K2-98 b: A 32-M${}_{\oplus }$ Neptune-sized planet in a 10-day orbit transiting an F8 star

Abstract

We report the discovery of K2-98 b (EPIC 211391664 b), a transiting Neptune-sized planet monitored by the K2 mission during its campaign 5. We combine the K2 time-series data with ground-based photometric and spectroscopic follow-up observations to confirm the planetary nature of the object and derive its mass, radius, and orbital parameters. K2-98 b is a warm Neptune-like planet in a 10-day orbit around a V=12.2~mag F-type star with $M_{\star }$=$1.074\pm 0.042$, $R_{\star }$=$1.311_{-0.048}^{+0.083}$, and age of $5.2_{-1.0}^{+1.2}$~Gyr. We derive a planetary mass and radius of $M_{\mathrm{p}}$=$32.2\pm 8.1$ and $R_{\mathrm{p}}$=$4.3_{-0.2}^{+0.3}$. K2-98 b joins the relatively small group of Neptune-sized planets whose both mass and radius have been derived with a precision better than 25 %. We estimate that the planet will be engulfed by its host star in $\sim$3~Gyr, due to the evolution of the latter towards the red giant branch.

11 pages, 4 figures, Accepted for publication in AJ

References in corpus (15)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The K2 Mission: Characterization and Early results
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• Determining stellar macroturbulence using asteroseismic rotational velocities from Kepler
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• 197 Candidates and 104 Validated Planets in K2's First Five Fields
• Formation of close in Super-Earths \& Mini-Neptunes: Required Disk Masses \& Their Implications
• The effect of stellar limb darkening values on the accuracy of the planet radii derived from photometric transit observations
• Occurrence and core-envelope structure of 1--4x Earth-size planets around Sun-like stars
• Transiting exoplanets from the CoRoT space mission XIV. CoRoT-11b: a transiting massive "hot-Jupiter" in a prograde orbit around a rapidly rotating F-type star
• From Hot Jupiters to Super-Earths via Roche Lobe Overflow
• Evolution of angular-momentum-losing exoplanetary systems : Revisiting Darwin stability
• Kepler423b: a half-Jupiter mass planet transiting a very old solar-like star
• A study of the performance of the transit detection tool DST in space-based surveys. Application of the CoRoT pipeline to Kepler data
• Wavelet-based filter methods to detect small transiting planets in stellar light curves

Cited by in corpus (10)

• The transiting multi-planet system HD3167: a 5.7 MEarth Super-Earth and a 8.3 MEarth mini-Neptune
• EPIC 219388192 b - an inhabitant of the brown dwarf desert in the Ruprecht 147 open cluster
• Tidal Inflation Reconciles Low-Density Sub-Saturns with Core Accretion
• K2-60b and epic 216468514b. A sub-jovian and a jovian planet from the k2 mission
• TOI-1268b: the youngest, hot, Saturn-mass transiting exoplanet
• The K2 & TESS Synergy II: Revisiting 26 systems in the TESS Primary Mission
• VaTEST I: Validation of Sub-Saturn Exoplanet TOI-181b in Narrow Orbit from its Host Star
• K2-280b -- a low density warm sub-Saturn around a mildly evolved star
• PLATOSpec: a precise spectrograph in support of space missions
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution