Searching for Habitable Exoplanets with Relative Astrometry (SHERA). I. The Case for Searching for Planets in Binary Star Systems
Jessie L. Christiansen, Eric E. Mamajek, Gautam Vasisht, Catherine A. Clark, William Roberson, Eric L. Nielsen, Kaitlin M. Kratter, Juliette Becker, Eduardo Bendek, Ruslan Belikov, Alex Davis, Louis Desdoigts, Alyssa Jankowski, Michael R. Meyer, Benjamin J. S. Pope, Armen Tokadjian, Peter Tuthill
astro-ph.EP, astro-ph.IM
Submitted: 2026-08-04
Comments: Submitted to JATIS; re-submitted version after responding to referee comments
License: http://creativecommons.org/licenses/by/4.0/
The gist: Discovering Earth-like planets orbiting Sun-like stars was identified as a priority science goal of the Astronomy 2020 Decadal Survey.
Terminology
Abstract
Discovering Earth-like planets orbiting Sun-like stars was identified as a priority science goal of the Astronomy 2020 Decadal Survey. It is confounded by many factors, one of which is the high multiplicity of Sun-like stars in the local neighborhood - half of nearby Sun-like stars are in binary or higher-order stellar systems, which are less amenable to the detection of small planets with almost all of the currently productive exoplanet detection techniques. Here we describe the SHERA (Searching for Habitable Exoplanets with Relative Astrometry) NASA Small Explorer mission concept. SHERA utilizes diffractive-pupil technology on a small, simple optical space telescope to achieve microarcsecond precision relative astrometry on 14 Sun-like stars in seven nearby multi-star systems, combining the pupil and stellar binarity to provide a precise reference in the image plane. With this precision, SHERA would enable: (i) a search for rocky planets in the habitable zones of the closest Sun-like stars; (ii) an investigation of the impact of binary star formation on small, widely separated planets; and (iii) the performance of crucial precursor observations on a number of high-priority targets of NASA's future missions to characterize Earth-like planets, such as the Habitable Worlds Observatory. When combined with radial velocity measurements, SHERA relative astrometry will also enable exploration of the three-dimensional orbital structure of planets in binary systems.
Sources
- Precise Radial Velocities
- Extreme Precision Radial Velocity Working Group Final Report
- Roman Observations Time Allocation Committee: Final Report and Recommendations
- Habitable Worlds Observatory's Concept and Technology Maturation: Initial Feasibility and Trade Space Exploration
- NASA Exoplanet Exploration Program (ExEP) Mission Star List for the Habitable Worlds Observatory (2023)
- Radial Velocity Prospects Current and Future: A White Paper Report prepared by the Study Analysis Group 8 for the Exoplanet Program Analysis Group (ExoPAG)
- Differentiable Optics with dLux II: Optical Design Maximising Fisher Information
- A Century of Radial Velocity and Astrometric Monitoring of 70 Oph AB: New PFS Data and Constraints on Planetary Companions
Related papers
- PDS 70 c and SR 12 c: Observational Constraints on Giant-Planet and Satellite Formation
- Two-stage disruption of resonant chains
- Detectability of resolved hydrogen lines from the accretion shock at gas giants and their CPDs
- Binary-lens Microlensing Degeneracy: Impact on Planetary Sensitivity and Mass-ratio Function
- Atmospheric escape fractionates secondary but not primary atmospheres
- The Occurrence Rate of Nearby Planetary Companions to Hot Jupiters