Measurement of Dependence of Microlensing Planet Frequency on The Host Star Mass and Galactocentric Distance by using a Galactic Model

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Hauptverfasser: Nunota, Kansuke, Koshimoto, Naoki, Suzuki, Daisuke, Sumi, Takahiro, Bennett, David P., Bhattacharya, Aparna, Hirao, Yuki, Terry, Sean K., Vandorou, Aikaterini
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Veröffentlicht: 2024
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author Nunota, Kansuke
Koshimoto, Naoki
Suzuki, Daisuke
Sumi, Takahiro
Bennett, David P.
Bhattacharya, Aparna
Hirao, Yuki
Terry, Sean K.
Vandorou, Aikaterini
author_facet Nunota, Kansuke
Koshimoto, Naoki
Suzuki, Daisuke
Sumi, Takahiro
Bennett, David P.
Bhattacharya, Aparna
Hirao, Yuki
Terry, Sean K.
Vandorou, Aikaterini
contents We measure the dependence of planet frequency on host star mass, $M_{\rm L}$, and distance from the Galactic center, $R_{\rm L}$, using a sample of planets discovered by gravitational microlensing. We compare the two-dimensional distribution of the lens-source proper motion, $μ_{\rm rel}$, and the Einstein radius crossing time, $t_{\rm E}$, measured for 22 planetary events from Suzuki et al. (2016) with the distribution expected from Galactic model. Assuming that the planet-hosting probability of a star is proportional to $M_{\rm L}^m R_{\rm L}^r$, we calculate the likelihood distribution of $(m,r)$. We estimate that $r = 0.10^{+0.51}_{-0.37}$ and $m = 0.50^{+0.90}_{-0.70}$ under the assumption that the planet-hosting probability is independent of the mass ratio. We also divide the planet sample into subsamples based on their mass ratio, $q$, and estimate that $m=-0.08^{+0.95}_{-0.65}$ for $q < 10^{-3}$ and $1.25^{+1.07}_{-1.14}$ for $q > 10^{-3}$. Although uncertainties are still large, this result implies a possibility that in orbits beyond the snowline, massive planets are more likely to exist around more massive stars whereas low-mass planets exist regardless of their host star mass.
format Preprint
id arxiv_https___arxiv_org_abs_2403_01721
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Measurement of Dependence of Microlensing Planet Frequency on The Host Star Mass and Galactocentric Distance by using a Galactic Model
Nunota, Kansuke
Koshimoto, Naoki
Suzuki, Daisuke
Sumi, Takahiro
Bennett, David P.
Bhattacharya, Aparna
Hirao, Yuki
Terry, Sean K.
Vandorou, Aikaterini
Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
We measure the dependence of planet frequency on host star mass, $M_{\rm L}$, and distance from the Galactic center, $R_{\rm L}$, using a sample of planets discovered by gravitational microlensing. We compare the two-dimensional distribution of the lens-source proper motion, $μ_{\rm rel}$, and the Einstein radius crossing time, $t_{\rm E}$, measured for 22 planetary events from Suzuki et al. (2016) with the distribution expected from Galactic model. Assuming that the planet-hosting probability of a star is proportional to $M_{\rm L}^m R_{\rm L}^r$, we calculate the likelihood distribution of $(m,r)$. We estimate that $r = 0.10^{+0.51}_{-0.37}$ and $m = 0.50^{+0.90}_{-0.70}$ under the assumption that the planet-hosting probability is independent of the mass ratio. We also divide the planet sample into subsamples based on their mass ratio, $q$, and estimate that $m=-0.08^{+0.95}_{-0.65}$ for $q < 10^{-3}$ and $1.25^{+1.07}_{-1.14}$ for $q > 10^{-3}$. Although uncertainties are still large, this result implies a possibility that in orbits beyond the snowline, massive planets are more likely to exist around more massive stars whereas low-mass planets exist regardless of their host star mass.
title Measurement of Dependence of Microlensing Planet Frequency on The Host Star Mass and Galactocentric Distance by using a Galactic Model
topic Earth and Planetary Astrophysics
Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2403.01721