Planets Forming

ALMA image of the protoplanetary disc around HL TauriThis image from the Atacama Large Millimeter/submillimeter Array at the European Souther Observatory in Chile reveals extraordinarily fine detail that has never been seen before in the planet-forming disc around a young star, in this case, HL Tauri. This is one of the sharpest pictures ever made at submillimetre wavelengths. It’s an enormous step forward in the observation of how protoplanetary discs develop and how planets form.

HL Tauri’s disc appears much more developed than would be expected from the age of the system, suggesting that the planet-formation process may be faster than previously thought. Young stars are born in clouds of gas and fine dust which have collapsed under the effects of gravitation. The dense hot cores eventually ignite to become young stars. These young stars are initially cocooned in the remaining gas and dust, which eventually settles into a protoplanetary disc.

Image Credit: ESO


TW Hydrae rawThis picture was derived from observations made with the Hubble Space Telescope back in 2005 and shows a gap in a protoplanetary disk of dust and gas orbiting around a nearby red dwarf star called TW Hydrae. That star is 176 light-years away in the constellation Hydra (the Sea Serpent). Astronomers’ best guess about the cause of the gap is a growing, unseen planet which is gravitationally sweeping up material and forming a clear path through the disk. A masking device on the Hubble Space Telescope‘s Near Infrared Camera and Multi-Object Spectrometer was used to block the star’s light so that the disk’s structure could be seen. The observations show a 3 billion km wide gap that is not completely cleared out. The gap is around 65 billion km in diameter.

Image Credit: NASA