Exoplanets & Exomoons

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

By Keith Cowing
Status Report
March 20, 2024
Filed under , , , , , ,
Unveiling MOA-2007-BLG-192: An M Dwarf Hosting a Likely Super-Earth
Top Left: The co-added sum of 15 Keck NIRC2 narrow camera images, each with an exposure time of 60 seconds. The target is indicated with a square outline. Top Right: Zoomed image of the MB07192 blended source and lens stars. The magnitude of the separation in this epoch is 29.3 ± 1.1 mas. Bottom Left: The residual image from a single-star PSF fit with DAOPHOT. A clear signal is seen due to the blended stellar profiles. Bottom Right: The residual image for a simultaneous two-star PSF fit, showing a significantly improved subtraction. The color bar represents the pixel intensity (or counts) in the bottom panel residual images. — astro-ph.EP

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 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. 2023, we apply constraints from the high resolution imaging on the light curve modeling to find host star and planet masses of Mhost=0.28±0.04M and mp=12.49+65.47−8.03M at a distance from Earth of DL=2.16±0.30kpc.

This work illustrates the necessity for the Nancy Grace Roman Galactic Exoplanet Survey (RGES) to use its own high resolution imaging to inform light curve modeling for microlensing planets that the mission discovers.

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

Comments: 26 pages, 10 figures, submitted to AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2403.12118 [astro-ph.EP] (or arXiv:2403.12118v1 [astro-ph.EP] for this version)
Submission history
From: Sean Terry
[v1] Mon, 18 Mar 2024 18:00:00 UTC (9,361 KB)


Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻