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Observational Studies Of Early-Type Binary Stars: Mp Centauri, Dirk Terrell, Ulisse Munari, Tomaž Zwitter, George Wolf
Observational Studies Of Early-Type Binary Stars: Mp Centauri, Dirk Terrell, Ulisse Munari, Tomaž Zwitter, George Wolf
College of Natural and Applied Sciences
We present photometric and spectroscopic data on the early-type binary MP Centauri. The photometric data are analysed simultaneously with radial velocities to derive preliminary absolute dimensions for the binary components. Analysis of the spectra shows that the stars rotate synchronously and that the line of sight to the system crosses two kinematically sharp and well-separated interstellar reddening sources. It is shown that MP Cen consists of a B3 primary with M1 = 11.4 ± 0.4M⊙, R1 = 7.7 ± 0.1 R⊙ and a lobe-filling B6-B7 secondary with M2 = 4.4 ± 0.2 M⊙, R2 = 6.6 ± 0.1 R⊙.
Whole Earth Telescope Observations Of Bpm 37093: A Seismological Test Of Crystallization Theory In White Dwarfs, A. Kanaan, A. Nitta, D. E. Winget, S. O. Kepler, M. H. Montgomery, T. S. Metcalfe, H. Oliveira, L. Fraga, Michael D. Reed, For Complete List Of Authors, See Publisher's Website.
Whole Earth Telescope Observations Of Bpm 37093: A Seismological Test Of Crystallization Theory In White Dwarfs, A. Kanaan, A. Nitta, D. E. Winget, S. O. Kepler, M. H. Montgomery, T. S. Metcalfe, H. Oliveira, L. Fraga, Michael D. Reed, For Complete List Of Authors, See Publisher's Website.
College of Natural and Applied Sciences
BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which has sufficient mass (∼1.1 M⊙) to theoretically crystallize while still inside the ZZ Ceti instability strip (Teff ∼ 12000 K). As a consequence, this star represents our first opportunity to test crystallization theory directly. If the core is substantially crystallized, then the inner boundary for each pulsation mode will be located at the top of the solid core rather than at the center of the star, affecting mainly the average period spacing. This is distinct from the "mode trapping" caused by the stratified surface layers, which modifies the pulsation …