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arXiv · 2608.17057

The Roman Coronagraph Community Participation Program: pre-launch reference star list and impact of reference star properties on post-processing performance

Justin Hom·Schuyler G. Wolff·Jessica Gersh-Range·Ramya M. Anche·Vanessa P. Bailey·Jean-Philippe Berger·Beth A. Biller·Wolfgang Brandner·Marah Brinjikji·Gaël Chauvin·David R. Ciardi·Catherine A. Clark·Laird M. Close·Robert J. De Rosa·Sarah Deveny·Warren B. Foster·Julien H. Girard·Alexandra Z. Greenbaum·Olivier Guyon·Sebastiaan Y. Haffert·Alexander D. Hedglen·Steve B. Howell·Parker T. Johnson·Maggie Y. Kautz·Jay K. Kueny·Masayuki Kuzuhara·Manon Lallement·Rico Landman·Colin Littlefield·Jean-Baptiste Le Bouquin·Jialin Li·Joshua Liberman·Joseph D. Long·Miles Lucas·Jennifer Lumbres·Bruce Macintosh·Jared R. Males·Eric Mamajek·Matthijs Mars·Eden A. McEwen·Avalon L. McLeod·Maxwell A. Millar-Blanchaer·Toshiyuki Mizuki·Sophie Noiret·Tiffany Nguyen·Lauren Schatz·Nicholas T. Schragal·Adam K. Taras·Elena Tonucci·Katie Twitchell·Kyle Van Gorkom·Macarena C. Vega-Pallauta·Jason J. Wang·Jingwen Zhang
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Abstract

The upcoming Roman Coronagraph will be the first high-contrast instrument in space capable of high-order wavefront sensing and control technologies, a critical technology demonstration for the proposed Habitable Worlds Observatory (HWO) that aims to directly image and characterize habitable exoEarths. The nominal Roman Coronagraph observing plan involves alternating observations of a science target and a bright, nearby reference star for both wavefront calibration and reference differential imaging post-processing. Reference star criteria for the most demanding coronagraph mode are restrictive, limiting the sample to only 40 candidates for which thorough observational vetting is needed to assess their suitability. Reference star properties such as resolved diameters, presence of circumstellar dust, and close point sources may also have more subtle impacts on post-processing efficacy that may inhibit final contrast performance. In this work, we describe the current progress of the CoronaGraph Instrument Reference stars for Exoplanets (CorGI-REx) observing campaign, a 300+-hour observing campaign that utilizes instruments from around the world to vet reference stars for high-order wavefront control suitability. We will present the pre-launch list of reference star candidates being utilized for the Roman Coronagraph Observation Phase constructed from a thorough analysis of high contrast and interferometric observations. We will also present the results of simulations investigating the impact of reference star resolved diameters and companions on post-processing performance. We conclude by discussing the importance of reference star selection for scheduling observations and optimizing contrast performance for the Roman Coronagraph along with implications for HWO coronagraph operations.

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Justin Hom, Schuyler G. Wolff, Jessica Gersh-Range, Ramya M. Anche, Vanessa P. Bailey, Jean-Philippe Berger, Beth A. Biller, Wolfgang Brandner, Marah Brinjikji, Gaël Chauvin, David R. Ciardi, Catherine A. Clark, Laird M. Close, Robert J. De Rosa, Sarah Deveny, Warren B. Foster, Julien H. Girard, Alexandra Z. Greenbaum, Olivier Guyon, Sebastiaan Y. Haffert, Alexander D. Hedglen, Steve B. Howell, Parker T. Johnson, Maggie Y. Kautz, Jay K. Kueny, Masayuki Kuzuhara, Manon Lallement, Rico Landman, Colin Littlefield, Jean-Baptiste Le Bouquin, Jialin Li, Joshua Liberman, Joseph D. Long, Miles Lucas, Jennifer Lumbres, Bruce Macintosh, Jared R. Males, Eric Mamajek, Matthijs Mars, Eden A. McEwen, Avalon L. McLeod, Maxwell A. Millar-Blanchaer, Toshiyuki Mizuki, Sophie Noiret, Tiffany Nguyen, Lauren Schatz, Nicholas T. Schragal, Adam K. Taras, Elena Tonucci, Katie Twitchell, Kyle Van Gorkom, Macarena C. Vega-Pallauta, Jason J. Wang, Jingwen Zhang. 2026-08-17. The Roman Coronagraph Community Participation Program: pre-launch reference star list and impact of reference star properties on post-processing performance. https://arxiv.org/abs/2608.17057

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