Polarization of hot Jupiter systems: a likely detection of stellar activity and a possible detection of planetary polarization

Abstract

We present high-precision linear polarization observations of four bright hot Jupiter systems ($\tau$ Boo, HD 179949, HD 189733 and 51 Peg) and use the data to search for polarized reflected light from the planets. The data for 51 Peg are consistent with a reflected light polarization signal at about the level expected with 2.8$\sigma$ significance and a false alarm probability of 1.9 per cent. More data will be needed to confirm a detection of reflected light in this system. HD 189733 shows highly variable polarization that appears to be most likely the result of magnetic activity of the host star. This masks any polarization due to reflected light, but a polarization signal at the expected level of $\sim$20 ppm cannot be ruled out. $\tau$ Boo and HD 179949 show no evidence for polarization due to reflected light. The results are consistent with the idea that many hot Jupiters have low geometric albedos. Conclusive detection of polarized reflected light from hot Jupiters is likely to require further improvements in instrument sensitivity.

arXiv comment16 pages, 8 figures, accepted by MNRAS

References in corpus (83)

• Gaia Data Release 2. Summary of the contents and survey properties
• Validation of the new Hipparcos reduction
• A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
• Catalog of Nearby Exoplanets
• A map of the day-night contrast of the extrasolar planet HD 189733b
• Improved parameters for extrasolar transiting planets
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I
• Sodium Absorption From the Exoplanetary Atmosphere of HD189733b Detected in the Optical Transmission Spectrum
• The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations
• The signature of orbital motion from the dayside of the planet tau Bootis b
• Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 microns
• Photometric Light Curves and Polarization of Close-in Extrasolar Giant Planets
• Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b: 1. the Transit
• The On/Off Nature of Star-Planet Interactions
• Hot Jupiters and Hot Spots: The Short- and Long-term Chromospheric Activity on Stars with Giant Planets
• Temporal variations in the evaporating atmosphere of the exoplanet HD 189733b
• Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b
• Transmission spectral properties of clouds for hot Jupiter exoplanets
• Searching for Star-Planet interactions within the magnetosphere of HD 189733
• The Rossiter-McLaughlin effect of CoRoT-3b & HD189733b
• An Upper Limit on the Reflected Light from the Planet Orbiting the Star tau Bootis
• Magnetic cycles of the planet-hosting star tauBootis
• The Transit Light Curve Project. V. System Parameters and Stellar Rotation Period of HD 189733
• A Two-Dimensional Infrared Map of the Extrasolar Planet HD 189733b
• The Deep Blue Color of HD189733b: Albedo Measurements with Hubble Space Telescope/Space Telescope Imaging Spectrograph at Visible Wavelengths
• Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b
• Spatially resolved eastward winds and rotation of HD 189733b
• Weighing The Non-Transiting Hot Jupiter Tau BOO b
• The high albedo of the hot Jupiter Kepler-7b
• Hot Nights on Extrasolar Planets: Mid-IR Phase Variations of Hot Jupiters
• A comprehensive study of Kepler phase curves and secondary eclipses -- temperatures and albedos of confirmed Kepler giant planets
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• Near-IR Direct Detection of Water Vapor in Tau Boo b
• Magnetic field, differential rotation and activity of the hot-Jupiter hosting star HD 179949
• The Rotation Period of the Planet-Hosting Star HD 189733
• MOST detects variability on tau Bootis possibly induced by its planetary companion
• Polarized reflected light from the exoplanet HD189733b: First multicolor observations and confirmation of detection
• First detection of polarized scattered light from an exoplanetary atmosphere
• Water vapor in the spectrum of the extrasolar planet HD 189733b: 2. The eclipse
• Evidence for a spectroscopic direct detection of reflected light from 51 Peg b
• Multiple water band detections in the CARMENES near-infrared transmission spectrum of HD 189733 b
• Detection of visible light from the darkest world
• The Evolving Magnetic Topology of $\tau$ Boötis
• Wind of Change: retrieving exoplanet atmospheric winds from high-resolution spectroscopy
• Investigating hot-Jupiter inflated radii with hierarchical Bayesian modelling
• A posteriori detection of the planetary transit of HD189733b in the Hipparcos photometry
• Systematic Phase Curve Study of Known Transiting Systems from Year 1 of the TESS Mission
• A high-sensitivity polarimeter using a ferro-electric liquid crystal modulator
• A grid of polarization models for Rayleigh scattering planetary atmospheres
• The linear polarization of nearby bright stars measured at the parts per million level
• Modelling the Spectra of Planets, Brown Dwarfs and Stars using VSTAR
• Non-Detection of Polarized, Scattered Light from the HD 189733b Hot Jupiter
• The relation between stellar magnetic field geometry and chromospheric activity cycles II: The rapid 120 day magnetic cycle of Tau Bootis
• A Ground-Based Albedo Upper Limit for HD 189733b from Polarimetry
• Planetpol polarimetry of the exoplanet systems 55 Cnc and tau Boo
• The Dawes Review 3: The Atmospheres of Extrasolar Planets and Brown Dwarfs
• Polarization measurements of hot dust stars and the local interstellar medium
• MOVES I. The evolving magnetic field of the planet-hosting star HD189733
• The linear polarisation of southern bright stars measured at the parts-per-million level
• Tau Boo b: Hunting for reflected starlight
• Polarization due to rotational distortion in the bright star Regulus
• The polarisation of HD 189733
• A High Precision, Optical Polarimeter to Measure Inclinations of High Mass X-Ray Binaries
• The intrinsic and interstellar broadband linear polarization of nearby FGK dwarfs
• On the chromospheric activity of stars with planets
• HIPPI-2: A Versatile High Precision Polarimeter
• Simultaneous Linear and Circular Optical Polarimetry of Asteroid (4) Vesta
• Polarized Radiative Transfer in Planetary Atmospheres and the Polarization of Exoplanets
• Searching for reflected light from $\tau$ Bootis b with high-resolution ground-based spectroscopy: Approaching the $10^{-5}$ contrast barrier
• A high precision polarimeter for small telescopes
• The wavelength dependence of interstellar polarization in the Local Hot Bubble
• 51 Pegasi - a planet-bearing Maunder minimum candidate
• Polarization in exoplanetary systems caused by transits, grazing transits, and starspots
• A Multiple Scattering Polarized Radiative Transfer Model: Application to HD 189733b
• The polarization of the planet-hosting WASP-18 system
• The Rotationally Modulated Polarization of $\xi$ Boo A
• The rotation of alpha Oph investigated using polarimetry
• Polarimetric and radiative transfer modelling of HD 172555
• WASP-104b is Darker than Charcoal
• Phase-locked polarization by photospheric reflection in the semidetached eclipsing binary ${\mu }^1$ Sco
• Polarization measurements of the polluted white dwarf G29-38
• Polarization of stars with debris disks: comparing observations with models
• The polarization of the binary system Spica, and the reflection of light from stars

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