Disentangling Planets and Stellar Activity for Gliese 667C

Abstract

Gliese 667C is an M1.5V star with a multi-planet system, including planet candidates in the habitable zone (HZ). The exact number of planets in the system is unclear, because the existing radial velocity (RV) measurements are known to contain contributions from stellar magnetic activity. Following our analysis of Gliese 581 (Robertson et al. 2014), we have analyzed the effect of stellar activity on the HARPS/HARPS-TERRA RVs of GJ 667C, finding significant RV-activity correlation when using the width (FWHM) of the HARPS cross-correlation function to trace magnetic activity. When we correct for this correlation, we confirm the detections of the previously-observed planets b and c in the system, while simultaneously ascribing the RV signal near 90 days ("planet d") to an artifact of the stellar rotation. We are unable to confirm the existence of the additional RV periodicities described in Anglada-Escude et al. (2013) in our activity-corrected data.

arXiv commentAccepted for publication in the Astrophysical Journal Letters

References in corpus (19)

• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• Habitable Zones Around Main-Sequence Stars: New Estimates
• The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• The HARPS-TERRA project I. Description of the algorithms, performance and new measurements on a few remarkable stars observed by HARPS
• A dynamically-packed planetary system around GJ667C with three super-Earths in its habitable zone
• Stellar Activity Masquerading as Planets in the Habitable Zone of the M dwarf Gliese 581
• NEXXUS: A comprehensive ROSAT survey of coronal X-ray emission among nearby solar-like stars
• Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program I. Comparison of activity indices
• A planetary system around the nearby M dwarf GJ 667C with at least one super-Earth in its habitable zone
• Systemic: A Testbed For Characterizing the Detection of Extrasolar Planets. I. The Systemic Console Package
• H-alpha Activity of Old M Dwarfs: Stellar Cycles and Mean Activity Levels For 93 Low-Mass Stars in the Solar Neighborhood
• The HARPS search for southern extra-solar planets XXXV. Super-Earths around the M-dwarf neighbors Gl433 and Gl667C
• Bayesian analysis of radial velocity data of GJ667C with correlated noise: evidence for only 2 planets
• Do stellar magnetic cycles influence the measurement of precise radial velocities?
• The Na I D resonance lines in main sequence late-type stars
• A planetary system with gas giants and super-Earths around the nearby M dwarf GJ 676A. Optimizing data analysis techniques for the detection of multi-planetary systems
• MARVELS-1: A face-on double-lined binary star masquerading as a resonant planetary system; and consideration of rare false positives in radial velocity planet searches
• Dynamical evolution and spin-orbit resonances of potentially habitable exoplanets. The case of GJ 667C

Cited by in corpus (51)

• A Gaussian process framework for modelling stellar activity signals in radial velocity data
• The inner edge of the habitable zone for synchronously rotating planets around low-mass stars using general circulation models
• Rotation periods of late-type dwarf stars from time-series high-resolution spectroscopy of chromospheric indicators
• The VLT-FLAMES Tarantula Survey XXII. Multiplicity properties of the B-type stars
• A Kepler Study of Starspot Lifetimes with Respect to Light Curve Amplitude and Spectral Type
• Gaia DR3 astrometric orbit determination with Markov Chain Monte Carlo and Genetic Algorithms. Systems with stellar, substellar, and planetary mass companions
• Stellar activity mimics a habitable-zone planet around Kapteyn's star
• Habitability of planets on eccentric orbits: the limits of the mean flux approximation
• The CARMENES search for exoplanets around M dwarfs: A low-mass planet in the temperate zone of the nearby K2-18
• A Versatile Technique to Enable sub-milli-Kelvin Instrument Stability for Precise Radial Velocity Measurements: Tests with the Habitable-zone Planet Finder
• Radial Velocity Planet Detection Biases at the Stellar Rotational Period
• Miniature Exoplanet Radial Velocity Array (MINERVA) I. Design, Commissioning, and First Science Results
• An Empirically Derived Three-Dimensional Laplace Resonance in the Gliese 876 Planetary System
• Characterisation of the radial velocity signal induced by rotation in late-type dwarfs
• Modelling the photosphere of active stars for planet detection and characterization
• The Impact of Stellar Rotation on the Detectability of Habitable Planets Around M Dwarfs
• Towards Understanding Stellar Radial Velocity Jitter as a Function of Wavelength: The Sun as a Proxy
• Quantifying the Bayesian Evidence for a Planet in Radial Velocity Data
• A More Precise Mass for GJ 1214 b and the Frequency of Multi-Planet Systems Around Mid-M Dwarfs
• Stellar Activity and its Implications for Exoplanet Detection on GJ 176
• Toward Extremely Precise Radial Velocities: II. A Tool For Using Multivariate Gaussian Processes to Model Stellar Activity
• Starspot occultations in infrared transit spectroscopy: the case of WASP-52b
• An upper boundary in the mass-metallicity plane of exo-Neptunes
• The SPIRou Legacy Survey Rotation period of quiet M dwarfs from circular polarization in near-infrared spectral lines: I. The SPIRou APERO analysis
• Characterisation of stellar activity of M dwarfs. I. Long-timescale variability in a large sample and detection of new cycles
• A robust, template-free approach to precise radial velocity extraction
• No evidence for activity correlations in the radial velocities of Kapteyn's star
• The CARMENES search for exoplanets around M dwarfs, Wolf 1069 b: Earth-mass planet in the habitable zone of a nearby, very low-mass star
• The HARPS search for southern extra-solar planets. XXXIX. HD175607 b, the most metal-poor G dwarf with an orbiting sub-Neptune
• A HARPS-N mass for the elusive Kepler-37d: a case study in disentangling stellar activity and planetary signals
• Activity time series of old stars from late F to early K. IV. Limits of the correction of radial velocities using chromospheric emission
• Response to Comment on "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581"
• Relationship between Ca and H$\alpha$ chromospheric emission in F-G-K stars: indication of stellar filaments?
• Magnitude-squared coherence: A powerful tool for disentangling Doppler planet discoveries from stellar activity
• 3D magneto-hydrodynamical simulations of stellar convective noise for improved exoplanet detection. I. Case of regularly sampled radial velocity observations
• Large Interferometer For Exoplanets (LIFE). X. Detectability of currently known exoplanets and synergies with future IR/O/UV reflected-starlight imaging missions
• Variability Timescales of H$\alpha$ on Active Mid-to-Late M dwarfs
• Radial Velocities as an Exoplanet Discovery Method
• Calculations of periodicity from Hα profiles of Proxima Centauri
• The HARPS search for southern extra-solar planets XL. Searching for Neptunes around metal-poor stars
• H${}_2$ Fluorescence in M Dwarf Systems: A Stellar Origin
• Radial velocity homogeneous analysis of M dwarfs observed with HARPS I. Exoplanet detection and candidates
• Detailed stellar activity analysis and modelling of GJ 832: Reassessment of the putative habitable zone planet GJ 832c
• An Early Catalog of Planet Hosting Multiple Star Systems of Order Three and Higher
• The Solar Neighborhood LI: A Variability Survey of Nearby M Dwarfs with Planets from Months to Decades with TESS and the CTIO/SMARTS 0.9 m Telescope
• Predicting convective blueshift and radial-velocity dispersion due to granulation for FGK stars
• New Dynamical State and Habitability of the HD 45364 Planetary System
• L 363-38 b: a planet newly discovered with ESPRESSO orbiting a nearby M dwarf star
• Radial velocity homogeneous analysis of M dwarfs observed with HARPS. II. Detection limits and planetary occurrence statistics
• Activity-rotation in the dM4 star Gl 729. A possible chromospheric cycle
• Revisiting BD-06 1339b: A Likely False Positive Caused by Stellar Activity