Binary-lens Microlensing Degeneracy: Impact on Planetary Sensitivity and Mass-ratio Function
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915629131366400 |
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| author | Shang, Yuxin Yang, Hongjing Zhang, Jiyuan Mao, Shude Gould, Andrew Zang, Weicheng Qian, Qiyue Yee, Jennifer C. |
| author_facet | Shang, Yuxin Yang, Hongjing Zhang, Jiyuan Mao, Shude Gould, Andrew Zang, Weicheng Qian, Qiyue Yee, Jennifer C. |
| contents | Gravitational microlensing is a unique method for discovering cold planets across a broad mass range. Reliable statistics of the microlensing planets require accurate sensitivity estimates. However, the impact of the degeneracies in binary-lens single-source (2L1S) models that affect many actual planet detections is often omitted in sensitivity estimates, leading to potential self-inconsistency of the statistics studies. In this work, we evaluate the effect of the 2L1S degeneracies on planetary sensitivity by simulating a series of typical microlensing events and comprehensively replicating a realistic planet detection pipeline, including the anomaly identification, global 2L1S model search, and degenerate model comparison. We find that for a pure-survey statistical sample, the 2L1S degeneracies reduce the overall planetary sensitivity by $5\sim10\%$, with the effect increasing at higher planet-host mass ratios. This bias leads to an underestimation of planet occurrence rates and a flattening of the inferred mass-ratio function slope. This effect will be critical for upcoming space-based microlensing surveys like the Roman or Earth 2.0 missions, which are expected to discover $\mathcal{O}(10^3)$ planets. We also discuss the computational challenges and propose potential approaches for future applications. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_16191 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Binary-lens Microlensing Degeneracy: Impact on Planetary Sensitivity and Mass-ratio Function Shang, Yuxin Yang, Hongjing Zhang, Jiyuan Mao, Shude Gould, Andrew Zang, Weicheng Qian, Qiyue Yee, Jennifer C. Earth and Planetary Astrophysics Astrophysics of Galaxies Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics Gravitational microlensing is a unique method for discovering cold planets across a broad mass range. Reliable statistics of the microlensing planets require accurate sensitivity estimates. However, the impact of the degeneracies in binary-lens single-source (2L1S) models that affect many actual planet detections is often omitted in sensitivity estimates, leading to potential self-inconsistency of the statistics studies. In this work, we evaluate the effect of the 2L1S degeneracies on planetary sensitivity by simulating a series of typical microlensing events and comprehensively replicating a realistic planet detection pipeline, including the anomaly identification, global 2L1S model search, and degenerate model comparison. We find that for a pure-survey statistical sample, the 2L1S degeneracies reduce the overall planetary sensitivity by $5\sim10\%$, with the effect increasing at higher planet-host mass ratios. This bias leads to an underestimation of planet occurrence rates and a flattening of the inferred mass-ratio function slope. This effect will be critical for upcoming space-based microlensing surveys like the Roman or Earth 2.0 missions, which are expected to discover $\mathcal{O}(10^3)$ planets. We also discuss the computational challenges and propose potential approaches for future applications. |
| title | Binary-lens Microlensing Degeneracy: Impact on Planetary Sensitivity and Mass-ratio Function |
| topic | Earth and Planetary Astrophysics Astrophysics of Galaxies Instrumentation and Methods for Astrophysics Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2509.16191 |