KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed due to source binarity

Authors

Cheongho Han, Chungbuk National University
Weicheng Zang, Harvard-Smithsonian Center for Astrophysics
Youn Kil Jung, Korea Astronomy and Space Science Institute
Ian A. Bond, Massey University Auckland
Sun Ju Chung, Harvard-Smithsonian Center for Astrophysics
Michael D. Albrow, University of Canterbury
Andrew Gould, Max Planck Institute for Astronomy
Kyu Ha Hwang, Korea Astronomy and Space Science Institute
Yoon Hyun Ryu, Korea Astronomy and Space Science Institute
In Gu Shin, Harvard-Smithsonian Center for Astrophysics
Yossi Shvartzvald, Weizmann Institute of Science Israel
Hongjing Yang, Tsinghua University
Jennifer C. Yee, Harvard-Smithsonian Center for Astrophysics
Sang Mok Cha, Korea Astronomy and Space Science Institute
Doeon Kim, Chungbuk National University
Dong Jin Kim, Korea Astronomy and Space Science Institute
Seung Lee Kim, Korea Astronomy and Space Science Institute
Chung Uk Lee, Korea Astronomy and Space Science Institute
Dong Joo Lee, Korea Astronomy and Space Science Institute
Yongseok Lee, Korea Astronomy and Space Science Institute
Byeong Gon Park, Korea Astronomy and Space Science Institute
Richard W. Pogge, The Ohio State University
Berto Monard, Bronberg Observatory
Qiyue Qian, Tsinghua University
Zhuokai Liu, Peking University
Dan Maoz, Tel Aviv University
Matthew T. Penny, Louisiana State University
Wei Zhu, Tsinghua University
Fumio Abe, Nagoya University
Richard Barry, NASA Goddard Space Flight Center
David P. Bennett, NASA Goddard Space Flight Center
Aparna Bhattacharya, NASA Goddard Space Flight Center
Hirosame Fujii, Nagoya University

Document Type

Article

Publication Date

10-1-2023

Abstract

Aims. We investigate the previous microlensing data collected by the KMTNet survey in search of anomalous events for which no precise interpretations of the anomalies had been suggested. From this investigation, we find that the anomaly in the lensing light curve of the event KMT-2021-BLG-1547 is approximately described by a binary-lens (2L1S) model with a lens possessing a giant planet, but the model leaves unexplained residuals. Methods. We investigated the origin of the residuals by testing more sophisticated models that include either an extra lens component (3L1S model) or an extra source star (2L2S model) on top of the 2L1S configuration of the lens system. From these analyses, we find that the residuals from the 2L1S model originate from the existence of a faint companion to the source. The 2L2S solution substantially reduces the residuals and improves the model fit by δ x ² = 67.1 with respect to the 2L1S solution. The 3L1S solution also improves the fit, but its fit is worse than that of the 2L2S solution by δ x ² = 24.7. Results. According to the 2L2S solution, the lens of the event is a planetary system with planet and host masses (Mp/MJ, Mh/M·) = (1.47-0.77^+0.64, 0.72-0.38^+0.32) lying at a distance DL = 5.07-1.50^+0.98 kpc, and the source is a binary composed of a subgiant primary of a late G or an early K spectral type and a main-sequence companion of a K spectral type. The event demonstrates the need for sophisticated modeling of unexplained anomalies if one wants to construct a complete microlensing planet sample.

Publication Source (Journal or Book title)

Astronomy and Astrophysics

Recommended Citation

Han, C., Zang, W., Jung, Y., Bond, I., Chung, S., Albrow, M., Gould, A., Hwang, K., Ryu, Y., Shin, I., Shvartzvald, Y., Yang, H., Yee, J., Cha, S., Kim, D., Kim, D., Kim, S., Lee, C., Lee, D., Lee, Y., Park, B., Pogge, R., Monard, B., Qian, Q., Liu, Z., Maoz, D., Penny, M., Zhu, W., Abe, F., Barry, R., Bennett, D., Bhattacharya, A., & Fujii, H. (2023). KMT-2021-BLG-1547Lb: Giant microlensing planet detected through a signal deformed due to source binarity. Astronomy and Astrophysics, 678 https://doi.org/10.1051/0004-6361/202347366