Hubble Spots Waltzing Dwarfs

This seemingly unspectacular series of dots with varying distances

between them actually shows the slow waltz of two brown dwarfs. The

image is a stack of 12 images made over the course of three years with

the NASA/ESA Hubble Space Telescope. Using high-precision astrometry, an

Italian-led team of astronomers tracked the two components of the

system as they moved both across the sky and around each other.

  

The

observed system, Luhman 16AB, is only about six light-years away and is

the third closest stellar system to Earth — after the triple star

system Alpha Centauri and Barnard’s Star. Despite its proximity, Luhman

16AB was only discovered in 2013 by the astronomer Kevin Luhman. The two

brown dwarfs that make up the system, Luhman 16A and Luhman 16B, orbit

each other at a distance of only three times the distance between the

Earth and the sun, and so these observations are a showcase for Hubble’s

precision and high resolution.

The astronomers using Hubble to

study Luhman 16AB were not only interested in the waltz of the two brown

dwarfs, but were also searching for a third, invisible, dancing

partner. Earlier observations with the European Southern Observatory's

Very Large Telescope indicated the presence of an exoplanet in the

system. The team wanted to verify this claim by analyzing the movement

of the brown dwarfs in great detail over a long period of time, but the

Hubble data showed that the two dwarfs are indeed dancing alone,

unperturbed by a massive planetary companion.