The discovery of three hot Jupiters, NGTS-23b, 24b and 25b, and updated parameters for HATS-54b from the Next Generation Transit Survey

Abstract

We report the discovery of three new hot Jupiters with the Next Generation Transit Survey (NGTS) as well as updated parameters for HATS-54b, which was independently discovered by NGTS. NGTS-23b, NGTS-24b and NGTS-25b have orbital periods of 4.076, 3.468, and 2.823 days and orbit G-, F- and K-type stars, respectively. NGTS-24 and HATS-54 appear close to transitioning off the main-sequence (if they are not already doing so), and therefore are interesting targets given the observed lack of Hot Jupiters around sub-giant stars. By considering the host star luminosities and the planets' small orbital separations (0.037 - 0.050 au), we find that all four hot Jupiters are above the minimum irradiance threshold for inflation mechanisms to be effective. NGTS-23b has a mass of 0.61 $M_J$ and radius of 1.27 $R_J$ and is likely inflated. With a radius of 1.21 $R_J$ and mass of 0.52 $M_J$, NGTS-24b has a radius larger than expected from non-inflated models but its radius is smaller than the predicted radius from current Bayesian inflationary models. Finally, NGTS-25b is intermediate between the inflated and non-inflated cases, having a mass of 0.64 $M_J$ and a radius of 1.02 $R_J$. The physical processes driving radius inflation remain poorly understood, and by building the sample of hot Jupiters we can aim to identify the additional controlling parameters, such as metallicity and stellar age.

arXiv comment17 pages, 8 figures. Accepted for publication in MNRAS

References in corpus (71)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• emcee: The MCMC Hammer
• The chemical composition of the Sun
• 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
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• MESA Isochrones and Stellar Tracks (MIST). I: Solar-Scaled Models
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• dynesty: A Dynamic Nested Sampling Package for Estimating Bayesian Posteriors and Evidences
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• Local Kinematics and the Local Standard of Rest
• The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms
• The NextGen Model Atmosphere grid for $3000\le \Teff \le 10000\K$
• Fast and scalable Gaussian process modeling with applications to astronomical time series
• The Revised TESS Input Catalog and Candidate Target List
• Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits
• A box-fitting algorithm in the search for periodic transits
• Models of Stars, Brown Dwarfs and Exoplanets
• Efficient, uninformative sampling of limb darkening coefficients for two-parameter laws
• No planet for HD 166435
• Gaia Data Release 2: Catalogue validation
• Correcting systematic effects in a large set of photometric lightcurves
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Tidal dissipation in stars and giant planets
• The Mass-Metallicity Relation for Giant Planets
• Evolution of "51Peg b-like" Planets
• Structure and evolution of super-Earth to super-Jupiter exoplanets: I. heavy element enrichment in the interior
• Modern stellar spectroscopy caveats
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• The Orbital Evolution of Gas Giant Planets around Giant Stars
• On the Radii of Extrasolar Giant Planets
• Inflating Hot Jupiters With Ohmic Dissipation
• The Next Generation Transit Survey (NGTS)
• The Heavy Element Masses of Extrasolar Giant Planets, Revealed
• Lack of Inflated Radii for Kepler Giant Planet Candidates Receiving Modest Stellar Irradiation
• CERES: A Set of Automated Routines for Echelle Spectra
• A fast hybrid algorithm for exoplanetary transit searches
• On the Anomalous Radii of the Transiting Extrasolar Planets
• Occurrence Rates of Planets orbiting FGK Stars: Combining Kepler DR25, Gaia DR2 and Bayesian Inference
• Heat transport in giant (exo)planets: a new perspective
• Bayesian Analysis of Hot Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?
• Atomic data for the Gaia-ESO Survey
• The Apparently Decaying Orbit of WASP-12
• The Orbit of WASP-12b is Decaying
• Calibration of Equilibrium Tide Theory for Extrasolar Planet Systems
• ELLC - a fast, flexible light curve model for detached eclipsing binary stars and transiting exoplanets
• Departure from the constant-period ephemeris for the transiting exoplanet WASP-12 b
• Ohmic Dissipation in the Atmospheres of Hot Jupiters
• WASP-42 b and WASP-49 b: two new transiting sub-Jupiters
• Inflating and Deflating Hot Jupiters: Coupled Tidal and Thermal Evolution of Known Transiting Planets
• ARIADNE: Measuring accurate and precise stellar parameters through SED fitting
• Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars
• Two new HATNet hot Jupiters around A stars, and the first glimpse at the occurrence rate of hot Jupiters from TESS
• WASP-44b, WASP-45b and WASP-46b: three short-period, transiting extrasolar planets
• The continuing search for evidence of tidal orbital decay of hot Jupiters
• NGTS-4b: A sub-Neptune Transiting in the Desert
• Extended Heat Deposition in Hot Jupiters: Application to Ohmic Heating
• Investigating hot-Jupiter inflated radii with hierarchical Bayesian modelling
• HAT-P-65b and HAT-P-66b: Two Transiting Inflated Hot Jupiters and Observational Evidence for the Re-Inflation of Close-In Giant Planets
• NGTS clusters survey. I. Rotation in the young benchmark open cluster Blanco 1
• The fate of close-in planets: tidal or magnetic migration?
• Slow Cooling and Fast Reinflation for Hot Jupiters
• Re-inflation of warm and hot Jupiters
• Estimating the masses of extra-solar planets
• HATS-54b-HATS-58Ab: five new transiting hot Jupiters including one with a possible temperate companion
• Tidal heating and stellar irradiation of Hot Jupiters
• NGTS-14Ab: a Neptune-sized transiting planet in the desert
• NGTS-8b and NGTS-9b: two non-inflated hot-Jupiters
• NGTS 15b, 16b, 17b and 18b: four hot Jupiters from the Next Generation Transit Survey

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