September 18th, 2023
The ESO website publishes a new "Picture of the Week" on one of the Cobrex team’s results
The image shows the HIP 81208 star system observed by the Very Large Telescope (VLT) in Chile. HIP 81208 was thought to be a multiple system made up of a massive star (A, the bright central spot), a brown dwarf (B) orbiting A, and a low-mass star (C) located a little further away. However, a new study reveals a new object never observed before: a component Cb orbiting C and about 15 times more massive than Jupiter.
The discovery of Cb means that HIP 81208 is a peculiar system with two stars and two low-mass bodies orbiting each of these stars, in other words a quadruple hierarchical system.
The mass of the new Cb component places it on the borderline between planets and brown dwarfs, "failed" stars that are not massive enough and not hot enough to fuse hydrogen into helium.
The Cb component was discovered by a team led by A. Chomez, a doctoral student at Paris Observatory, by re-analysing archive data from the SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) instrument installed at the VLT. While most instruments use indirect methods to hunt for exoplanets, SPHERE uses direct imaging. Here we see a true image of this multiple system. It is the first hierarchical quadruple system to be discovered by direct imaging, and represents proof of the complexity of exoplanetary systems.
Link to Picture of the Week https://www.eso.org/public/images/p...
Credit:
ESO/A. Chomez et al.