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# The Pre-Main-Sequence Eclipsing Binary TY Coronae Australis: Precise Stellar Dimensions and Tests of Evolutionary Models

Casey, Brian W.; Mathieu, Robert D.; Vaz, Luiz Paulo R.; Andersen, Johannes; Suntzeff, and Nicholas B.

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<dc:creator>Casey, Brian W.</dc:creator>
<dc:creator>Mathieu, Robert D.</dc:creator>
<dc:creator>Vaz, Luiz Paulo R.</dc:creator>
<dc:creator>Andersen, Johannes</dc:creator>
<dc:creator>Suntzeff, and Nicholas B.</dc:creator>
<dc:date>2007-12-18</dc:date>
<dc:description>We analyze new photometric data for the Herbig Be eclipsing binary TY CrA, which securely reveal the secondary eclipse, ~0.03 mag deep in y. From the light-curve solution and our previous spectroscopic data, absolute dimensions of the primary and secondary stars are derived. The masses are found to be M1 = 3.16 ± 0.02 M☉ and M2 = 1.64 ± 0.01 M☉, the radii are R1 = 1.80 ± 0.10 R☉ and R2 = 2.08 ± 0.14 R☉, the luminosities are L1 = 67 ± 12 L☉ and L2 = 2.4 ± 0.8 L☉, and the effective temperatures are T1 = 12,000 ± 500 K and T2 = 4900 ± 400 K. Here the uncertainties represent high-confidence limits, not standard deviations. The secondary star is a pre–main-sequence star located at the base of the Hayashi tracks. As such, it is the least evolved star with a dynamically measured mass. Given higher effective temperatures for the primary (e.g., 12,500 K), the solar-composition 1.64 M☉ evolutionary tracks of Swenson et al., Claret, and D'Antona &amp; Mazzitelli are all consistent with the properties of the TY CrA secondary and suggest an age of order 3 Myr. The radius and projected rotational velocity of the secondary star are consistent with synchronous rotation. The primary star is located near the zero-age main sequence, which, for solar compositions, is consistent with an age of 3 Myr. However, the primary star is not well represented by any of the 3.16 M☉ evolutionary models, which predict somewhat higher effective temperatures than observed.</dc:description>
<dc:identifier>https://zenodo.org/record/1059055</dc:identifier>
<dc:identifier>10.1086/300270</dc:identifier>
<dc:identifier>oai:zenodo.org:1059055</dc:identifier>
<dc:rights>info:eu-repo/semantics/openAccess</dc:rights>
<dc:title>The Pre-Main-Sequence Eclipsing Binary TY Coronae Australis: Precise Stellar Dimensions and Tests of Evolutionary Models</dc:title>
<dc:type>info:eu-repo/semantics/article</dc:type>
<dc:type>publication-article</dc:type>
</oai_dc:dc>

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