Luhman 16

Binary pair of brown dwarfs ('failed stars'), third-closest star-like system, undiscovered until 2013.

What it is

Brown dwarf: Too light to ever start fusing. A star that failed to launch. Every kind of thing there is →

Can you see it?

Worth knowing about Luhman 16

In weight, each is only a few percent of the Sun's mass -- below the cutoff needed to ever ignite as a real star. On the 100-meter-track scale model of the Milky Way, Luhman 16 would be about 6-7 millimeters from the Sun -- roughly the size of a small pea. Light takes 6.5 Earth years to get here from Luhman 16, so what you are looking at is Luhman 16 as it was 6.5 Earth years ago.

How bright it is

So dim in visible light that despite being one of our nearest neighbors, it glows mostly in infrared heat rather than visible starlight.

What it is made of

Binary pair of brown dwarfs -- 'failed stars', too low in mass to ignite hydrogen fusion but too big/hot/round to be a planet.

How we know: Light spectrum shows methane and cool molecules only possible far below fusion temperatures; estimated mass is below the ~0.08 solar-mass fusion cutoff.

What makes it worth knowing

Third-closest star-like system to the Sun, yet undiscovered until 2013 because brown dwarfs are so faint.

Seen next to things you know

Next to it

The Milky Wayspiral galaxyNaked eyeProxima CentauristarWith effortAlpha Centauri A & Bbinary star systemNaked eyeSiriusstarNaked eyeVegastarNaked eyeArcturusstarNaked eye

Then go outside

Not this one. But the sky over your head is full of ones you can see, and the Planetarium knows which.