Monitoring of the D Doublet of Neutral Sodium during Transits of Two "Evaporating" Planets

Abstract

Spectroscopic transit detection of constituents in winds from "evaporating" planets on close-in transiting orbits could provide desperately needed information on the composition, formation, and orbital evolution of such objects. We obtained high-resolution optical spectra of the host stars during a single transit of Kepler-1520b and two transits of K2-22b to search for transient, Doppler-shifted absorption in the D lines of neutral sodium. Sodium should be released in the same silicate vapor wind that lofts the dust responsible for the periodic "dips" in the light curve. We do not detect any absorption lines with depths >30% at the predicted Doppler-shifted wavelengths during any of the transits. Detection sensitivity is limited by instrumental resolution that dilutes the saturated lines, and blurring of the lines by Doppler acceleration due to the short orbital period of the planet and long integration times for these faint stars. A model of neutral sodium production, escape, and ionization by UV radiation suggests that clouds of partially ionized sodium that are comparable in size to the host stars and optically thick in the D lines could accompany the planets. We consider the prospects for future detections brought about by the TESS all-sky survey of brighter stars and the advent of high-resolution spectrographs on Extremely Large Telescopes.

arXiv commentAccepted to MNRAS, 24 February 2019

References in corpus (48)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Transiting Exoplanet Survey Satellite
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• Local Kinematics and the Local Standard of Rest
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• The Dartmouth Stellar Evolution Database
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• Detection of an Extrasolar Planet Atmosphere
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Most 1.6 Earth-Radius Planets are not Rocky
• The TESS Input Catalog and Candidate Target List
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• The Mass-Radius Relation for 65 Exoplanets Smaller than 4 Earth Radii
• BANYAN. XI. The BANYAN $\Sigma$ multivariate Bayesian algorithm to identify members of young associations within 150 pc
• Galactic Reddening in 3D from Stellar Photometry - An Improved Map
• The Minimum-Mass Extrasolar Nebula: In-Situ Formation of Close-In Super-Earths
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• The MUSCLES Treasury Survey I: Motivation and Overview
• Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE passbands
• How to Constrain Your M dwarf II: the mass-luminosity-metallicity relation from 0.075 to 0.70$M_{\odot }$
• Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2
• Solar System Abundances of the Elements
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• A Study of the Shortest-Period Planets Found With Kepler
• The MUSCLES Treasury Survey III: X-ray to Infrared Spectra of 11 M and K Stars Hosting Planets
• Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548
• Radiative recombination data for modelling dynamic finite-density plasmas
• Chemistry of Silicate Atmospheres of Evaporating Super-Earths
• A High-Precision NIR Survey for RV Variable Low-Mass Stars
• The K2-ESPRINT Project. I. Discovery of the Disintegrating Rocky Planet K2-22b with a Cometary Head and Leading Tail
• KOI-2700b - A Planet Candidate With Dusty Effluents on a 22-Hour Orbit
• Atmosphere-interior exchange on hot rocky exoplanets
• Catastrophic Evaporation of Rocky Planets
• Thermally-driven atmospheric escape: Transition from hydrodynamic to Jeans escape
• GTC OSIRIS transiting exoplanet atmospheric survey: detection of sodium in XO-2b from differential long-slit spectroscopy
• K2 Rotation Periods for low-mass Hyads and the Implications for Gyrochronology
• Exoplanets around Low-mass Stars Unveiled by K2
• Search for an exosphere in sodium and calcium in the transmission spectrum of exoplanet 55 Cancri e
• Multiwavelength Observations of the Candidate Disintegrating sub-Mercury KIC 12557548b
• Evidence for the disintegration of KIC 12557548 b
• Atmospheres of Hot Super-Earths
• Investigating the Rotational Phase of Stellar Flares on M dwarfs Using K2 Short Cadence Data
• Direct evidence for an evolving dust cloud from the exoplanet KIC 12557548 b
• Detection of sodium absorption in WASP-17b with Magellan
• Analysis and interpretation of 15 quarters of Kepler data of the disintegrating planet KIC 12557548 b
• Defocussed Transmission Spectroscopy: A potential detection of sodium in the atmosphere of WASP-12b
• A Large Ground-Based Observing Campaign of the Disintegrating Planet K2-22b
• Back to "Normal" for the Disintegrating Planet Candidate KIC 12557548 b

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