4 research outputs found
Testing Multiband (G, GBP, GRP, B, V and TESS) Standard Bolometric Corrections by Recovering Luminosity and Radii of 341 Host Stars
Main-sequence bolometric corrections (BC) and a standard BC-Teff relation are
produced for TESS wavelengths using published physical parameters and light
ratios from SED models of 209 detached double-lined eclipsing binaries. This
and previous five-band (Johnson B, V, Gaia G, GBP, GRP) standard BC-Teff
relations are tested by recovering luminosity (L) of the most accurate 341
single host stars (281 MS, 40 subgiants, 19 giants and one PMS). The recovered
L of photometry is compared to L from published R and Teff. A very high
correlation ( = 0.9983) is achieved for this mixed sample. Error
histograms of recovered and calculated L show peaks at 2 and 4 per cent
respectively. The recovered L and the published Teff} were then used in to predict the standard R of the host stars. Comparison
between the predicted and published R of all luminosity classes are found
successful with a negligible offset associated with the giants and subgiants.
The peak of the predicted R errors is found at 2 per cent, which is equivalent
to the peak of the published R errors. Thus, a main-sequence BC-Teff relation
could be used in predicting both L and R of a single star at any luminosity
class, but this does not mean BC-Teff relations of all luminosity classes are
the same because luminosity information could be more constrained by star's
apparent magnitude than its BC since .Comment: 11 pages, 9 figures, a total of 6 tables, 5 online only table
Astronomical Site Selection for Turkey Using GIS Techniques
A site selection of potential observatory locations in Turkey have been
carried out by using Multi-Criteria Decision Analysis (MCDA) coupled with
Geographical Information Systems (GIS) and satellite imagery which in turn
reduced cost and time and increased the accuracy of the final outcome. The
layers of cloud cover, digital elevation model, artificial lights, precipitable
water vapor, aerosol optical thickness and wind speed were studied in the GIS
system. In conclusion of MCDA, the most suitable regions were found to be
located in a strip crossing from southwest to northeast including also a
diverted region in southeast of Turkey. These regions are thus our prime
candidate locations for future on-site testing. In addition to this major
outcome, this study has also been applied to locations of major observatories
sites. Since no goal is set for \textit{the best}, the results of this study is
limited with a list of positions. Therefore, the list has to be further
confirmed with on-site tests. A national funding has been awarded to produce a
prototype of an on-site test unit (to measure both astronomical and
meteorological parameters) which might be used in this list of locations.Comment: 17 pages, 10 figures, accepted by Experimental Astronom
Study of Eclipsing Binary and Multiple Systems in OB Associations. I. Orion OB1a-IM Monocerotis
All available photometric and spectroscopic observations were collected and used as the basis of a detailed analysis of the close binary IM Mon. The orbital period of the binary was refined to 1(d). 19024249 (0.00000014). The Roche equipotentials, fractional luminosities (in B, V, and Hp-bands) and fractional radii for the component stars in addition to the mass ratio, q, inclination, i, of the orbit, and the effective temperature, T-eff,, of the secondary cooler less massive component were obtained by the analysis of light curves. IM Mon is classified to be a detached binary system in contrast to the contact configuration estimations in the literature. The absolute parameters of IM Mon were derived by the simultaneous solutions of light and radial-velocity curves as M-1.2 = 5.50 (0.24) M-circle dot and 3.32 (0.16) M-circle dot, R1,2 = 3.15 (0.04) R-circle dot and 2.36 (0.03) R-circle dot, T-eff1.2 = 17500 (350) K and 14500 (550) K implying spectral types of B4 and B6.5 ZAMS stars for the primary and secondary components, respectively. The modelling of the high-resolution spectrum revealed the rotational velocities of the component stars as 17(rot1) = 147 (15) km s(-1) and V-rot2 = 90 (25)km s(-1). The photometric distance of 353 (59) pc was found to be more precise and reliable than the Hipparcos distance of 341 (85) pc. An evolutionary age of 11.5 (1.5) Myr was obtained for IM Mon. Kinematical and dynamical analyses support the membership of the young thin-disk population system IM Mon to the On OB1a association dynamically. Finally, we derived the distance, age, and metallicity information of On OB1a sub-group using information of the IM Mon parameters