Fundamental properties of solar-like oscillating stars from frequencies of minimum Δν\Delta \nu : II. Model computations for different chemical compositions and mass

The large separations between the oscillation frequencies of solar-like stars are measures of stellar mean density. The separations have been thought to be mostly constant in the observed range of frequencies. However, detailed investigation shows that they are not constant, and their variations are not random but have very strong diagnostic potential for our understanding of stellar structure and evolution. In this regard, frequencies of the minimum large separation are very useful tools. From these frequencies, in addition to the large separation and frequency of maximum amplitude, Y\i ld\i z et al. recently have developed new methods to find almost all the fundamental stellar properties. In the present study, we aim to find metallicity and helium abundances from the frequencies, and generalize the relations given by Y\i ld\i z et al. for a wider stellar mass range and arbitrary metallicity ($Z$) and helium abundance ($Y$). We show that the effect of metallicity is { significant} for most of the fundamental parameters. For stellar mass, for example, the expression must be multiplied by (Z/Z_{\sun})^{0.12}. For arbitrary helium abundance, M \propto (Y/Y_{\sun})^{0.25} . Methods for determination of $Z$ and $Y$ from pure asteroseismic quantities are based on amplitudes (differences between maximum and minimum values of \Dnu) in the oscillatory component in the spacing of oscillation frequencies. Additionally, we demonstrate that the difference between the first maximum and the second minimum is very sensitive to $Z$. It also depends on $\nu_{\rm min1}/\nu_{\rm max}$ and small separation between the frequencies. Such a dependence leads us to develop a method to find $Z$ (and $Y$) from oscillation frequencies. The maximum difference between the estimated and model $Z$ values is about 14 per cent. It is 10 per cent for $Y$.Comment: 8 pages, 13 figures; published in MNRAS (2015

Comparison of Gaia and asteroseismic distances

Asteroseismology provides fundamental properties (mass, radius and effective temperature) of solar-like oscillating stars using so-called scaling relations. These properties allow the computation of the asteroseismic distance of stars. We compare the asteroseismic distances with the recently released Gaia distances for 74 stars studied in Y{\i}ld{\i}z et al. There is a very good agreement between these two distances; for 64 of these stars, the difference is less than 10 per cent. However, a systematic difference is seen if we use the effective temperature obtained by spectroscopic methods; the Gaia distances are about 5 per cent greater than the asteroseismic distances.Comment: 4 pages, 4 figures, accepted by MNRA

On the structure and evolution of planets and their host stars −- effects of various heating mechanisms on the size of giant gas planets

It is already stated in the previous studies that the radius of the giant planets is affected by stellar irradiation. The confirmed relation between radius and incident flux depends on planetary mass intervals. In this study, we show that there is a single relation between radius and irradiated energy per gram per second ($l_-$), for all mass intervals. There is an extra increase in radius of planets if $l_-$ is higher than 1100 times energy received by the Earth ($l_\oplus$). This is likely due to dissociation of molecules. The tidal interaction as a heating mechanism is also considered and found that its maximum effect on the inflation of planets is about 15 per cent. We also compute age and heavy element abundances from the properties of host stars, given in the TEPCat catalogue (Southworth 2011). The metallicity given in the literature is as [Fe/H]. However, the most abundant element is oxygen, and there is a reverse relation between the observed abundances [Fe/H] and [O/Fe]. Therefore, we first compute [O/H] from [Fe/H] by using observed abundances, and then find heavy element abundance from [O/H]. We also develop a new method for age determination. Using the ages we find, we analyse variation of both radius and mass of the planets with respect to time, and estimate the initial mass of the planets from the relation we derive for the first time. According to our results, the highly irradiated gas giants lose 5 per cent of their mass in every 1 Gyr.Comment: 15 pages, 13 figures, 3 tables. Accepted by MNRA

Crystal structure of rac-3-hydroxy-2-(p-tolyl)-2,3,3a,4,7,7a-hexahydro-1H-4,7-methanoisoindol-1-one

In the title compound, C16H17NO2, the cyclohexene ring adopts a boat conformation, and the five-membered rings have envelope conformations with the bridging atom as the flap. Their mean planes are oriented at a dihedral angle of 86.51 (7)°. The molecular structure is stabilized by a short intramolecular C - H⋯O contact. In the crystal, molecules are linked by O - H⋯O hydrogen bonds forming chains propagating along [100]. The chains are linked by C - H⋯π interactions, forming slabs parallel to (001)

Meristem culture for clonal micropropagation of grapevines

Experiments were carried out to determine the effects of MS medium concentrations (4/4 MS, 3/4 MS, 2/4 MS) combined with GA3 at 0.0, 0.1 and 0.5 mg/l, and vitamin formulations (MS, Morel, thiamine-inositol) on success of meristem culture and of 15 auxin (IBA) x cytokinin (BAP) combinations on shoot and root formation for clonal rnicropropagation of the wine grape cv. Kalecik Karasi and the rootstock cv. 41 B M.G. Best results were obtained from standard MS mineral composition and vitamin formulation combined with 2.5 mg/l BAP and 0.5 mg/l GA3 for primary meristem cultures of both genotypes; 0.0 mg/l IBA x 1.0 mg/l BAP for shoot subculture and 1.0 mg/l IBA x 0.0 mg/l BAP for root subculture of Kalecik Karasi; 0.0 mg/l IBA x 1.0 mg/l BAP for shoot subculture and 5.0 mg/l IBA x 0.0 mg/l BAP for root subculture of 41 B, considering shoot, explant, root, callus and particularly entire plant formation in the cultures of both stages

An anatomical study of the origins of the medial circumflex femoral artery in the Turkish population

The medial circumflex femoral artery (MCFA) usually branches from the deep femoral artery (DFA). It may also branch from the femoral artery (FA). In this study 100 inguinal regions of 50 cadavers were investigated. In 79 extremities (79%) MCFA branched from DFA, while in 15 (15%) it branched from FA. In four extremities (4%) MCFA was found to be double; in each case one of MCFAs branched from FA and the other from DFA. In one of these four cases the lateral circumflex femoral artery (LCFA) was also double. In one case we found a common trunk of DFA and MCFA and in another case a common trunk of MCFA, DFA and LCFA. Clinicians must be familiar with the variations of this clinically important artery to improve their success in the diagnosis and treatment of pathologies in the region

Uptake of aniline and nitrobenzene from aqueous solution by organo-zeolite

Adsorption mechanisms of toxic non-ionic organic contaminants (NOCs), aniline and nitrobenzene, with natural-zeolite andorgano-zeolite (OZ) were investigated in both batch and continuous systems. In batch tests, the adsorption capacity ofaniline and nitrobenzene onto natural zeolite surface is very low or almost nil but becomes significant upon modifying thezeolite surface by hexadecyltrimethylammonium (HDTMA). A partitioning mechanism is proposed to be responsible for the adsorption of NOCs onto OZ. The effectiveness of the partitioning mechanism is directly connected with hydrophobicproperties of the NOCs. The column tests were carried out as an indicator for continuous system. The breakthrough curveswere constructed for OZ/NOC system and the adsorption capacity of NOCs onto OZ under the present conditions weredetermined as 2.36 and 3.25 mg per gram of OZ, for aniline and nitrobenzene, respectively. A schematic model is proposedto account for the adsorption of NOCs onto OZ