We report the light-curve analysis for the event MOA-2020-BLG-135, which leads to the discovery of a new Neptune-class planet, MOA-2020-BLG-135Lb. With a derived mass ratio of q=1.52−0.31+0.39×10−4 and separation s≈1, the planet lies exactly at the break and likely peak of the exoplanet mass-ratio function derived by the MOA collaboration (Suzuki et al. 2016). We estimate the properties of the lens system based on a Galactic model and considering two different Bayesian priors: one assuming that all stars have an equal planet-hosting probability and the other that planets are more likely to orbit more massive stars. With a uniform host mass prior, we predict that the lens system is likely to be a planet of mass mplanet=11.3−6.9+19.2M⊕ and a host star of mass Mhost=0.23−0.14+0.39M⊙, located at a distance DL=7.9−1.0+1.0kpc. With a prior that holds that planet occurrence scales in proportion to the host star mass, the estimated lens system properties are mplanet=25−15+22M⊕, Mhost=0.53−0.32+0.42M⊙, and DL=8.3−1.0+0.9kpc. This planet qualifies for inclusion in the extended MOA-II exoplanet microlens sample.
@article{arxiv.2204.03672,
title = {MOA-2020-BLG-135Lb: A New Neptune-class Planet for the Extended MOA-II Exoplanet Microlens Statistical Analysis},
author = {Stela Ishitani Silva and Clément Ranc and David P. Bennett and Ian A. Bond and Weicheng Zang and Fumio Abe and Richard K. Barry and Aparna Bhattacharya and Hirosane Fujii and Akihiko Fukui and Yuki Hirao and Yoshitaka Itow and Rintaro Kirikawa and Iona Kondo and Naoki Koshimoto and Yutaka Matsubara and Sho Matsumoto and Shota Miyazaki and Yasushi Muraki and Greg Olmschenk and Arisa Okamura and Nicholas J. Rattenbury and Yuki Satoh and Takahiro Sumi and Daisuke Suzuki and Taiga Toda and Paul . J. Tristram and Aikaterini Vandorou and Hibiki Yama and Andreea Petric and Todd Burdullis and Pascal Fouqué and Shude Mao and Matthew T. Penny and Wei Zhu and Gioia Rau},
journal= {arXiv preprint arXiv:2204.03672},
year = {2025}
}