NGTS-12b: A sub-Saturn mass transiting exoplanet in a 7.53 day orbit

Abstract

We report the discovery of the transiting exoplanet NGTS-12b by the Next Generation Transit Survey (NGTS). The host star, NGTS-12, is a V=12.38 mag star with an effective temperature of T${}_{\mathrm{eff}}$=$5690\pm 130$ K. NGTS-12b orbits with a period of $P=7.53$d, making it the longest period planet discovered to date by the main NGTS survey. We verify the NGTS transit signal with data extracted from the TESS full-frame images, and combining the photometry with radial velocity measurements from HARPS and FEROS we determine NGTS-12b to have a mass of $0.208\pm 0.022$ M${}_J$ and a radius of $1.048\pm 0.032$ R${}_J$. NGTS-12b sits on the edge of the Neptunian desert when we take the stellar properties into account, highlighting the importance of considering both the planet and star when studying the desert. The long period of NGTS-12b combined with its low density of just $0.223\pm 0.029$ g cm${}^{-3}$ make it an attractive target for atmospheric characterization through transmission spectroscopy with a Transmission Spectroscopy Metric of 89.4.

arXiv commentAccepted for publication in MNRAS, 11 pages

References in corpus (47)

• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Transiting Exoplanet Survey Satellite
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• MESA Isochrones and Stellar Tracks (MIST) 0: Methods for the construction of stellar isochrones
• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• The WASP Project and the SuperWASP Cameras
• The Revised TESS Input Catalog and Candidate Target List
• A box-fitting algorithm in the search for periodic transits
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization
• Wide-field millimagnitude photometry with HAT: A Tool for Extra-solar Planet Detection
• Correcting systematic effects in a large set of photometric lightcurves
• The Kilodegree Extremely Little Telescope (KELT): A Small Robotic Telescope for Large-Area Synoptic Surveys
• Dearth of short-period Neptunian exoplanets - a desert in period-mass and period-radius planes
• Structure and evolution of super-Earth to super-Jupiter exoplanets: I. heavy element enrichment in the interior
• STARRY: Analytic Occultation Light Curves
• Parametrizing the exoplanet eccentricity distribution with the Beta distribution
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• The Next Generation Transit Survey (NGTS)
• Foretellings of Ragnarök: World-engulfing Asymptotic Giants and the Inheritance of White Dwarfs
• CERES: A Set of Automated Routines for Echelle Spectra
• Two new "very hot Jupiters" among the OGLE transiting candidates
• Hot Jupiters and Cool Stars
• Distant future of the Sun and Earth revisited
• The Great Escape: How Exoplanets and Smaller Bodies Desert Dying Stars
• Long Term Evolution of Close Planets Including the Effects of Secular Interactions
• Analytic Planetary Transit Light Curves and Derivatives for Stars with Polynomial Limb Darkening
• A method for the direct determination of the surface gravities of transiting extrasolar planets
• The Transiting Exoplanet Community Early Release Science Program for JWST
• The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters and a planet in the transition region between ice giants and gas giants
• Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program
• NGTS-4b: A sub-Neptune Transiting in the Desert
• Cluster Difference Imaging Photometric Survey. I. Light Curves of Stars in Open Clusters from TESS Sectors 6 & 7
• Evolution of Planetary Orbits with Stellar Mass Loss and Tidal Dissipation
• Bayesian priors for the eccentricity of transiting planets
• Tidal Inflation Reconciles Low-Density Sub-Saturns with Core Accretion
• DONUTS: A science frame autoguiding algorithm with sub-pixel precision, capable of guiding on defocused stars
• The Effect of Tides on the Population of PN from Interacting Binaries
• NGTS-11 b / TOI-1847 b: A transiting warm Saturn recovered from a TESS single-transit event
• Cold giant planets evaporated by hot white dwarfs
• The fates of Solar system analogues with one additional distant planet
• Classifying Exoplanet Candidates with Convolutional Neural Networks: Application to the Next Generation Transit Survey
• NGTS-5b: a highly inflated planet offering insights into the sub-Jovian desert
• The atmospheric parameters of FGK stars using wavelet analysis of CORALIE spectra

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