Habitable Zones for Earth-mass Planets in Multiple Planetary Systems

TL;DR

This study uses numerical simulations to identify stable habitable zones and dynamical structures for Earth-mass planets in systems like HD 69830, highlighting resonance effects and potential regions for terrestrial planets.

Contribution

It provides detailed dynamical analysis of habitable zones in multi-planet systems, especially focusing on the influence of orbital resonances and asteroid belt structures.

Findings

Stable zones for Earth-mass planets between 0.3-0.5 AU and 0.8-1.2 AU.

Resonance effects shape asteroid belt structures.

Potential habitable regions identified with low eccentricities.

Abstract

We perform numerical simulations to study the Habitable zones (HZs) and dynamical structure for Earth-mass planets in multiple planetary systems. For example, in the HD 69830 system, we extensively explore the planetary configuration of three Neptune-mass companions with one massive terrestrial planet residing in 0.07 AU $\leq a \leq$ 1.20 AU, to examine the asteroid structure in this system. We underline that there are stable zones of at least $10^5$ yr for low-mass terrestrial planets locating between 0.3 and 0.5 AU, and 0.8 and 1.2 AU with final eccentricities of $e < 0.20$. Moreover, we also find that the accumulation or depletion of the asteroid belt are also shaped by orbital resonances of the outer planets, for example, the asteroidal gaps at 2:1 and 3:2 mean motion resonances (MMRs) with Planet C, and 5:2 and 1:2 MMRs with Planet D. In a dynamical sense, the proper candidate regions for the existence of the potential terrestrial planets or HZs are 0.35 AU $< a < $ 0.50 AU, and 0.80 AU $< a < $ 1.00 AU for relatively low eccentricities, which makes sense to have the possible asteroidal structure in this system.