Unifying High- and Low-resolution Observations to Constrain the Dayside Atmosphere of KELT-20b/MASCARA-2b

Abstract

We present high-resolution dayside thermal emission observations of the exoplanet KELT-20b/MASCARA-2b using the MAROON-X spectrograph. Applying the cross-correlation method with both empirical and theoretical masks and a retrieval analysis, we confirm previous detections of Fe\,\textsc{i} emission lines and we detect Ni\,\textsc{i} for the first time in the planet (at 4.7$\sigma$ confidence). We do not see evidence for additional species in the MAROON-X data, including notably predicted thermal inversion agents TiO and VO, their atomic constituents Ti\,\textsc{i} and V\,\textsc{i}, and previously claimed species Fe\,\textsc{ii} and Cr\,\textsc{i}. We also perform a joint retrieval with existing \textit{Hubble Space Telescope}/WFC3 spectroscopy and \textit{Spitzer}/IRAC photometry. This allows us to place bounded constraints on the abundances of Fe\,\textsc{i}, H${}_2$O, and CO, and to place a stringent upper limit on the TiO abundance. The results are consistent with KELT-20b having a solar to slightly super-solar composition atmosphere in terms of the bulk metal enrichment, and the carbon-to-oxygen and iron-to-oxygen ratios. However, the TiO volume mixing ratio upper limit (10${}^{-7.6}$ at 99\% confidence) is inconsistent with this picture, which, along with the non-detection of Ti\,\textsc{i}, points to sequestration of Ti species, possibly due to nightside condensation. The lack of TiO but the presence of a large H${}_2$O emission feature in the WFC3 data is challenging to reconcile within the context of 1D self-consistent, radiative-convective models.

arXiv comment14 pages, 9 figures, 2 tables

References in corpus (52)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b
• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres
• ExoMol molecular line lists XXX: a complete high-accuracy line list for water
• On the radiative equilibrium of irradiated planetary atmospheres
• A Possible Bifurcation in Atmospheres of Strongly Irradiated Stars and Planets
• 3D mixing in hot Jupiter atmospheres. I. application to the day/night cold trap in HD 209458b
• Can TiO Explain Thermal Inversions in the Upper Atmospheres of Irradiated Giant Planets?
• H- Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18 b
• ExoMol Molecular linelists -- XXXIII. The spectrum of Titanium Oxide
• Retrieving Temperatures and Abundances of Exoplanet Atmospheres with High-Resolution Cross-Correlation Spectroscopy
• Extremely Irradiated Hot Jupiters: Non-Oxide Inversions, H- Opacity, and Thermal Dissociation of Molecules
• HELIOS-K: An Ultrafast, Open-source Opacity Calculator for Radiative Transfer
• A solar C/O and sub-solar metallicity in a hot Jupiter atmosphere
• Atmospheric characterization of the ultra-hot Jupiter MASCARA-2b/KELT-20b
• Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere
• Irradiated Planets
• HELIOS-K 2.0 Opacity Calculator and Open-source Opacity Database for Exoplanetary Atmospheres
• Neutral Iron Emission Lines From The Day-side Of KELT-9b -- The GAPS Programme With HARPS-N At TNG XX
• A framework to combine low- and high-resolution spectroscopy for the atmospheres of transiting exoplanets
• Python Leap Second Management and Implementation of Precise Barycentric Correction (barycorrpy)
• Revisiting Proxima with ESPRESSO
• Where is the Water? Jupiter-like C/H ratio but strong H${}_2$O depletion found on $\tau$ Boötis b using SPIRou
• Titanium oxide and chemical inhomogeneity in the atmosphere of the exoplanet WASP-189b
• A New Window into Planet Formation and Migration: Refractory-to-Volatile Elemental Ratios in Ultra-hot Jupiters
• KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603
• Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b
• Searching for Thermal Inversion Agents in the Transmission Spectrum of MASCARA-2b/KELT-20b: Detection of Neutral Iron and Ionised Calcium H$\&$K Lines
• A unique hot Jupiter spectral sequence with evidence for compositional diversity
• The Influence of Host Star Spectral Type on Ultra-Hot Jupiter Atmospheres
• Detection of Fe I and Fe II in the atmosphere of MASCARA-2b using a cross-correlation method
• MASCARA-2 b: A hot Jupiter transiting the $m_V=7.6$ A-star HD185603
• EXOPLINES: Molecular Absorption Cross-Section Database for Brown Dwarf and Giant Exoplanet Atmospheres
• High-resolution Transmission Spectroscopy of MASCARA-2 b with EXPRES
• HyDRA-H: Simultaneous Hybrid Retrieval of Exoplanetary Emission Spectra
• Ground- and Space-based Detection of the Thermal Emission Spectrum of the Transiting Hot Jupiter KELT-2Ab
• Spatially-resolving the terminator: Variation of Fe, temperature and winds in WASP-76 b across planetary limbs and orbital phase
• On-sky commissioning of MAROON-X: A new precision radial velocity spectrograph for Gemini North
• Development and construction of MAROON-X
• Confirmation of Iron Emission Lines and Non-detection of TiO on the Dayside of KELT-9b with MAROON-X
• Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b
• A Search for FeH in Hot-Jupiter Atmospheres with High-Dispersion Spectroscopy
• Detection of CO emission lines in the dayside atmospheres of WASP-33b and WASP-189b with GIANO
• A survey of sodium absorption in ten giant exoplanets with high-resolution transmission spectroscopy
• Strong H${}_2$O and CO emission features in the spectrum of KELT-20b driven by stellar UV irradiation
• Exoplanet atmospheres at high resolution through a modest-size telescope. Fe II in MASCARA-2b and KELT-9b with FIES on the Nordic Optical Telescope
• The GAPS Programme at TNG XXXIII. HARPS-N detects multiple atomic species in emission from the dayside of KELT-20b
• Ab initio calculations to support accurate modelling of the rovibronic spectroscopy calculations of vanadium monoxide (VO)
• The GAPS programme at TNG XXX. Atmospheric Rossiter-McLaughlin effect and atmospheric dynamics of KELT-20b

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