Proxima Centauri's Angular Diameter Revisited
Abstract
Proxima Centauri is the nearest known exoplanet-hosting star and a benchmark for low-mass stellar models. Published diameters differ by several percent, affecting its inferred radius and temperature. Model-dependent near-infrared limb darkening introduces an additional 2-5% correction to the inferred radius. We re-reduced two previously published VLTI/PIONIER interferometric epochs from 2014 and combined them with three previously unpublished archival epochs from 2017 and 2019. We fit all five data sets jointly with uniform-disk and atmosphere-grid-based center-to-limb models. The joint fit gives a uniform-disk angular diameter, θUD=1.117±0.024 mas. Using the PHOENIX model and adopted bolometric flux, we obtain a PHOENIX limb-darkened angular diameter, θLD,PHX=1.154±0.026 mas, a stellar radius, R⋆=0.162±0.004 R⊙, and a Stefan--Boltzmann effective temperature, Teff,SB=2833±49 K. No significant close companion is detected across the five epochs over the searched separation and contrast range.
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BibTeX
@misc{anugu2026proxima,
title = {{Proxima Centauri's Angular Diameter Revisited}},
author = {Narsireddy Anugu and Alexandre Gallenne and Pierre Kervella and Adam D. Rains},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.33373},
eprint = {2610.33373},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.33373},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Proxima Centauri's Angular Diameter Revisited
AU - Narsireddy Anugu
AU - Alexandre Gallenne
AU - Pierre Kervella
AU - Adam D. Rains
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.33373
UR - https://arxiv.org/abs/2610.33373
AB - Proxima Centauri is the nearest known exoplanet-hosting star and a benchmark for low-mass stellar models. Published diameters differ by several percent, affecting its inferred radius and temperature. Model-dependent near-infrared limb darkening introduces an additional 2-5% correction to the inferred radius. We re-reduced two previously published VLTI/PIONIER interferometric epochs from 2014 and combined them with three previously unpublished archival epochs from 2017 and 2019. We fit all five data sets jointly with uniform-disk and atmosphere-grid-based center-to-limb models. The joint fit gives a uniform-disk angular diameter, θ_UD=1.117±0.024 mas. Using the PHOENIX model and adopted bolometric flux, we obtain a PHOENIX limb-darkened angular diameter, θ_LD,PHX=1.154±0.026 mas, a stellar radius, R_⋆=0.162±0.004 R_⊙, and a Stefan--Boltzmann effective temperature, T_eff,SB=2833±49 K. No significant close companion is detected across the five epochs over the searched separation and contrast range.
ER -