ExoAtmospheres
IAC community database for exoplanet atmospheric observations
HAT-P-18 b
| Planet status | Confirmed |
|---|---|
| Planet type | Hot Jupiter |
| Period | 5.508029 d |
| Mass | 0.183 MJ 58.1574 M⊕ |
| Radius | 0.947 RJ 10.6064 R⊕ |
| Semi major axis | 0.0559 AU |
| Star name | HAT-P-18 |
| Star distance | 166 pc |
| Star teff | 4870 K |
| Star radius | 0.717 R☉ |
| Temperature (calculated) | 841 K |
| V | 12.76 mag |
| J | 10.822 mag |
| K | 10.234 mag |
| Alternate names | HAT-18b |
| Exoplanet Encyclopaedia |  |
Molecules
He+: Detection
|
JWST-NIRISS | Modeling tails of escaping gas in exoplanet atmospheres with Harmonica2025, Carlos Gascón, Mercedes López-Morales et al. |
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He: Detection H2O: Detection CO2: Detection Cloudy: Detection CH4: No detection
|
JWST-NIRISS | Near-Infrared Transmission Spectroscopy of HAT-P-18$\,$b with NIRISS: Disentangling Planetary and Stellar Features in the Era of JWST2023, Marylou Fournier-Tondreau, Ryan J. MacDonald et al. |
Also contains HST/WFC3 and Spitzer/IRAC transit observations |
Featureless spectra: Detection
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G-B: Low resolution visible | Featureless transmission spectra of 12 giant exoplanets observed by GTC/OSIRIS2023, C. Jiang, G. Chen et al. |
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He: Detection H2O: Detection
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JWST-NIRISS | Water and an escaping helium tail detected in the hazy and methane-depleted atmosphere of HAT-P-18b from JWST NIRISS/SOSS2022, Guangwei Fu, Néstor Espinoza et al. |
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He: Detection
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G-B:Low resolution IR | The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation2022, Shreyas Vissapragada, Heather A. Knutson et al. |
Narrow band photometry with Palomar/WIRC. Excess depth is 0.70±0.16% |
He: Detection
|
G-B:Low resolution IR | Metastable Helium Reveals an Extended Atmosphere for the Gas Giant HAT-P-18b2021, Paragas, Kimberly, Vissapragada, Shreyas et al. |
Using ultra-narrow band photometry |
H2O: Detection
|
HST WFC3 | A Population Study of Gaseous Exoplanets2018, Tsiaras, A., Waldmann, I. P. et al. |
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Rayleigh Scattering: Detection
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G-B: Low resolution visible | Rayleigh scattering in the transmission spectrum of HAT-P-18b2017, Kirk, J., Wheatley, P. J. et al. |
Rayleigh Scattering detection in HAT-P-18b.No Na/K detected. |