Atmospheres of massive planets and brown dwarfs as clue to distinguish between formation mechanisms
Short contributed talk abstract: How do we discriminate an exoplanet from a brown dwarf (BD)? This question has been fiercely debated considering definitions based on either their physical properties (like the mass or the ability to fuse deuterium) or their formation. BD usually are considered as failed stars, formed isolated or in hierarchical multiple systems. If formed as binary they might overlap in separation and mass with the population of giant planets formed in protoplanetary disks, but with a different atmospheric composition. Exploring the origin and nature of them can therefor potentially be approached by peering into the atmospheres of young, substellar (10 – 70  M_jup) objects. We intend to particularly study the carbon to oxygen ratio (C⁄O) together with the bulk properties and architectures. We analyze raw medium-resolution (R ~ 4000) SINFONI data in K-band (1.96 – 2.45 µm) from 24 young planetary-mass objects of spectral type between M5-L5. We applied the standard ESO SINFONI pipeline and used customized Python routines to further correct the data. Then we modeled the spectra with ForMoSA using different spectral grids. From the results we derived physical parameters as spectral type, effective temperature, gravity, metallicity and C/O ratio. This work provides NIR spectra and physical properties of various young planetary-mass objects which can be used as starting point to distinguish between the two populations by the imprints left on the spectra due to the formation process.