A stunning new image from the SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument on ESO’s Very Large Telescope (VLT) reveals the complex interplay of gas and dust expelled by two members of the stellar system AFGL 4106.
Tomassini et al. characterized the physical and morphological properties of the binary system AFGL 4106, which is composed of two evolved massive stars. Image credit: ESO / Tomassini et al.
“Before dying, stars expel huge amounts of gas and dust, ingredients for a growing nebula,” Dr. Gabriel Tomassini from the Observatoire de la Côte d’Azur and his colleagues said in a statement.
“The massive stars in the AFGL 4106 system shown here are at close yet distinct late stages of their lifecycles, with one having blown off enough mass to produce a dusty surrounding envelope.”
In their new paper, the authors mapped this debris and precisely characterized the central stars in AFGL 4106.
“Imaging astronomical objects close to stars poses a challenge due to the overpowering effect of a star’s brightness and, in fact, the stars themselves appear in black as their brightness saturated the detector of the instrument used to make this image,” they said.
“Fortunately, VLT’s SPHERE instrument is well equipped to deal with large contrasts in light levels, enabling a detailed study of both the high luminosity stars and the faint surrounding nebula for the first time.”
“Moreover, it can correct the blur caused by atmospheric turbulence, delivering very sharp images.”
The shape of the nebula reveals the significant impact the companion is having on the gas ejection of the dying star, introducing asymmetries and shifting the clouds of gas and dust away from a perfectly spherical shape.
“Our analysis sets constraints on the physical properties and evolutionary status of the system,” the astronomers concluded.
“This work contributes to our understanding of mass-loss processes in massive binaries and the shaping of nebulae around evolved stars.”
The results appear in the journal Astronomy & Astrophysics.
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G. Tomassini et al. 2026. Characterising the post-red supergiant binary system AFGL 4106 and its complex nebula with SPHERE/VLT. A&A 706, A5; doi: 10.1051/0004-6361/202557705
