ESO’s SPHERE Instrument Sees Weird and Wonderful Dusty Disks around Young Stars
A series of images from the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument on ESO’s Very Large Telescope in Chile shows dusty disks of various shapes around nearby young stars.
The SPHERE instrument allows astronomers to suppress the brilliant light of stars in order to obtain a better view of the regions surrounding them.
Many of the young stars shown here come from a new study of T Tauri stars, a class of stars that are very young — less than 10 million years old — and vary in brightness.
The disks around these stars contain gas, dust, and planetesimals — the building blocks of planets and the progenitors of planetary systems.
These disks are wildly different in size and shape: some contain bright rings, some dark rings, and some even resemble hamburgers.
They also differ dramatically in appearance depending on their orientation in the sky, from circular face-on disks to narrow disks seen almost edge-on.
These images also show what our own Solar System may have looked like in the early stages of its formation, more than four billion years ago.
Most of the images presented were obtained as part of the Disks ARound T Tauri Stars with SPHERE (DARTTS-S) survey.
The distances of the targets ranged from 230 to 550 light-years away from Earth. For comparison, the Milky Way is roughly 100,000 light-years across, so these stars are very close to Earth.
But even at this distance, it is very challenging to obtain good images of the faint reflected light from disks, since they are outshone by the dazzling light of their parent stars.
Another new SPHERE observation is the discovery of an edge-on disk around the star GSC 07396-00759, found by the SpHere INfrared survey for Exoplanets (SHINE) survey.
This red star is a member of a multiple star system also included in the DARTTS-S sample but, oddly, this new disk appears to be more evolved than the gas-rich disk around the T Tauri star in the same system, although they are the same age.
This puzzling difference in the evolutionary timescales of disks around two stars of the same age is another reason why astronomers are keen to find out more about disks and their characteristics.
Along with data from other telescopes such as ALMA, they are revolutionizing astronomers’ understanding of the environments around young stars and the complex mechanisms of planetary formation.