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The TESS light curve of AI Phoenicis

Maxted, P F L; Gaulme, Patrick; Graczyk, D; Hełminiak, K G; Johnston, C; Orosz, Jerome A; Prša, Andrej; Southworth, John; Torres, Guillermo; Davies, Guy R; Ball, Warrick; Chaplin, William J

The TESS light curve of AI Phoenicis Thumbnail


Patrick Gaulme

D Graczyk

K G Hełminiak

C Johnston

Jerome A Orosz

Andrej Prša

Guillermo Torres

Guy R Davies

Warrick Ball

William J Chaplin


Accurate masses and radii for normal stars derived from observations of detached eclipsing binary stars are of fundamental importance for testing stellar models and may be useful for calibrating free parameters in these model if the masses and radii are sufficiently precise and accurate. We aim to measure precise masses and radii for the stars in the bright eclipsing binary AI Phe, and to quantify the level of systematic error in these estimates. We use several different methods to model the TESS light curve of AI Phe combined with spectroscopic orbits from multiple sources to estimate precisely the stellar masses and radii together with robust error estimates. We find that the agreement between different methods for the light curve analysis is very good but some methods underestimate the errors on the model parameters. The semi-amplitudes of the spectroscopic orbits derived from spectra obtained with modern echelle spectrographs are consistent to within 0.1%. The masses of the stars in AI Phe are $M_1 = 1.1938 \pm 0.0008 M_{\odot}$ and $M_2 = 1.2438 \pm 0.0008M_{\odot}$, and the radii are $R_1 = 1.8050 \pm 0.0022 R_{\odot}$ and $R_2 = 2.9332 \pm 0.0023 R_{\odot}$. We conclude that it is possible to measure accurate masses and radii for stars in bright eclipsing binary stars to a precision of 0.2% or better using photometry from TESS and spectroscopy obtained with modern echelle spectrographs. We provide recommendations for publishing masses and radii of eclipsing binary stars at this level of precision.


Maxted, P. F. L., Gaulme, P., Graczyk, D., Hełminiak, K. G., Johnston, C., Orosz, J. A., …Chaplin, W. J. (2020). The TESS light curve of AI Phoenicis. Monthly Notices of the Royal Astronomical Society, 498(1), 332-343.

Journal Article Type Article
Acceptance Date Mar 20, 2020
Online Publication Date Jun 12, 2020
Publication Date 2020-10
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 498
Issue 1
Pages 332-343
Keywords stars: solar-type – stars: fundamental parameters – binaries: eclipsing
Publisher URL


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