Unveiling MOA-2007-BLG-192: An M Dwarf Hosting a Likely Super-Earth

Creators: Terry, Sean K.; Beaulieu, Jean-Philippe; Bennett, David P.; Hamdorf, Euan; Bhattacharya, Aparna; Chaudhry, Viveka; Cole, Andrew A.; Koshimoto, Naoki; Anderson, Jay; Bachelet, Etienne; Blackman, Joshua W.; Bond, Ian A.; Lu, Jessica R.; Marquette, Jean Baptiste; Ranc, Clément; Rektsini, Natalia E.; Sahu, Kailash; Vandorou, Aikaterini

Abstract

Abstract We present an analysis of high-angular-resolution images of the microlensing target MOA-2007-BLG-192 using Keck adaptive optics and the Hubble Space Telescope. The planetary host star is robustly detected as it separates from the background source star in nearly all of the Keck and Hubble data. The amplitude and direction of the lens–source separation allows us to break a degeneracy related to the microlensing parallax and source radius crossing time. Thus, we are able to reduce the number of possible binary-lens solutions by a factor of ∼2, demonstrating the power of high-angular-resolution follow-up imaging for events with sparse light-curve coverage. Following Bennett et al., we apply constraints from the high-resolution imaging on the light-curve modeling to find host star and planet masses of M host = 0.28 ± 0.04 M ☉ and m p = 12.49 − 8.03 + 65.47 M ⊕ at a distance from Earth of D L = 2.16 ± 0.30 kpc. This work illustrates the necessity for the Nancy Grace Roman Galactic Exoplanet Survey to use its own high-resolution imaging to inform light-curve modeling for microlensing planets that the mission discovers.

Copyright and License

© 2024. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

The authors would like to thank the anonymous referee for helpful comments that improved the structure and led to a stronger manuscript. This paper is based in part on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. The Keck Telescope observations and data analysis were supported by a NASA Keck PI Data Award, grant No. 80NSSC18K0793, administered by the NASA Exoplanet Science Institute. All of the HST data used in this paper can be found in MAST: 10.17909/wbe0-3a21. Data presented herein were obtained at the W. M. Keck Observatory from telescope time allocated to the National Aeronautics and Space Administration through the agency's scientific partnership with the California Institute of Technology and the University of California. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. The material presented here is also based upon work supported by NASA under grant No. 80GSFC21M0002. This work was supported by the University of Tasmania through the UTAS Foundation and the endowed Warren Chair in Astronomy and the ANR COLD-WORLDS (grant No. ANR-18-CE31-0002). Part of this work was authored by employees of Caltech/IPAC under Contract No. 80GSFC21R0032 with the National Aeronautics and Space Administration. Lastly, portions of this research were supported by the Australian Government through an Australian Research Council Discovery Program (project No. 200101909) grant awarded to A.C. and J.P.B.

Software References

DAOPHOT-II (Stetson 1987), daophot _ mcmc (Terry et al. 2021), eesunhong (Bennett & Rhie 1996), emcee (Foreman-Mackey et al. 2013), genulens (Koshimoto & Ranc 2021), hst1pass (Anderson 2022), KAI (Lu 2022), Matplotlib (Hunter 2007), Numpy (Oliphant 2006), Spyctres (Bachelet 2024), SWarp (Bertin 2010)

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