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Full-Text Articles in Physical Sciences and Mathematics
The M Supergiant High-Mass X-Ray Binary 4u 1954+31, Kenneth H. Hinkle, Thomas Lebzelter, Francis C. Fekel, Oscar Straniero, Richard Joyce, Lisa Prato, Nicole Karnath, Nolan Habel
The M Supergiant High-Mass X-Ray Binary 4u 1954+31, Kenneth H. Hinkle, Thomas Lebzelter, Francis C. Fekel, Oscar Straniero, Richard Joyce, Lisa Prato, Nicole Karnath, Nolan Habel
Information Systems and Engineering Management Research Publications
The X-ray binary 4U 1954+31 has been classified as a low-mass X-ray binary containing an M giant and a neutron star (NS). It has also been included in the rare class of X-ray symbiotic binaries. The Gaia parallax, infrared colors, spectral type, abundances, and orbital properties of the M star demonstrate that the cool star in this system is not a low-mass giant but a high-mass M supergiant. Thus, 4U 1954+31 is a high-mass X-ray binary (HMXB) containing a late-type supergiant. It is the only known binary system of this type. The mass of the M I is ${9}_{-2}^{+6}$ M⊙ …
Absolute Dimensions Of The Unevolved F-Type Eclipsing Binary Bt Vulpeculae, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Matthew W. Muterspaugh
Absolute Dimensions Of The Unevolved F-Type Eclipsing Binary Bt Vulpeculae, Guillermo Torres, Claud H. Sandberg Lacy, Francis C. Fekel, Matthew W. Muterspaugh
Information Systems and Engineering Management Research Publications
We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light-curve analysis lead to absolute masses and radii of ${M}_{1}=1.5439\pm 0.0098\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{1}=1.536\pm 0.018\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the primary, and ${M}_{2}=1.2196\pm 0.0080\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{2}=1.151\pm 0.029\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the secondary. The effective temperatures are 7270 ± 150 K and 6260 ± 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MESA Isochrones …