CHEPS cold Jupiters RV curves

Our analysis confirms and characterises orbital parameters for two known planets in HIP 21850 and detects five new planets: a warm Jupiter -- HIP 10090c, with orbital period P=321.8^+0.3^_-0.6_d and mass M=0.85^+0.03^_-0.12_M_J_, and four Jupiter analogues -- HIP 8923b with P=14.1^+0.4^_-0.7_yr and M=9.98^+0.78^_-0.16_M_J_, HIP 10090b with P=8.1^+0.3^_-0.3_yr and M=3.87^+0.65^_-0.60_M_J_, HIP 39330b with P=12.7^+0.6^_-0.7_yr and M=1.68^+0.16^_-0.13_M_J_, and HIP 98599b with P=7.3^+0.1^_-0.1_yr and M=6.85^+0.10^_-0.22_M_J_.

Adding astrometry reduces period and mass uncertainties by factors between 3 and 10, whilst increasing the Bayes' factors by up to ~60. The synergy of long-baseline RVs and absolute astrometry provides a robust pathway to discover and characterise cold giant planets and metal-rich Solar-System analogues. Our results demonstrate that astrometric samples meaningfully improve detection confidence and convert minimum masses into true masses.

This approach fills the demographic gap between RV and direct imaging sensitivities and prepares the field for forthcoming astrometric missions that will allow to find stellar systems like our own.