Rings and gaps in a developing planetary system

The discovery of an exoplanet has most often resulted from the monitoring of a star's flicker (the transiting method) or its wobble (the radial velocity method). Discovery by direct imaging is rare because it is so difficult to spot a faint exoplanet hidden in the glare of its host star. The advent of the new generation of radio interferometers (as well as improvements in near-infrared imaging), however, has enabled the imaging of protoplanetary discs and, in the disc substructures, the inference of orbiting exoplanets. Gaps and ring-like structures are particularly fascinating clues to the presence or ongoing formation of planets.

Source

 

Credit: Dipierro et al. 2018

A model of the dust ring around the young star Elias 24, produced from simulations based on new ALMA millimeter images of the system. The model finds that the dust was shaped by a planet with 70% of Jupiter's mass located about 60 au from the star. Credit: Dipierro et al. 2018

Source / Image Courtesy

 

This video sequence starts with a wide-field view of the sky around the star Fomalhaut in the constellation of Piscis Austrinus (The Southern Fish). Fomalhaut is the brightest star in the constellation and one of the brightest stars known to have an orbiting planet.

It lies about 25 light-years from the Earth and is surrounded by a huge disc of dust. The final view of this video shows a new ALMA image of the disc (orange) and the new results from ALMA have given astronomers a major breakthrough in understanding a nearby planetary system and provided valuable clues about how such systems form and evolve. Note that ALMA has so far only observed a part of the ring. The underlying blue picture shows an earlier picture obtained by the NASA/ESA Hubble Space Telescope.