A Featureless Infrared Transmission Spectrum for the Super-Puff Planet Kepler-79d

Abstract

Extremely low density planets ('super-puffs') are a small but intriguing subset of the transiting planet population. With masses in the super-Earth range ($1-10$ M${}_{\oplus }$) and radii akin to those of giant planets ($>4$ R${}_{\oplus }$), their large envelopes may have been accreted beyond the water snow line and many appear to be susceptible to catastrophic mass loss. Both the presence of water and the importance of mass loss can be explored using transmission spectroscopy. Here, we present new HST WFC3 spectroscopy and updated Kepler transit depth measurements for the super-puff Kepler-79d. We do not detect any molecular absorption features in the $1.1-1.7$ $\mu$m WFC3 bandpass and the combination of Kepler and WFC3 data are consistent with a flat line model, indicating the presence of aerosols in the atmosphere. We compare the shape of Kepler-79d's transmission spectrum to predictions from a microphysical haze model that incorporates an outward particle flux due to ongoing mass loss. We find that photochemical hazes offer an attractive explanation for the observed properties of super-puffs like Kepler-79d, as they simultaneously render the near-infrared spectrum featureless and reduce the inferred envelope mass loss rate by moving the measured radius (optical depth unity surface during transit) to lower pressures. We revisit the broader question of mass loss rates for super-puffs and find that the age estimates and mass loss rates for the majority of super-puffs can be reconciled if hazes move the photosphere from the typically assumed pressure of $\sim 10$ mbar to $\sim 10\mu$bar.

arXiv commentAwaiting publication in AJ. Small updates in Table 6 and Fig 11. Table 3 and 6 will be provided in MRT format upon publication

References in corpus (101)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• batman: BAsic Transit Model cAlculatioN in Python
• A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
• Models of Stars, Brown Dwarfs and Exoplanets
• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)
• The evaporation valley in the Kepler planets
• Rotation Periods of 34,030 Kepler Main-Sequence Stars: The Full Autocorrelation Sample
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a Proxy for Composition
• The effect of red noise on planetary transit detection
• Infrared Transmission Spectroscopy of the Exoplanets HD209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope
• The California Kepler Survey VII. Precise Planet Radii Leveraging Gaia DR2 Reveal the Stellar Mass Dependence of the Planet Radius Gap
• The Role of Core Mass in Controlling Evaporation: the Kepler Radius Distribution and the Kepler-36 Density Dichotomy
• Disequilibrium Carbon, Oxygen, and Nitrogen Chemistry in the Atmospheres of HD 189733b and HD 209458b
• The Minimum-Mass Extrasolar Nebula: In-Situ Formation of Close-In Super-Earths
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• The Statistics of Albedo and Heat Recirculation on Hot Exoplanets
• 3D mixing in hot Jupiter atmospheres. I. application to the day/night cold trap in HD 209458b
• The Flat Transmission Spectrum of the Super-Earth GJ1214b from Wide Field Camera 3 on the Hubble Space Telescope
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b
• A population study of gaseous exoplanets
• The California-Kepler Survey. I. High Resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets
• A Gaussian process framework for modelling instrumental systematics: application to transmission spectroscopy
• Water Vapor and Clouds on the Habitable-Zone Sub-Neptune Exoplanet K2-18b
• Breeding Super-Earths and Birthing Super-Puffs in Transitional Disks
• Make Super-Earths, Not Jupiters: Accreting Nebular Gas onto Solid Cores at 0.1 AU and Beyond
• Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parameters
• Thermal Emission and Albedo Spectra of Super Earths with Flat Transmission Spectra
• A Sub-Neptune Exoplanet with a Low-Metallicity Methane-Depleted Atmosphere and Mie-Scattering Clouds
• LDTk: Limb Darkening Toolkit
• Atmospheres of low-mass planets: the "boil-off"
• Evolutionary Analysis of Gaseous Sub-Neptune-Mass Planets with MESA
• Detection of H2O and evidence for TiO/VO in an ultra hot exoplanet atmosphere
• A resonant chain of four transiting, sub-Neptune planets
• Kepler Planet Masses and Eccentricities from TTV Analysis
• In-situ Accretion of Hydrogen-Rich Atmospheres on Short-Period Super-Earths: Implications for the Kepler-11 Planets
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• HST hot Jupiter Transmission Spectral Survey: A detection of Na and strong optical absorption in HAT-P-1b
• Atmospheric Circulation of Hot Jupiters: Dayside-Nightside Temperature Differences
• Very Low-Density Planets around Kepler-51 Revealed with Transit Timing Variations and an Anomaly Similar to a Planet-Planet Eclipse Event
• Atmospheric Heat Redistribution on Hot Jupiters
• Simulating the escaping atmospheres of hot gas planets in the solar neighborhood
• The Complete transmission spectrum of WASP-39b with a precise water constraint
• The Oblique Orbit of the Super-Neptune HAT-P-11b
• The Formation of Super-Earths and Mini-Neptunes with Giant Impacts
• An optical transmission spectrum for the ultra-hot Jupiter WASP-121b measured with the Hubble Space Telescope
• A Grid of 3D Stellar Atmosphere Models of Solar Metallicity: I. General Properties, Granulation and Atmospheric Expansion
• Detection of He I $\lambda 10830$ Å absorption on HD 189733 b with CARMENES high-resolution transmission spectroscopy
• The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars
• Secure TTV Mass Measurements: Ten Kepler Exoplanets between 3 and 8 Earth Masses with Diverse Densities and Incident Fluxes
• Energy-limited escape revised
• Trends in Atmospheric Properties of Neptune-Size Exoplanets
• Connecting Giant Planet Atmosphere and Interior Modeling: Constraints on Atmospheric Metal Enrichment
• Haze Production in the Atmospheres of super-Earths and mini-Neptunes: Insights from the Lab
• The mass of the Mars-sized exoplanet Kepler-138 b from transit timing
• A new approach to analysing HST spatial scans: the transmission spectrum of HD 209458 b
• Forward modelling and retrievals with PLATON, a fast open source tool
• 3D modeling of GJ1214b's atmosphere: vertical mixing driven by an anti-Hadley circulation
• Theoretical transmission spectra of exoplanet atmospheres with hydrocarbon haze: Effect of creation, growth, and settling of haze particles. I. Model description and first results
• The Featureless Transmission Spectra of Two Super-Puff Planets
• Spectra as Windows into Exoplanet Atmospheres
• Transit Timing Variation of Near-Resonance Planetary Pairs. II. Confirmation of 30 planets in 15 Multiple Planet Systems
• Aeronomical constraints to the minimum mass and maximum radius of hot low-mass planets
• KOI-152's Low Density Planets
• Water, High-Altitude Condensates, and Possible Methane Depletion in the Atmosphere of the Warm Super-Neptune WASP-107b
• PLATON II: New Capabilities And A Comprehensive Retrieval on HD 189733b Transit and Eclipse Data
• Sedimentation Efficiency of Condensation Clouds in Substellar Atmospheres
• Global-mean Vertical Tracer Mixing in Planetary Atmospheres I: Theory and Fast-rotating Planets
• A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope's Wide Field Camera 3 Near-IR Detector and Applications to Transiting Exoplanets and Brown Dwarfs
• Detection of Helium in the Atmosphere of the Exo-Neptune HAT-P-11b
• Statistical Characterization of Hot Jupiter Atmospheres using Spitzer's Secondary Eclipses
• The Emergent 1.1-1.7 Micron Spectrum of the Exoplanet CoRoT-2b as Measured Using the Hubble Space Telescope
• Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System
• An emission spectrum for WASP-121b measured across the 0.8-1.1 micron wavelength range using the Hubble Space Telescope
• Tidally-Induced Radius Inflation of Sub-Neptunes
• Photochemical Haze Formation in the Atmospheres of super-Earths and mini-Neptunes
• Dusty outflows in planetary atmospheres: Understanding "super-puffs" and transmission spectra of sub-Neptunes
• Diffuser-Assisted Infrared Transit Photometry for Four Dynamically Interacting \textit{Kepler} Systems
• The Compositional Diversity of Low-Mass Exoplanets
• Granulation properties of giants, dwarfs, and white dwarfs from the CIFIST 3D model atmosphere grid
• Global-mean Vertical Tracer Mixing in Planetary Atmospheres II: Tidally Locked Planets
• An Independent Planet Search In The Kepler Dataset. II. An extremely low-density super-Earth mass planet around Kepler-87
• Laboratory Simulations of Haze Formation in the Atmospheres of super-Earths and mini-Neptunes: Particle Color and Size Distribution
• Aggregate Hazes in Exoplanet Atmospheres
• An Overabundance of Low-density Neptune-like Planets
• The Effect of Conjunctions on the Transit Timing Variations of Exoplanets
• Tidal Inflation Reconciles Low-Density Sub-Saturns with Core Accretion
• Exploring Whether Super-Puffs Can Be Explained as Ringed Exoplanets
• A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
• Hubble PanCET: An isothermal day-side atmosphere for the bloated gas-giant HAT-P-32Ab
• Evaporation of Low-Mass Planet Atmospheres: Multidimensional Hydrodynamics with Consistent Thermochemistry
• Optical to near-infrared transmission spectrum of the warm sub-Saturn HAT-P-12b
• Ohmic Dissipation in Mini-Neptunes
• Modeling the Ly$\alpha$ transit absorption of the hot Jupiter HD 189733b

Cited by in corpus (21)

• Aerosols in Exoplanet Atmospheres
• How to identify exoplanet surfaces using atmospheric trace species in hydrogen-dominated atmospheres
• Metastable Helium Absorptions with 3D Hydrodynamics and Self-Consistent Photochemistry II: WASP-107b, Stellar Wind, Radiation Pressure, and Shear Instability
• The First Near-Infrared Transmission Spectrum of HIP 41378 f, a Low-Mass Temperate Jovian World in a Multi-Planet System
• Cleaning our Hazy Lens: Exploring Trends in Transmission Spectra of Warm Exoplanets
• HD 191939 revisited: New and refined planet mass determinations, and a new planet in the habitable zone
• Radial Gradients in Dust-to-Gas Ratio Lead to Preferred Region for Giant Planet Formation
• Spatially Resolved Modeling of Optical Albedos for a Sample of Six Hot Jupiters
• Sculpting the sub-Saturn Occurrence Rate via Atmospheric Mass Loss
• Following up the Kepler field: Masses of Targets for transit timing and atmospheric characterization
• A Framework for Characterizing Transmission Spectra of Exoplanets with Circumplanetary Rings
• Dynamics and Clouds in Planetary Atmospheres from Telescopic Observations
• TESS Observations of Kepler systems with Transit Timing Variations
• Oblique rings from migrating exomoons: A possible origin for long-period exoplanets with enlarged radii
• Transit Depth Variations Reveal TOI-216 b to be a Super-Puff
• Strong NUV Refractory Absorption and Dissociated Water in the Hubble Transmission Spectrum of the Ultra Hot Jupiter KELT-20 b
• The Hubble PanCET Program: A Featureless Transmission Spectrum for WASP-29b and Evidence of Enhanced Atmospheric Metallicity on WASP-80b
• TOI-3757 b: A low density gas giant orbiting a solar-metallicity M dwarf
• Grain Growth in Escaping Atmospheres: Implications for the Radius Inflation of Super-Puffs
• Refining the Masses and Radii of the Star Kepler-33 and its Five Transiting Planets
• A Multi-Planet System's Sole Super-Puff: Exploring Allowable Physical Parameters for the Cold Super-Puff HIP 41378 f