Understanding the puzzling nature of the ultracool brown dwarf HD 4113 C
The recently discovered coldest known brown dwarf companion HD4113C (Cheetham et al. 2017) has proven to be an enigmatic object, with an apparent discrepancy between its mass, age and temperature. This ultracool substellar companion appears to be too cold for its mass and age, presenting a challenge to brown dwarf cooling models. There are two scenarios that could answer this. Is the brown dwarf really that cold? Or is there another object in this system to account for the observed flux? We present the follow-up observations of this intriguing system to help answer some of these questions and provide further constraints on the orbital and physical parameters of HD4113C.