Exoplanetology: Exoplanets & Exomoons

Closeby Habitable Exoplanet Survey (CHES). IV. Synergy Between Astrometry and Direct Imaging Missions of the Habitable World Observatory for Detecting Earth-like Planets

By Keith Cowing

Status Report

astro-ph.EP

May 6, 2025

Filed under astro-ph.EP, astronomy, atmosphere, biosignature, Closeby Habitable Exoplanet Survey (CHES), exoplanet, Habitable Worlds Observatory, Habitable Zone, imaging, Spectroscopy, telescope

Closeby Habitable Exoplanet Survey (CHES). IV. Synergy Between Astrometry and Direct Imaging Missions of the Habitable World Observatory for Detecting Earth-like Planets — Stellar properties of HWO targets from Harada et al. (2024) and the astrometric and imaging signals contours. The orange, red, blue circle and black points represent stars with known planets, binary stars, single stars and common targets of CHES, respectively. Left panel: Stellar luminosity versus distance of all targets. The olive solid, green dashed and red dash-dotted line represent α = 1.0, 0.3, 0.1 µas in the scenario of a planet with one Earth mass located at the the center of the habitable zone, the logarithmic relation between stellar mass and luminosity is adopted for drawing the curves (Eker et al. 2015). Right panel: Effective temperature versus luminosity, and the horizontal lines corresponds to different imaging contrast. — astro-ph.EP

The detection and characterization of habitable planets around nearby stars persist as one of the foremost objectives in contemporary astrophysics. This work investigates the synergistic integration of astrometric and direct imaging techniques by capitalizing on the complementary capabilities of the Closeby Habitable Exoplanet Survey (CHES) and Habitable Worlds Observatory (HWO).

Planetary brightness and position vary over time due to phase effects and orbital architectures, information that can be precisely provided by CHES’s astrometric measurements. By combining the precise orbital constraints from CHES with the imaging capabilities of HWO, we evaluate the improvements in detection efficiency, signal-to-noise ratio and overall planet yield.

Completeness is quantified as the fraction of injected planets that are successfully detected, while yields are estimated for various scenarios using terrestrial planet occurrence rates derived from the Kepler dataset. Our results indicate that prior astrometric data significantly enhance detection efficiency.

Under the adopted detection limit, our analysis indicates that prior CHES observations can increase completeness by approximately 10% and improve detection efficiency by factors ranging from two to thirty. The findings underscore the importance of interdisciplinary approaches in the search for and characterization of habitable worlds.

Chunhui Bao, Jianghui Ji, Dongjie Tan, Guo Chen, Xiumin Huang, Su Wang, Yao Dong

Comments: 22 pages, 9 figures, accepted for publication in AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2505.02818 [astro-ph.EP] (or arXiv:2505.02818v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.02818
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Submission history
From: Jianghui Ji
[v1] Mon, 5 May 2025 17:46:03 UTC (384 KB)
https://arxiv.org/abs/2505.02818

Astrobiology

Keith Cowing

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) 🖖🏻

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