Transiting exoplanets from the CoRoT space mission: XXVI. CoRoT-24: A transiting multi-planet system

Abstract

We present the discovery of a candidate multiply-transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76d are detected in the CoRoT light curve, around a main sequence K1V star of r=15.1. If the features are due to transiting planets around the same star, these would correspond to objects of 3.7$\pm$0.4 and 5.0$\pm$0.5 R_earth respectively. Several radial velocities serve to provide an upper limit of 5.7 M_earth for the 5.11~d signal, and to tentatively measure a mass of 28${}_{-11}^{+11}$ M_earth for the object transiting with a 11.76~d period. These measurements imply low density objects, with a significant gaseous envelope. The detailed analysis of the photometric and spectroscopic data serve to estimate the probability that the observations are caused by transiting Neptune-sized planets as $>$26$\times$ higher than a blend scenario involving only one transiting planet, and $>$900$\times$ higher than a scenario involving two blends and no planets. The radial velocities show a long term modulation that might be attributed to a 1.5 M_jup planet orbiting at 1.8~A.U. from the host, but more data are required to determine the precise orbital parameters of this companion.

arXiv comment13 pages, 13 figures, accepted to A&A, minor typos corrected

References in corpus (37)

• Correcting for the Effects of Interstellar Extinction
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data
• A box-fitting algorithm in the search for periodic transits
• The CoRoT satellite in flight : description and performance
• A Closely-Packed System of Low-Mass, Low-Density Planets Transiting Kepler-11
• Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius
• KEPLER's First Rocky Planet: Kepler-10b
• Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems
• Kepler Eclipsing Binary Stars. II. 2165 Eclipsing Binaries in the Second Data Release
• Eclipsing binaries in open clusters. II. V453 Cyg in NGC 6871
• The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
• Thermohaline instability and rotation-induced mixing. III - Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars at various metallicities
• A Super-Earth Transiting a Naked-Eye Star
• Stellar Limb-Darkening Coefficients for CoRot and Kepler
• Transiting exoplanets from the CoRoT space mission II. CoRoT-Exo-2b: A transiting planet around an active G star
• Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system
• Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models
• Validation of Kepler's Multiple Planet Candidates. II: Refined Statistical Framework and Descriptions of Systems of Special Interest
• Planetary Candidates Observed by Kepler IV: Planet Sample From Q1-Q8 (22 Months)
• A sub-Mercury-sized exoplanet
• Detection of a transit of the super-Earth 55 Cnc e with Warm Spitzer
• Kepler 18-b, c, and d: A System Of Three Planets Confirmed by Transit Timing Variations, Lightcurve Validation, Spitzer Photometry and Radial Velocity Measurements
• Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability
• A First Comparison of Kepler Planet Candidates in Single and Multiple Systems
• Improved stellar parameters of CoRoT-7
• On the Mass of CoRoT-7b
• Eclipsing binaries in open clusters. III. V621 Per in chi Persei
• The Kepler-19 System: A Transiting 2.2 R_Earth Planet and a Second Planet Detected via Transit Timing Variations
• Testing blend scenarios for extrasolar transiting planet candidates. I. -- OGLE-TR-33: a false positive
• Kepler-10c, a 2.2-Earth radius transiting planet in a multiple system
• Ground-based photometry of space-based transit detections: Photometric follow-up of the CoRoT mission
• Seismic and dynamical solar models i-the impact of the solar rotation history on neutrinos and seismic indicators
• A Photometric Diagnostic to Aid in the Identification of Transiting Extra-Solar Planets
• High angular resolution imaging and infrared spectroscopy of CoRoT candidates
• Radial velocity follow-up of CoRoT transiting exoplanets
• Periodic variable stars in CoRoT field LRa02 observed with BEST II

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• A New Model of Roche-lobe Overflow for Short-Period Gaseous Planets and Binary Stars
• Planets, candidates, and binaries from the CoRoT/Exoplanet programme: the CoRoT transit catalogue
• ExoClock Project: An open platform for monitoring the ephemerides of Ariel targets with contributions from the public
• Original Research By Young Twinkle Students (ORBYTS): Ephemeris Refinement of Transiting Exoplanets
• Ephemeris refinement of 21 Hot Jupiter exoplanets with high timing uncertainties
• Resonant sub-Neptunes are puffier
• Stellar obliquities and magnetic activities of Planet-Hosting Stars and Eclipsing Binaries based on Transit Chord Correlation
• CoRoT: The First Space-Based Transit Survey to Explore the Close-in Planet Population
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution