The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars

Abstract

Transmission spectra probe exoplanetary atmospheres, but they can also be strongly affected by heterogeneities in host star photospheres through the transit light source effect. Here we build upon our recent study of the effects of unocculted spots and faculae on M-dwarf transmission spectra, extending the analysis to FGK dwarfs. Using a suite of rotating model photospheres, we explore spot and facula covering fractions for varying activity levels and the associated stellar contamination spectra. Relative to M dwarfs, we find that the typical variabilities of FGK dwarfs imply lower spot covering fractions, though they generally increase with later spectral types, from $\sim 0.1\%$ for F dwarfs to 2-4$\%$ for late-K dwarfs. While the stellar contamination spectra are considerably weaker than those for typical M dwarfs, we find that typically active G and K dwarfs produce visual slopes that are detectable in high-precision transmission spectra. We examine line offsets at H$\alpha$ and the Na and K doublets and find that unocculted faculae in K dwarfs can appreciably alter transit depths around the Na D doublet. We find that band-averaged transit depth offsets at molecular bands for CH${}_4$, CO, CO${}_2$, H${}_2$O, N${}_2$O, O${}_2$, and O${}_3$ are not detectable for typically active FGK dwarfs, though stellar TiO/VO features are potentially detectable for typically active late-K dwarfs. Generally, this analysis shows that inactive FGK dwarfs do not produce detectable stellar contamination features in transmission spectra, though active FGK host stars can produce such features and care is warranted in interpreting transmission spectra from these systems.

30 pages, 13 figures, 6 tables, accepted for publication in AJ

References in corpus (33)

• The NumPy array: a structure for efficient numerical computation
• The Transiting Exoplanet Survey Satellite
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• Measuring the rotation period distribution of field M-dwarfs with Kepler
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Rayleigh scattering in the transit spectrum of HD 189733b
• Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b: 1. the Transit
• Water Vapour Absorption in the Clear Atmosphere of an exo-Neptune
• An ultrahot gas-giant exoplanet with a stratosphere
• The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres
• HAT-P-26b: A Neptune-Mass Exoplanet with a Well Constrained Heavy Element Abundance
• A consistent retrieval analysis of 10 Hot Jupiters observed in transmission
• Detection of titanium oxide in the atmosphere of a hot Jupiter
• The Complete transmission spectrum of WASP-39b with a precise water constraint
• Weighing The Non-Transiting Hot Jupiter Tau BOO b
• ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
• Photometric Amplitude Distribution of Stellar Rotation of Kepler KOIs-Indication for Spin-Orbit Alignment of Cool Stars and High Obliquity for Hot Stars
• Placing the spotted T Tauri star LkCa 4 on an HR diagram
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• Sun-as-a-Star Spectrum Variations 1974-2006
• The variability of Sun-like stars: reproducing observed photometric trends
• The Starspots of HAT-P-11: Evidence for a Solar-like Dynamo
• On the tidal origin of hot Jupiter stellar obliquity trends
• spotrod: a semi-analytic model for transits of spotted stars
• Forecasting the Impact of Stellar Activity on Transiting Exoplanet Spectra
• Transiting the Sun: The impact of stellar activity on X-ray and ultraviolet transits
• Gemini/GMOS Transmission Spectral Survey: Complete Optical Transmission Spectrum of the hot Jupiter WASP-4b
• Spectral variability of photospheric radiation due to faculae I: The Sun and Sun-like stars
• Spatially resolved spectroscopy across stellar surfaces. I. Using exoplanet transits to analyze 3-D stellar atmospheres
• ACCESS: Ground-based Optical Transmission Spectroscopy of the Hot Jupiter WASP-4b
• Spatially resolved spectroscopy across stellar surfaces. II. High-resolution spectra across HD209458 (G0V)
• The GTC exoplanet transit spectroscopy survey VIII. Flat transmission spectrum for the warm gas giant WASP-80
• TOSC: an algorithm for the tomography of spotted transit chords

Cited by in corpus (74)

• The Featureless Transmission Spectra of Two Super-Puff Planets
• Updated Parameters and a New Transmission Spectrum of HD 97658b
• A Benchmark JWST Near-Infrared Spectrum for the Exoplanet WASP-39b
• A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
• A Spectral Survey of WASP-19b with ESPRESSO
• HST/WFC3 transmission spectroscopy of the cold rocky planet TRAPPIST-1h
• WASP-52b. The effect of starspot correction on atmospheric retrievals
• Gemini/GMOS Optical Transmission Spectroscopy of WASP-121b: signs of variability in an ultra-hot Jupiter?
• Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 $\mu$m
• Escaping Helium and a Highly Muted Spectrum Suggest a Metal-Enriched Atmosphere on Sub-Neptune GJ3090b from JWST Transit Spectroscopy
• Optical Transmission Spectroscopy of the Terrestrial Exoplanet LHS 3844b from 13 Ground-Based Transit Observations
• A roadmap for the atmospheric characterization of terrestrial exoplanets with JWST
• The GTC exoplanet transit spectroscopy survey XI. Possible detection of Rayleigh scattering in the atmosphere of the Saturn-mass planet WASP-69b
• Toward Robust Corrections for Stellar Contamination in JWST Exoplanet Transmission Spectra
• Evidence for Morning-to-Evening Limb Asymmetry on the Cool Low-Density Exoplanet WASP-107b
• Water absorption in the transmission spectrum of the water-world candidate GJ9827d
• Ground-Based Transmission Spectroscopy with FORS2: A featureless optical transmission spectrum and detection of H${}_2$O for the ultra-hot Jupiter WASP-103b
• LRG-BEASTS: sodium absorption and Rayleigh scattering in the atmosphere of WASP-94A b using NTT/EFOSC2
• Convolutional neural networks as an alternative to Bayesian retrievals
• ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of ${\mathrm{H}}_2\mathrm{O}$, but no evidence of Na or K
• Can 1D radiative equilibrium models of faculae be used for calculating contamination of transmission spectra?
• Spectral variability of photospheric radiation due to faculae II: Facular contrasts for cool main-sequence stars
• A transmission spectrum of the sub-Earth planet L98-59~b in 1.1-1.7 $\mu$m
• The metal-poor atmosphere of a Neptune/Sub-Neptune planet progenitor
• LRG-BEASTS: Ground-based Detection of Sodium and a Steep Optical Slope in the Atmosphere of the Highly Inflated Hot-Saturn WASP-21b
• An enhanced slope in the transmission spectrum of the hot Jupiter WASP-104b
• ACCESS: Confirmation of a Clear Atmosphere for WASP-96b and a Comparison of Light Curve Detrending Techniques
• Small-scale dynamo in cool main sequence stars. II. The effect of metallicity
• A new method to measure the spectra of transiting exoplanet atmospheres using multi-object spectroscopy
• Obliquity measurement and atmospheric characterization of the WASP-74 planetary system
• SAGE: A tool to constrain impacts of stellar activity on transmission spectroscopy
• Featureless transmission spectra of 12 giant exoplanets observed by GTC/OSIRIS
• Understanding Sun-as-a-star variability of solar Balmer lines
• Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
• Testing Earth-like atmospheric evolution on exo-Earths through oxygen absorption: required sample sizes and the advantage of age-based target selection
• First Comparative Exoplanetology Within a Transiting Multi-planet System: Comparing the atmospheres of V1298 Tau b and c
• Stability and detectability of exomoons orbiting HIP 41378 f, a temperate Jovian planet with an anomalously low apparent density
• The atmospheric composition of the ultra-hot Jupiter WASP-178 b observed with ESPRESSO
• A Panchromatic Characterization of the Evening and Morning Atmosphere of WASP-107 b: Composition and Cloud Variations, and Insight into the Effect of Stellar Contamination
• Testing the solar activity paradigm in the context of exoplanet transits
• Temperature-chemistry coupling in the evolution of gas giant atmospheres driven by stellar flares
• Stellar Models Also Limit Exoplanet Atmosphere Studies in Emission
• Fully fluorinated non-carbon compounds NF3 and SF6 as ideal technosignature gases
• An ESPRESSO view of HD 189733 system. Broadband transmission spectrum, differential rotation, and system architecture
• The Hubble/STIS Near-ultraviolet Transmission Spectrum of HD 189733b
• On the Effect of Stellar Activity on Low-resolution Transit Spectroscopy and the Use of High Resolution as Mitigation
• FUMES III: Ultraviolet and Optical Variability of M Dwarf Chromospheres
• Diversity in the haziness and chemistry of temperate sub-Neptunes
• A Population Analysis of 20 Exoplanets Observed from the Optical to the Near-infrared Wavelengths with HST: Evidence for Widespread Stellar Contamination
• Contemporaneous Observations of $H\alpha$ Luminosities and Photometric Amplitudes for M Dwarfs
• Cloudy mornings and clear evenings on a gas giant exoplanet
• A Low-mass, Pre-main-sequence Eclipsing Binary in the 40 Myr Columba Association -- Fundamental Stellar Parameters and Modeling the Effect of Star Spots
• Forward modelling of brightness variations in Sun-like stars -- II. Light curves and variability
• Possible Evidence for the Presence of Volatiles on the Warm Super-Earth TOI-270 b
• HST Transmission Spectra of the Hot-Neptune HD 219666 b: Detection of Water and the Challenge of Constraining Both Water and Methane
• ACCESS: Tentative detection of H${}_2$O in the ground-based optical transmission spectrum of the low-density hot Saturn HATS-5b
• An Analytic Characterization of the Limb Asymmetry -- Transit Time Degeneracy
• The Similar Seven: A set of very-alike exoplanets to test correlations between system parameters and atmospheric properties
• The Pandora SmallSat: A Low-Cost, High Impact Mission to Study Exoplanets and Their Host Stars
• Revisiting Kepler Transiting Systems: Unvetting Planets and Constraining Relationships among Harmonics in Phase Curves
• Using Doppler Imaging to model stellar activity and search for planets around Sun-like stars
• Quantifying the Impact of Starspot-Crossing Events on Retrieved Parameters from Transit Lightcurves
• Characterization of low-mass companions to $\text{Kepler}$ objects of interest observed with APOGEE-N
• Sensitivity to Sub-Io-sized Exosatellite Transits in the MIRI LRS Lightcurve of the Nearest Substellar Worlds
• MANGOS II: Five new giant planets orbiting low-mass stars
• Where does the simplified Stellar Contamination Model fail in Exoplanet Transmission Spectroscopy?
• The Hubble PanCET Program: A Featureless Transmission Spectrum for WASP-29b and Evidence of Enhanced Atmospheric Metallicity on WASP-80b
• Evidence for stellar contamination and water absorption in NGTS-5b's transmission spectra with GTC/OSIRIS
• Deciphering transmission spectra by exploring the solar paradigm
• Atmospheric asymmetries in WASP-121 b revealed by rotational transits detected with JWST
• A Panchromatic JWST Spectrum of a Giant Starspot on the Fully Convective M-dwarf TOI-3884
• KRONOS I: The $1-2.8\mu$m JWST Transmission Spectrum of the 23 Myr V1298 Tau c
• Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) on-sky demonstration with MagAO-X
• A new method to correct for host star variability in multi-epoch observations of exoplanet transmission spectra