Unveiling the Atmosphere of the Super-Jupiter HAT-P-14 b with JWST NIRISS and NIRSpec

Abstract We report the combined JWST Near Infrared Spectrograph (NIRSpec)/G395H and the Near Infrared Imager and Slitless Spectrograph (NIRISS)/Single Object Slitless Spectroscopy (SOSS) transmission spectrum of the transiting super-Jupiter HAT-P-14 b, from 0.60 to 5.14 μ m. Initial analysis of these data reported a near-featureless spectrum at NIRSpec wavelengths range (2.87–5.14 μ m) consistent with the small atmospheric scale height of the planet and unexplained bumps and wiggles at NIRISS wavelengths range (0.6–2.8 μ m). Here, we produce a self-consistent spectrum of HAT-P-14 b’s atmosphere with an up-to-date reduction. We detect H 2 O (3.09 σ ) both across NIRISS/SOSS wavelengths range and at the bluest end of NIRSpec/G395H as well as a gray cloud deck (1.90 σ ). We constrain the atmospheric metallicity of HAT-P-14 b to be roughly Solar, with [Fe/H] <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>0.0</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.98</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.89</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> , consistent with the planet mass–metallicity relationship. The differences compared to previous works are likely due to the improved STScI jwst pipeline, which highlights the need to reanalyze the early NIRISS/SOSS transiting exoplanet targets with the latest methods. As HAT-P-14 b is placed as the 805th best target for transmission spectroscopy according to Transmission Spectroscopy Metrics, our results showcase JWST’s unparalleled photometric precision which can easily characterize a thousand exoplanets’ atmospheres through transmission spectroscopy.