Broadband transmission spectroscopy of HD209458b with ESPRESSO: Evidence for Na, TiO, or both

Abstract

The detection and characterization of exoplanet atmospheres is currently one of the main drivers pushing the development of new observing facilities. In this context, high-resolution spectrographs are {proving} their potential and showing that high-resolution spectroscopy will be paramount in this field. We aim to make use of ESPRESSO high-resolution spectra, which cover two transits of HD209458b, to probe the broadband transmission optical spectrum of the planet. We applied the chromatic Rossiter-McLaughin method to derive the transmission spectrum of HD209458b. We compared the results with previous HST observations and with synthetic spectra. We recover a transmission spectrum of HD209458b similar to the one obtained with HST data. The models suggest that the observed signal can be explained by only Na, only TiO, or both Na and TiO, even though none is fully capable of explaining our observed transmission spectrum. Extra absorbers may be needed to explain the full dataset, though modeling approximations and observational errors can also be responsible for the observed mismatch. Using the chromatic Rossiter-McLaughlin technique, ESPRESSO is able to provide broadband transmission spectra of exoplanets from the ground, in conjunction with space-based facilities, opening good perspectives for similar studies of other planets.

Accepted for publication in A&A

References in corpus (27)

• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• ESPRESSO@VLT -- On-sky performance and first results
• Improved parameters for extrasolar transiting planets
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Nightside condensation of iron in an ultra-hot giant exoplanet
• Determining stellar macroturbulence using asteroseismic rotational velocities from Kepler
• The Very Low Albedo of an Extrasolar Planet: MOST Spacebased Photometry of HD 209458
• Detection of titanium oxide in the atmosphere of a hot Jupiter
• HST/STIS Optical Transit Transmission Spectra of the hot-Jupiter HD209458b
• The 4.5 $\mu$m full-orbit phase curve of the hot Jupiter HD 209458b
• TiO and VO broad band absorption features in the optical spectrum of the atmosphere of the hot-Jupiter HD209458b
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• A search for TiO in the optical high-resolution transmission spectrum of HD 209458b: Hindrance due to inaccuracies in the line database
• Rayleigh scattering by H2 in the extrasolar planet HD209458b
• Revisiting Proxima with ESPRESSO
• Advances in exoplanet science from Kepler
• PLATON II: New Capabilities And A Comprehensive Retrieval on HD 189733b Transit and Eclipse Data
• Highlights in the Study of Exoplanet Atmospheres
• A new class of Super-Earths formed from high-temperature condensates: HD219134 b, 55 Cnc e, WASP-47 e
• Rossiter--McLaughlin models and their effect on estimates of stellar rotation, illustrated using six WASP systems
• Evidence against a strong thermal inversion in HD 209458 b from high-dispersion spectroscopy
• Is there NaI in the atmosphere of HD 209458b? Effect of the centre-to-limb variation and Rossiter-McLaughlin effect in transmission spectroscopy studies
• Phase Offsets and the Energy Budgets of Hot Jupiters
• Near-ultraviolet Transmission Spectroscopy of HD 209458b: Evidence of Ionized Iron Beyond the Planetary Roche Lobe
• Improving transit characterisation with Gaussian process modelling of stellar variability
• Assessing Spectra and Thermal Inversions due to TiO in Hot Jupiter Atmospheres
• Stellar activity consequence on the retrieved transmission spectra through chromatic Rossiter-McLaughlin observations

Cited by in corpus (16)

• Stellar obliquities in exoplanetary systems
• A Preponderance of Perpendicular Planets
• The atmosphere of HD 209458b seen with ESPRESSO. No detectable planetary absorptions at high resolution
• CHEOPS geometric albedo of the hot Jupiter HD 209458b
• A Spectral Survey of WASP-19b with ESPRESSO
• Transmission spectroscopy of MASCARA-1b with ESPRESSO: Challenges of overlapping orbital and Doppler tracks
• HD22496b: the first ESPRESSO standalone planet discovery
• An ESPRESSO view of HD 189733 system. Broadband transmission spectrum, differential rotation, and system architecture
• CaRM: Exploring the chromatic Rossiter-McLaughlin effect. The cases of HD 189733b and WASP-127b
• Tentative detection of titanium oxide in the atmosphere of WASP-69 b with a 4m ground-based telescope
• Probing Na in giant exoplanets with ESPRESSO and 3D NLTE stellar spectra
• SOAPv4: A new step toward modeling stellar signatures in exoplanet research
• Characterization of exoplanetary atmospheres through a model-unbiased spectral survey methodology
• The GAPS programme at TNG LXVI. A homogeneous search for Na i and its possible variability in ten gas giant exoplanets
• Retrieving the transmission spectrum of HD 209458b using CHOCOLATE: A new chromatic Doppler tomography technique
• A Homogeneous Catalog of Rossiter-McLaughlin Systems: Distinct $e$-$\lambda$ Trends in Three Gas-Giant Mass Regimes