Abstract:
We present a transit-timing variation (TTV) and planetary atmosphere analysis of the Neptune-mass planet HAT-P 26 b. We present a new set of 13 transit light curves from optical ground-based observations and combine them
with light curves from the Wide Field Camera 3 on the Hubble Space Telescope, the Transiting Exoplanet Survey
Satellite, and previously published ground-based data. We refine the planetary parameters of HAT-P-26 b and
undertake a TTV analysis using 33 transits obtained over seven years. The TTV analysis shows an amplitude
signal of 1.98 ± 0.05 minutes, which could result from the presence of an additional ∼0.02 MJup planet at a 1:2
mean-motion resonance orbit. Using a combination of transit depths spanning optical to near-infrared wavelengths,
we find that the atmosphere of HAT-P-26 b contains -
+ 2.4 1.6
2.9% H2O with a derived temperature of -
+ 590 50
60 K.
