Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search

TL;DR

This study reveals that Cool Jupiters, similar to our Solar system's giants, are significantly more common than hot Jupiters, with occurrence rates around 6.7%, based on 18 years of data from the Anglo-Australian Planet Search.

Contribution

It provides the first comprehensive occurrence rate estimate of Cool Jupiters using long-term radial velocity data, highlighting their abundance compared to hot Jupiters.

Findings

Cool Jupiters occur at a rate of approximately 6.7%.

Hot Jupiters have an occurrence rate of about 0.8%.

Giant planet occurrence is constant beyond 1 au.

Abstract

Our understanding of planetary systems different to our own has grown dramatically in the past 30 years. However, our efforts to ascertain the degree to which the Solar system is abnormal or unique have been hindered by the observational biases inherent to the methods that have yielded the greatest exoplanet hauls. On the basis of such surveys, one might consider our planetary system highly unusual - but the reality is that we are only now beginning to uncover the true picture. In this work, we use the full eighteen-year archive of data from the Anglo-Australian Planet Search to examine the abundance of 'Cool Jupiters' - analogs to the Solar system's giant planets, Jupiter and Saturn. We find that such planets are intrinsically far more common through the cosmos than their siblings, the hot Jupiters. We find that the occurrence rate of such 'Cool Jupiters' is $6.73^{+2.09}_{-1.13}$\%, almost an order of magnitude higher than the occurrence of hot Jupiters (at $0.84^{+0.70}_{-0.20}$\%). We also find that the occurrence rate of giant planets is essentially constant beyond orbital distances of $\sim$1\,au. Our results reinforce the importance of legacy radial velocity surveys for the understanding of the Solar system's place in the cosmos.