science & techESA/Hubble

Hubble tracks two brown dwarfs waltzing around each other six light-years away

the gist

Hubble has followed Luhman 16AB, a pair of brown dwarfs about six light-years from Earth, the third-closest stellar system to us after Alpha Centauri and Barnard's Star. The image is a stack of 12 exposures taken over three years, and an Italian-led team used high-precision astrometry to track how the two objects move across the sky and around each other. The pair orbit at roughly three times the Earth-Sun distance. Earlier ground-based observations had hinted at a planet tugging on them, but the Hubble data showed the two dwarfs are dancing alone.

so what

Brown dwarfs are objects too big to be planets but too small to ignite like stars, so precise orbital measurements of a nearby pair help pin down their masses. The result also shows how Hubble's precision can settle claims made by other telescopes.

fun fact

Luhman 16AB was only discovered in 2013, even though it is one of the closest star systems to the Sun.

ESA/Hubble · CC BY 4.0

Image: ESA/Hubble & NASA, L. Bedin et al.