Planetesimal Accretion in Binary Systems: Could Planets Form Around Alpha Centauri B ?

TL;DR

This study investigates the potential for planetesimal accretion around Alpha Centauri B, considering binary perturbations, gas conditions, and inclinations, and finds that Earth-like planets could form there but not gaseous giants.

Contribution

A simplified scaling method was developed to estimate planetesimal accretion timescales in binary systems, applied specifically to Alpha Centauri B.

Findings

Earth-like planet formation is possible around Alpha Centauri B.

Gaseous giant planet formation is unlikely in this system.

Binary inclination and gas density significantly influence accretion conditions.

Abstract

Stellar perturbations affect planet-formation in binary systems. Recent studies show that the planet-formation stage of mutual accretion of km-sized planetesimals is most sensitive to binary effects. In this paper, the condition for planetesimal accretion is investigated around Alpha CenB, which is believed to be an ideal candidate for detection of an Earth-like planet in or near its habitable zone(0.5-0.9 AU). A simplified scaling method is developed to estimate the accretion timescale of the planetesimals embedded in a protoplanetary disk. Twenty-four cases with different binary inclinations(i_B=0, 0.1, 1.0, and 10 deg), gas densities(0.3,1,and 3 times of the Minimum Mass of Solar Nebula, MMSN hereafter), and with and without gas depletion, are simulated. We find: (1)...(2)...(3)...(4)...(see the paper for details). In other words, our results suggest that formation of Earth-like planets through accretion of km-sized planetesimals is possible in Alpha CenB, while formation of gaseous giant planets is not favorable.