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arXiv · 2512.09977

Decisively Demonstrating Roman CGI's TTR5 Requirement by Reimaging a Newly-Discovered Brown Dwarf Orbiting a Bright Accelerating Star

Thayne Currie·Mona El Morsy·Brianna Lacy·Masayuki Kuzuhara·Naoshi Murakami·Danielle Bovie
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Abstract

We propose Roman Coronagraph project HLC/575 nm observations of a newly-discovered brown dwarf (HIP 71618 B) from the Subaru/OASIS survey of young accelerating stars, which is supported by NASA headquarters with the directive to identify targets for the Roman Coronagraph that could fulfill TTR5 requirements and be observed during the technology demonstration phase. The target and multiple bright PSF references are within/close to the Roman Continuous Viewing Zone. A high SNR detection of this companion would singlehandedly fulfill TTR5 and would be the first optical detection of a companion at $<$10$^{-6}$ contrast. Roman CPP reference star vetting prioritizing stars that can be paired with HIP 71618 would aid the execution of a successful technology demonstration. Additional similar targets may be discovered from OASIS over the next few years that could increase CGI scheduling flexibility and enhance its scientific and technical return. A close collaborative partnership with the CPP team could ensure that they are schedulable.

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Thayne Currie, Mona El Morsy, Brianna Lacy, Masayuki Kuzuhara, Naoshi Murakami, Danielle Bovie. 2025-12-10. Decisively Demonstrating Roman CGI's TTR5 Requirement by Reimaging a Newly-Discovered Brown Dwarf Orbiting a Bright Accelerating Star. https://arxiv.org/abs/2512.09977

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