CS Chamaeleontis

A massive circumbinary planet or low-mass brown dwarf detected in polarised light around the young binary star CS Chamaeleontis.

Ginski et al. "First direct detection of a polarized companion outside of a resolved circumbinary disk around CS Cha"
https://arxiv.org/abs/1805.02261

Press release :

http://spaceref.com/exoplanets/astronomers-photograph-possible-young-planet-by-chance.html

Astronomers Photograph Possible Young Planet by Chance

New analysis indicates that it is a star.

Haffert et al. "CS Cha B: A disc-obscured M-type star mimicking a polarised planetary companion"
https://arxiv.org/abs/2007.07831

Quote :

We determine the mass of the faint companion with several methods to be between 0.07 M_⊙ and 0.71 M_⊙ with an accretion rate of Ṁ=4×10^−11±0.4 Myr⁻¹. Conclusions. Our results show that CS Cha B is most likely a mid-M-type star that is obscured by a highly inclined disc, which has led to its previous classification using broadband NIR photometry as a planetary-mass companion.

However a circumbinary planet might well be out there...

The morphology of CS Cha circumbinary disk suggesting the existence of a Saturn-mass planet

Quote :

Planets have been detected in circumbinary orbits in several different systems, despite the additional challenges faced during their formation in such an environment. We investigate the possibility of planetary formation in the spectroscopic binary CS Cha by analyzing its circumbinary disk. The system was studied with high angular resolution ALMA observations at 0.87mm. Visibilities modeling and Keplerian fitting are used to constrain the physical properties of CS Cha, and the observations were compared to hydrodynamic simulations. Our observations are able to resolve the disk cavity in the dust continuum emission and the 12CO J:3-2 transition. We find the dust continuum disk to be azimuthally axisymmetric (less than 9% of intensity variation along the ring) and of low eccentricity (of 0.039 at the peak brightness of the ring). Under certain conditions, low eccentricities can be achieved in simulated disks without the need of a planet, however, the combination of low eccentricity and axisymmetry is consistent with the presence of a Saturn-like planet orbiting near the edge of the cavity.