ExoAtmospheres
IAC community database for exoplanet atmospheric observations
KELT-9 b
| Planet status | Confirmed |
|---|---|
| Planet type | UltraHot Jupiter |
| Period | 1.4811235 d |
| Mass | 2.88 MJ 915.264 M⊕ |
| Radius | 1.84 RJ 20.608 R⊕ |
| Semi major axis | 0.03368 AU |
| Star name | HD 195689 |
| Star distance | 204.455 pc |
| Star teff | 10170 K |
| Star radius | 2.36 R☉ |
| Temperature (calculated) | 3921 K |
| V | 7.56 mag |
| J | 7.458 mag |
| K | 7.482 mag |
| Alternate names | HD 195689 b |
| Exoplanet Encyclopaedia |  |
Molecules
H: Detection
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G-B: High resolution visible | Hydrogen airglow from an escaping ultrahot Jupiter atmosphere2026, Yapeng Zhang, Chenliang Huang et al. |
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Fe: Detection
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G-B: High resolution visible | Spinning out of focus: The challenge of rotational line broadening in exoplanet reflection spectroscopy2026, T. O. Winterhalder, K. Molaverdikhani et al. |
No detection of reflected light. Detection of Fe I planet emission as quality data check |
Fe: Detection Fe+: Detection Ca: Detection Ca+: Detection Ti: Detection Ti+: Detection Mg: Detection Si: Detection
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G-B: High resolution visible | Extreme winds on the emerging dayside of an ultrahot Jupiter2026, Yapeng Zhang, Joost P. Wardenier et al. |
Detection of dayside emission from transit to eclipse and detection of winds |
Fe+: Detection Mg+: Detection
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HST STIS | A High-Resolution NUV Transmission Spectrum of KELT-9b: Mg II and Fe II Escaping from the Hottest Known Giant Planet2025, Austin Baldwin, Joshua D. Lothringer et al. |
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Fe: Detection OH: Detection Molecular ratios: C/O, etc...: Detection
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G-B: High resolution visible | Detection of OH and Fe in the dayside atmosphere of the hottest ultra-hot Jupiter KELT-9b with SPIRou2025, Yuanheng Yang, Guo Chen et al. |
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Na: Detection
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G-B: High resolution visible | The GAPS programme at TNG LXVI. A homogeneous search for Na i and its possible variability in ten gas giant exoplanets2024, D. Sicilia, L. Malavolta et al. |
Study of the detection of Na through several transits. |
Fe+: Detection
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G-B: High resolution visible | The GAPS programme at TNG: TBD. Studies of atmospheric FeII winds in ultra-hot Jupiters KELT-9b and KELT-20b using HARPS-N spectrograph2024, M. Stangret, L. Fossati et al. |
Strong planetary winds detection |
H: Detection Na: Detection Ca: Detection Ca+: Detection Fe: Detection Fe+: Detection Mg: Detection Ti: Detection Sc: Detection Cr: Detection
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G-B: High resolution visible | The GAPS programme at TNG LX Atmospheric characterisation of KELT-9 b via single-line analysis: Detection of six H I Balmer lines, Na I, Ca I, Ca II, Fe I, Fe II, Mg I, Ti II, Sc II, and Cr II2024, M. C. D'Arpa, A. Saba et al. |
Detection of individual lines of several species. Study of the wind structure. |
TiO: Upper limit VO: Upper limit
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G-B: Low resolution visible | Low abundances of TiO and VO on the Dayside of KELT-9 b: Insights from Ground-Based Photometric Observations2024, Yuya Hayashi, Norio Narita et al. |
Low abundances of TiO and VO on the Dayside |
Albedo: 0.2 Phase curve: Yes Dayside Temperature (occultation): 4500 K |
Spitzer | A Comprehensive Analysis Spitzer 4.5 $μ$m Phase Curve of Hot Jupiters2024, Lisa Dang, Taylor J. Bell et al. |
Dayside and nightside temperatures from phase curve at 4.5 um. |
Ti+: Detection Fe: Detection Fe+: Detection Na: Detection Mg: Detection Na+: Detection Sc+: Detection
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G-B: High resolution visible | Small but mighty: High-resolution spectroscopy of ultra-hot Jupiter atmospheres with compact telescopes. KELT-9 b's transmission spectrum with Wendelstein's FOCES Spectrograph2023, N. W. Borsato, H. J. Hoeijmakers et al. |
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H: Detection Na: Detection Mg: Detection Ca+: Detection Sc+: Detection Ti+: Detection Cr+: Detection Fe: Detection Fe+: Detection Ca: Detection Cr: Detection Ni: Detection Sr+: Detection Tb+: Detection
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G-B: High resolution visible | The Mantis Network III: Expanding the limits of chemical searches within ultra hot-Jupiters. New detections of Ca I, V I, Ti I, Cr I, Ni I, Sr II, Ba II, and Tb II in KELT-9 b2023, N. W. Borsato, H. J. Hoeijmakers et al. |
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Si: Detection Mg+: Detection Ca: Detection
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G-B: High resolution visible | High-resolution Emission Spectroscopy of the Ultrahot Jupiter KELT-9b: Little Variation in Day- and Nightside Emission Line Contrasts2023, Andrew Ridden-Harper, Ernst de Mooij et al. |
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Fe: Detection Fe+: Detection Mg: Detection H: Detection
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G-B: High resolution visible | Multi-epoch detections of the extended atmosphere and transmission spectra of KELT-9b with a 1.5 m telescope2023, Nataliea Lowson, George Zhou et al. |
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H-: Detection
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HST WFC3 | A strong H- opacity signal in the near-infrared emission spectrum of the ultra-hot Jupiter KELT-9b2022, Bob Jacobs, Jean-Michel Désert et al. |
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Fe: Detection
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G-B: High resolution visible | The GAPS Programme at TNG. XLI. The climate of KELT-9b revealed with a new approach to high spectral resolution phase curves2022, L. Pino, M. Brogi et al. |
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H: Detection
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G-B: High resolution IR | Detection of Paschen $β$ absorption in the atmosphere of KELT-9 b: A new window into the atmospheres of ultra-hot Jupiters2022, A. Sánchez-López, L. Lin et al. |
Paschen β line absorption detection |
Na: Detection
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G-B: High resolution visible | A survey of sodium absorption in ten giant exoplanets with high-resolution transmission spectroscopy2022, Adam B. Langeveld, Nikku Madhusudhan et al. |
Confirmed the previously reported detections of Na using HARPS-N. |
TiO: Detection VO: Detection FeH: Detection H-: Detection
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HST WFC3 | Five key exoplanet questions answered via the analysis of 25 hot Jupiter atmospheres in eclipse2022, Quentin Changeat, Billy Edwards et al. |
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Fe+: Detection
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G-B: High resolution visible | Exoplanet atmospheres at high resolution through a modest-size telescope. Fe II in MASCARA-2b and KELT-9b with FIES on the Nordic Optical Telescope2022, Aaron Bello-Arufe, Lars A. Buchhave et al. |
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Fe+: Detection
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G-B: High resolution visible | Variable and super-sonic winds in the atmosphere of an ultra-hot giant planet2022, Anusha Pai Asnodkar, Ji Wang et al. |
We measure ∼10 km s−1 day-to-nightside winds traced by Fe II features in the planet's atmosphere |
O: Detection
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G-B: High resolution visible | High-resolution detection of neutral oxygen and non-LTE effects in the atmosphere of KELT-9b2021, Francesco Borsa, Luca Fossati et al. |
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Fe: Detection TiO: Upper limit
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G-B: High resolution visible | Confirmation of Iron Emission Lines and Non-detection of TiO on the Dayside of KELT-9b with MAROON-X2021, David H. Kasper, Jacob L. Bean et al. |
Fe detected in emission |
H: Detection
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G-B: High resolution visible | Mass-loss rate and local thermodynamic state of the KELT-9 b thermosphere from the hydrogen Balmer series2020, Wyttenbach, A., Mollière, P. et al. |
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Fe: Detection
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G-B: High resolution visible | Neutral Iron Emission Lines from the Dayside of KELT-9b: The GAPS Program with HARPS-N at TNG XX2020, Pino, Lorenzo, Désert, Jean-Michel et al. |
The first detection of atomic emission lines from the atmosphere of an exoplanet. FeI in emission with HARPS-N |
Phase curve: Yes |
Spitzer | Evidence for H2 Dissociation and Recombination Heat Transport in the Atmosphere of KELT-9b2020, Mansfield, Megan, Bean, Jacob L. et al. |
Spitzer 4.5 micron phase curve showing evidence for H2 dissociation/recombination |
Ca+: Detection
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G-B: High resolution IR | Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b2019, F. Yan, N. Casasayas-Barris et al. |
Using transit observations with CARMENES and HARPS-N |
Na: Detection Cr+: Detection Sc+: Detection Y+: Detection Mg: Detection Fe: Detection Fe+: Detection Ti+: Detection
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G-B: High resolution visible | A spectral survey of an ultra-hot Jupiter. Detection of metals in the transmission spectrum of KELT-9 b2019, Hoeijmakers, H. J., Ehrenreich, D. et al. |
Alternative name KELT-9b.Evidences of Ca i, Cr i, Co i, and Sr ii using transit observations with HARPS-N. |
He: Upper limit
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G-B: High resolution IR | Ground-based detection of an extended helium atmosphere in the Saturn-mass exoplanet WASP-69b2018, Lisa Nortmann, Enric Pallé et al. |
He analysis in the appendix |
Fe: Detection Fe+: Detection Ti+: Detection
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G-B: High resolution visible | Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b2018, Hoeijmakers, H. Jens, Ehrenreich, David et al. |
Detection of iron (Fe and Fe+) and Ti+ via the cross-correlation technique using HARPS-N transit observations |
H: Detection
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G-B: High resolution visible | An extended hydrogen envelope of the extremely hot giant exoplanet KELT-9b2018, Yan, FeiHenning, Thomas |
Detection of Hα with transmission spectroscopy |
C: Detection Si: Detection K: Detection Tb+: No detection H: Detection V+: Detection Co: Detection Na: Detection Ca: Detection Ca+: Detection Sc: Detection O: Detection Ti: Detection Ti+: Detection Cr: Detection Cr+: Detection Mg: Detection V: Detection Mn: Detection Fe: Detection Fe+: Detection Ni: Detection Ni+: Detection Sr+: Detection Y+: Detection Ba+: Detection
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G-B: High resolution visible | Astro-ph arXiv:2609.10695 | Combined analysis of 13 transits detects 29 species, including Zr II, La II, Pr II, and Nd II. |
Molecular ratios: C/O, etc...: Detection
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G-B: High resolution visible | Astro-ph arXiv:2609.13051 |