MOA-2022-BLG-249Lb: Nearby microlensing super-Earth planet detected from high-cadence surveys

¹ Department of Physics, Chungbuk National University, Cheongju 28644, Republic of Korea
e-mail: cheongho@astroph.chungbuk.ac.kr
² Max-Planck-Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
³ Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210, USA
⁴ Korea Astronomy and Space Science Institute, Daejon 34055, Republic of Korea
⁵ Korea University of Science and Technology, Korea, (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon, 34113, Republic of Korea
⁶ Institute of Natural and Mathematical Science, Massey University, Auckland 0745, New Zealand
⁷ Center for Astrophysics, Harvard & Smithsonian, 60 Garden St., Cambridge, MA 02138, USA
⁸ Department of Astronomy, Tsinghua University, Beijing 100084, PR China
⁹ University of Canterbury, Department of Physics and Astronomy, Private Bag 4800, Christchurch 8020, New Zealand
¹⁰ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
¹¹ School of Space Research, Kyung Hee University, Yongin, Kyeonggi 17104, Republic of Korea
¹² Institute for Space-Earth Environmental Research, Nagoya University, Nagoya 464-8601, Japan
¹³ Code 667, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
¹⁴ Department of Astronomy, University of Maryland, College Park, MD 20742, USA
¹⁵ Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
¹⁶ Instituto de Astrofísica de Canarias, Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
¹⁷ Department of Earth and Space Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
¹⁸ Department of Physics, The Catholic University of America, Washington, DC 20064, USA
¹⁹ Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
²⁰ Sorbonne Université, CNRS, UMR 7095, Institut d'Astrophysique de Paris, 98 bis bd Arago, 75014 Paris, France
²¹ Department of Physics, University of Auckland, Private Bag 92019, Auckland, New Zealand
²² University of Canterbury Mt. John Observatory, PO Box 56, Lake Tekapo 8770, New Zealand

Received: 16 February 2023
Accepted: 5 April 2023

Abstract

Aims. We investigate the data collected by the high-cadence microlensing surveys during the 2022 season in search of planetary signals appearing in the light curves of microlensing events. From this search, we find that the lensing event MOA-2022-BLG-249 exhibits a brief positive anomaly that lasted for about one day, with a maximum deviation of ~0.2 mag from a single-source, single-lens model.

Methods. We analyzed the light curve under the two interpretations of the anomaly: one originated by a low-mass companion to the lens (planetary model) and the other originated by a faint companion to the source (binary-source model).

Results. We find that the anomaly is better explained by the planetary model than the binary-source model. We identified two solutions rooted in the inner-outer degeneracy and for both of them, the estimated planet-to-host mass ratio, q ~ 8 × 10⁻⁵, is very small. With the constraints provided by the microlens parallax and the lower limit on the Einstein radius, as well as the blend-flux constraint, we find that the lens is a planetary system, in which a super-Earth planet, with a mass of (4.83 ± 1.44) Μ_⊕, orbits a low-mass host star, with a mass of (0.18 ± 0.05) M_⊙, lying in the Galactic disk at a distance of (2.00 ± 0.42) kpc. The planet detection demonstrates the elevated microlensing sensitivity of the current high-cadence lensing surveys to low-mass planets.