Yazar "Gokce, E. Yaz" seçeneğine göre listele

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    MAIN-SEQUENCE EFFECTIVE TEMPERATURES FROM A REVISED MASS-LUMINOSITY RELATION BASED ON ACCURATE PROPERTIES
    (Iop Publishing Ltd, 2015) Eker, Z.; Soydugan, Faruk; Soydugan, Esin; Bilir, S.; Gokce, E. Yaz; Steer, I.; Tuysuz, M.
    The mass-luminosity (M-L), mass-radius (M-R), and mass-effective temperature (M-T-eff) diagrams for a subset of galactic nearby main-sequence stars with masses and radii accurate to <= 3% and luminosities accurate to <= 30% (268 stars) has led to a putative discovery. Four distinct mass domains have been identified, which we have tentatively associated with low, intermediate, high, and very high mass main-sequence stars, but which nevertheless are clearly separated by three distinct break points at 1.05, 2.4, and 7 M-circle dot within the studied mass range of 0.38-32 M-circle dot. Further, a revised mass-luminosity relation (MLR) is found based on linear fits for each of the mass domains identified. The revised, mass-domain based MLRs, which are classical (L proportional to M-alpha), are shown to be preferable to a single linear, quadratic, or cubic equation representing an alternative MLR. Stellar radius evolution within the main sequence for stars with M > 1 M-circle dot is clearly evident on the M-R diagram, but it is not clear on the M-T-eff diagram based on published temperatures. Effective temperatures can be calculated directly using the well known Stephan-Boltzmann law by employing the accurately known values of M and R with the newly defined MLRs. With the calculated temperatures, stellar temperature evolution within the main sequence for stars with M>1 M-circle dot is clearly visible on the M-T-eff diagram. Our study asserts that it is now possible to compute the effective temperature of a main-sequence star with an accuracy of similar to 6%, as long as its observed radius error is adequately small (<1%) and its observed mass error is reasonably small (<6%).
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    Öğe
    The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way
    (Cambridge Univ Press, 2014) Eker, Z.; Bilir, S.; Soydugan, Faruk; Gokce, E. Yaz; Soydugan, Esin; Tuysuz, M.; Senyuz, T.
    The most accurate stellar astrophysical parameters were collected from the solutions of the light and the radial velocity curves of 257 detached double-lined eclipsing binaries in the Milky Way. The catalogue contains masses, radii, surface gravities, effective temperatures, luminosities, projected rotational velocities of the component stars, and the orbital parameters. The number of stars with accurate parameters increased 67% in comparison to the most recent similar collection by Torres, Andersen, & Gimenez (2010). Distributions of some basic parameters were investigated. The ranges of effective temperatures, masses, and radii are 2 750 < T-eff (K)< 43 000, 0.18 < M/M-circle dot < 33, and 0.2 < R/R-circle dot < 21.2, respectively. Being mostly located in one kpc in the Solar neighborhood, the present sample covers distances up to 4.6 kpc within the two local Galactic arms, Carina-Sagittarius and Orion Spur. The number of stars with both mass and radius measurements better than 1% uncertainty is 93, better than 3% uncertainty is 311, and better than 5% uncertainty is 388. It is estimated from the Roche lobe filling factors that 455 stars (88.5% of the sample) are spherical within 1% of uncertainty.