2006/01/31 by Byeong-Gon Park, Byeong‐Gon Park, Young‐Beom Jeon +4
Physics and Astronomy · #Astronomy and Astrophysical Research #Circumstellar habitable zone #Exoplanet #Gravitational microlensing #Planet #Planetary habitability #Planetary system #RADIUS #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/503187
published as Astrophys.J. 643 (2006) 1233-1238 · ApJ, submitted
arxiv created 2006/01/31 · openalex publication_date 2006/06/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Microlensing is one of the most powerful methods that can detect extrasolar planets, and a future space-based survey with a high monitoring frequency is proposed to detect a large sample of Earth-mass planets. In this paper, we examine the sensitivity of the future microlensing survey to Earth-mass planets located in the habitable zone. For this, we estimate the fraction of Earth-mass planets that will be located in the habitable zone of their parent stars by carrying out a detailed simulation of microlensing events based on standard models of the physical and dynamic distributions and the mass function of Galactic matter. From this investigation, we find that among the total detectable Earth-mass planets from the survey, those located in the habitable zone would comprise less than 3% even under a less conservative definition of the habitable zone. We find that the main reason for the low sensitivity is the projected star-planet separation at which the microlensing planet detection efficiency becomes maximum (lensing zone) is in most cases substantially larger than the median value of the habitable zone. We find that the ratio of the median radius of the habitable zone to the mean radius of the lensing zone is roughly expressed as d HZ / r E ~ 0.2( m /0.5 M ☉ ) 1/2 .