Planets around metal-poor stars

These produce trustworthy numbers for the planet frequency. A general Lomb Scargle (GLS) periodogram analysis was used together with a bootstrapping method to produce the detection limits. Planet frequencies were calculated based on a binomial distribution function within metallicity bins.

Almost all hot Jupiters and most giant planets should have been found in these data. Hot Jupiters around metal-poor stars have a frequency lower than 1.0% at one sigma. Giant planets with periods up to 1800 days, however, have a higher frequency of 2.63^+2.5^_-0.89_%.

Taking into account the different metallicities of the stars, we show that giant planets appear to be very frequent (4.48^+4.04^_-1.38_%) around stars with [Fe/H]>-0.7, while they are rare around stars with [Fe/H]<-0.7. We conclude that giant planet frequency is indeed a strong function of metallicity, even in the low-metallicity tail. However, the frequencies are most likely higher than previously thought.