Astronomy and Astrophysics, volume 601A, 65-65 (2017/5-1)
Mid-infrared characterization of the planetary-mass companion ROXs 42B b.
DAEMGEN S., TODOROV K., SILVA J., HAND D., GARCIA E.V., CURRIE T., BURROWS A., STASSUN K.G., RATZKA T., DEBES J.H., LAFRENIERE D., JAYAWARDHANA R. and CORREIA S.
Abstract (from CDS):
We present new Keck/NIRC2 3-5µm infrared photometry of the planetary-mass companion to ROXS 42B in L', and for the first time in Brackett-α (Brff) and in Ms-band. We combine our data with existing near-infrared photometry and K-band (2-2.4µm) spectroscopy and compare these data with models and other directly imaged planetary-mass objects using forward modeling and retrieval methods in order to characterize the atmosphere of ROXS 42B b. The ROXS 42B b 1.25-5µm spectral energy distribution most closely resembles that of GSC 06214 B and κ And b, although it has a slightly bluer Ks-Ms color than GSC 06214 B and thus currently lacks evidence of a circumplanetary disk. We cannot formally exclude the possibility that any of the tested dust-free/dusty/cloudy forward models describe the atmosphere of ROXS 42B b well. However, models with substantial atmospheric dust/clouds yield temperatures and gravities that are consistent when fit to photometry and spectra separately, whereas dust-free model fits to photometry predict temperatures/gravities inconsistent with the ROXS 42B b K-band spectrum and vice-versa. Atmospheric retrieval on the 1-5µm photometry places a limit on the fractional number density of CO2 of log (n_CO2)<2.7, but provides no other constraints so far. We conclude that ROXS 42B b has mid-IR photometric features that are systematically different from other previously observed planetary-mass and field objects of similar temperature. It remains unclear whether this is in the range of the natural diversity of targets at the very young (∼2Myr) age of ROXS 42B b or unique to its early evolution and environment.
© ESO, 2017
stars: pre-main sequence - planets and satellites: individual: ROXS42Bb - planets and satellites: detection - planets and satellites: detection
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