The potassium absorption on HD189733b and HD209458b

Abstract

In this work, we investigate the potassium excess absorption around 7699Å of the exoplanets HD189733b and HD209458b. For this purpose, we used high spectral resolution transit observations acquired with the 2 × 8.4m Large Binocular Telescope (LBT) and the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI). For a bandwidth of 0.8Å, we present a detection > 7-σ with an absorption level of 0.18 % for HD189733b. Applying the same analysis to HD209458b, we can set 3-σ upper limit of 0.09%, even though we do not detect a K-excess absorption. The investigation suggests that the K-feature is less present in the atmosphere of HD209458b than in the one of HD189733b. This comparison confirms previous claims that the atmospheres of these two planets must have fundamentally different properties.

Probing the atmosphere of HD189733b with the Na i and K i lines

“…In this work, we spectrally resolve the atmospheric K I line on HD189733b from the observation presented by Keles et al (2019) and compare the line shape to the resolved Na I-D lines presented by Casasayas-Barris et al (2017). The alkali atoms Na and K are known to have very similar condensation curves as well as similar ionization potentials (Lavvas et al 2014), leading to very similarshaped mixing ratio profiles (Lavvas & Koskinen 2017).…”

“…A tentative 2.5-σ detection of K I in the atmosphere of HD189733b is shown by Pont et al (2013) where the Advanced Camera for Surveys instrument onboard of the Hubble Space Telescope (HST) was used for their observations. Recently, Keles et al (2019) detected K I with an excess level of 0.184 ± 0.022 per cent on HD189733b using the Large Binocular Telescope (LBT) and the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI).…”

Mass-loss rate and local thermodynamic state of the KELT-9 b thermosphere from the hydrogen Balmer series

“…achieved with sodium detections (Charbonneau et al 2002;Redfield et al 2008;Snellen et al 2008). Recent results suggest that high-resolution (typically λ/∆λ ∼ 10 5 ) transmission spectra of hot Jupiters probe their thermospheres, a key region of the upper atmosphere, in order to understand irradiated planets and allow us to achieve precise temperature and wind measurements because the lines (e.g., the Na I D doublet, the K I D doublet, the H I Balmer lines Hα, β, γ, the He I (2 3 S) triplet) are resolved and studies benefit from large signals (e.g., Wyttenbach et al 2015Wyttenbach et al , 2017Casasayas-Barris et al 2017, 2019Khalafinejad et al 2017Khalafinejad et al , 2018Seidel et al 2019;Yan & Henning 2018;Cauley et al 2019;Allart et al 2018Allart et al , 2019Nortmann et al 2018;Salz et al 2018;Alonso-Floriano et al 2019;Keles et al 2019;Chen et al 2020). Another landmark achievement obtained in the optical domain is the detection, with cross-correlation, of iron and other metals in the atmosphere of several ultra-hot Jupiters (Hoeijmakers et al 2018(Hoeijmakers et al , 2019Borsa et al 2019;Bourrier et al 2020a;Cabot et al 2020;Gibson et al 2020;Nugroho et al 2020;Stangret et al 2020;Ehrenreich et al 2020).…”

Is there Na I in the atmosphere of HD 209458b?

“…Finally, Keles et al (2019) studied the presence of K I in the atmosphere of HD 209458b. Interestingly, they reported an emission-like behaviour at low bandwidths, which would be consistent with the RM effect and non-detection of K I line at 7699 Å reported in this work.…”