Aurora on a Dwarf Star

Astronomers have detected what looks like auroral emission on an ultra-cool star.

This artist conception shows an aurora over the polar region of a brown dwarf. Astronomers have detected auroral emission in both radio and optical wavelengths on the dwarf LSR J1835+3259. In J1835’s case, the aurora probably doesn’t sit over the rotational pole, because the auroral emission varies with the star’s rotation period, suggesting it rotates at least partially in and out of view. The team also doesn’t know what shape the dwarf star’s auroras take; they might be more like an arc or hotspot than a ring. Source: Sky & Telescope

Discovered jets of material ejected by still-forming young brown dwarfs

Astronomers using the Karl G. Jansky Very Large Array (VLA) have discovered jets of material ejected by still-forming young brown dwarfs. The discovery is the first direct evidence that brown dwarfs, intermediate in mass between stars and planets, are produced by a scaled-down version of the same process that produces stars.

Artist’s conception of a very young, still-forming brown dwarf, with a disk of material orbiting it, and jets of material ejected outward from the poles of the disk. Source: NRAO

CoRoT, the exoplanet hunter

CoRoT is a satellite devoted to the study of the internal structure of stars and to the hunt for planets outside the Solar System (exoplanets). It was launched on 27 december 2006, and the initial planned duration of the mission was 3 years.

An illustration showing the French astronomical satellite CoRoT. © CNES/DUCROS David, 2006

How to distinguish an ultra-cool brown dwarf from a giant planet

An international team of astronomers led by David Pinfield of the University of Hertfordshire has found a brown dwarf that is more than 99% hydrogen and helium. Described as ultra-cool, it has a temperature of just 400 degrees Celsius and its discovery could be a key step forward in helping astronomers distinguish between brown dwarfs and giant planets. The researchers publish their work in the journal Monthly Notices of the Royal Astronomical Society.

This artist's impression shows BD+01 2920B in the foreground (on the right hand side), with its host star in the background. The colour and banded atmosphere of the brown dwarf result from atmospheric gases and turbulence. Credit: J. Pinfield, for the RoPACS network at the University of Hertfordshire