Reassessment of the Null Result of the HST Search for Planets in 47 Tucanae

Abstract

We revisit the null result of the Hubble Space Telescope search for transiting planets in the globular cluster 47 Tucanae, in the light of improved knowledge of planet occurrence from the Kepler mission. Gilliland and co-workers expected to find 17 planets, assuming the 47 Tuc stars have close-in giant planets with the same characteristics and occurrence rate as those of the nearby stars that had been surveyed up until 1999. We update this result by assuming that 47 Tuc and Kepler stars have identical planet populations. The revised number of expected detections is $4.0_{-1.4}^{+1.7}$. When we restrict the Kepler stars to the same range of masses as the stars that were searched in 47 Tuc, the number of expected detections is reduced to $2.2_{-1.1}^{+1.6}$. Thus, the null result of the HST search is less statistically significant than it originally seemed. We cannot reject even the extreme hypothesis that 47 Tuc and Kepler stars have the same planet populations, with more than 2-3$\sigma$ significance. More sensitive searches are needed to allow comparisons between the planet populations of globular clusters and field stars.

10 pages, 4 figures, AJ accepted

References in corpus (13)

• The Dartmouth Stellar Evolution Database
• Improved parameters for extrasolar transiting planets
• False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• In Situ Formation and Dynamical Evolution of Hot Jupiter Systems
• Dynamics of Planetary Systems in Star Clusters
• An Eccentric Hot Jupiter Orbiting the Subgiant HD 185269
• Globular Cluster Abundances from High-Resolution Integrated Light Spectra, I: 47 Tuc
• The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-Period Planets
• Planets in Globular Clusters?
• Tests of In-Situ Formation Scenarios for Compact Multiplanet Systems
• The Frequency of Large Radius Hot and Very Hot Jupiters in omega Centauri
• Constraining Globular Cluster Age Uncertainties Using the IR Color-Magnitude Diagram

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• Zodiacal Exoplanets in Time (ZEIT) VII: A Temperate Candidate Super-Earth in the Hyades Cluster
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• Discovery of a Transiting Adolescent Sub-Neptune Exoplanet with K2
• Planets Across Space and Time (PAST). V. The evolution of hot Jupiters revealed by the age distribution of their host stars
• Another Shipment of Six Short-Period Giant Planets from TESS
• Searching For Transiting Planets Around Halo Stars. II. Constraining the Occurrence Rate of Hot Jupiters
• TOI-2046b, TOI-1181b and TOI-1516b, three new hot Jupiters from \textit{TESS}: planets orbiting a young star, a subgiant and a normal star
• The Influence of 10 Unique Chemical Elements in Shaping the Distribution of Kepler Planets
• How Complete Are Surveys for Nearby Transiting Hot Jupiters?
• Habitability in the Omega Centauri Cluster
• Occurrence rate of hot Jupiters orbiting red giant stars
• Probing the Survival of Planetary Systems in Globular Clusters with Tidal Disruption Events
• Photo-evaporation of proto-planetary gas discs due to flybys of external single stars in different orbits
• Planet Occurrence: Doppler and Transit Surveys
• A Search for Transiting Planets in the Globular Cluster M4 with K2: Candidates and Occurrence Limits
• Forming short period sub-stellar companions in 47 Tucanae -- II. Analytic expressions for the orbital evolution of planets in dense environments
• Radial velocity homogeneous analysis of M dwarfs observed with HARPS. II. Detection limits and planetary occurrence statistics
• Hot Jupiter formation in dense stellar clusters: A Monte Carlo model applied to 47 Tucanae
• Evidence for the Late Arrival of Hot Jupiters in Systems with High Host-star Obliquities
• The Multiband Imaging Survey for High-Alpha PlanetS (MISHAPS) I: Preliminary Constraints on the Occurrence Rate of Hot Jupiters in 47 Tucanae