to the naked eye are actually intrinsically very bright, unusually blue, and quite far away. What about the closest stars? While a few of them are bright, nearby, and famous — like Alpha Centauri and Sirius — most of them require special equipment and techniques to find. science space science cool science space and science universe space science
In 1994, a team of astronomers formed RECONS, the REsearch Consortium On Nearby Stars, to investigate and learn about the nearest stars to Earth. They’ve just released their latest results; here are the highlights. science space science cool science space and science universe space science
What RECONS does is take the largest, faintest surveys it can of the entire sky, looking for objects that appear to show a parallax when viewed during different times throughout the year. As the Earth orbits the Sun, it changes its position relative to the other stars in the sky. science space science cool science space and science universe space science
Just like your thumb appears to move if you hold it at arm’s length and switch viewing it between your left eye and your right, so do the nearest stars move position relative to the more distant background stars when you view them six months apart. Measuring this parallax allows you to directly determine the distance to these stars, and the “nearest” ones are arbitrarily defined to be within 10 parsecs (32.6 light years), which corresponds to a parallax of 0.1″ or greater. Here are the six greatest finds, so far. science space science cool science space and science universe space science
1.) There are 316 discovered star systems within 10 parsecs. This is an incredible improvement over what we knew back at the start of RECONS; the number of known star systems within 10 parsecs was only 191; that number is now up to 316 today. The 125 new star systems that have been added by RECONS and other teams searching for nearby stars represents a 65% increase over the original figure. Additionally, we now have accurately measured parallaxes for all of them. These are all intrinsically faint systems, where of the 125: science space science cool science space and science universe space science
- 79 are dominated by red dwarfs,
- 37 by brown dwarfs, and
- 9 by “other” dwarfs such as white dwarf stars.
Many star systems have multiple members; “dominated by” means which class of star is the brightest, most luminous star in the system. With this latest data release, coverage has been so good, thorough, and deep, that the RECONS collaboration has announced that we have now, confidently, found more than 90% of all star systems within 10 parsecs. science space science cool science space and science universe space science