Using data from the ESO’s Very Large Telescope (VLT), astronomers have been able to create the first weather map of the brown dwarf nearest to Earth at six light years away in the constellation Vela. The results about the weather on WISE J104915.57-531906.1B (nicknamed Luhman 16B) was submitted by lead author Ian Crossfield at the Max Planck Institut für Astronomie and appears in the January 30 edition of Nature.
Brown dwarfs are commonly regarded as failed stars, as they did not accumulate enough mass during formation to have a core capable of hydrogen fusion. They are smaller and cooler than our sun and do not emit much light. The VLT monitored Luhman 16B in infrared wavelengths and were able to observe the formation, duration, and dissipation of clouds as the brown dwarf rotated.
Astronomers noted that Luhman 16B (which is part of a binary pair with another brown dwarf) had variable levels of brightness that would change over the course of a few hours. It has already been known that brown dwarfs have dynamic weather, and it was announced earlier this month that the intense conditions include molten iron, salt, and hot sand raining down in the atmosphere. However, these storm clouds have never before been mapped.
Researchers used VLT’s CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) instrument to observe subtle changes in luminosity on the brown dwarf. CRIRES even allowed them to track the clouds and how they moved in relation to the telescope, indicating the direction of the storm as it progressed. Over time, researchers will be able to not only reliably track weather on brown dwarfs, but could be able to predict it as well.
Though brown dwarfs appear to have a lot in common with gas giants like Jupiter, there are some key differences. Brown dwarfs are 13-80 times more massive than our largest planet and have the ability to fuse deuterium, an isotope of hydrogen. However, the information that researchers are collecting on how to map weather on brown dwarfs can be directly applied to young gas giants, which is precisely what the Spectro-Polarimetric High-Contrast Exoplanet REsearch (SPHERE) instrument will be installed to do on the VLT later this year.