ヒシンシュウテキ カクサン カイセキ ニ ムケタ アラタナ ケンシュツホウ ノ カイハツ

京都大学0048新制・課程博士博士(工学)甲第13791号工博第2895号新制||工||1427(附属図書館)26007UT51-2008-C707京都大学大学院工学研究科合成・生物化学専攻(主査)教授 青山 安宏, 教授 森 泰生, 教授 濵地 格学位規則第4条第1項該当Doctor of EngineeringKyoto UniversityDFA

Analytic Description of the Rossiter-McLaughlin Effect for Transiting Exoplanets: Cross-Correlation Method and Comparison with Simulated Data

We obtain analytical expressions for the velocity anomaly due to the Rossiter- McLaughlin effect, for the case when the anomalous radial velocity is obtained by cross-correlation with a stellar template spectrum. In the limit of vanishing width of the stellar absorption lines, our result reduces to the formula derived by Ohta et al. (2005), which is based on the first moment of distorted stellar lines. Our new formula contains a term dependent on the stellar linewidth, which becomes important when rotational line broadening is appreciable. We generate mock transit spectra for four existing exoplanetary systems (HD17156, TrES-2, TrES- 4, and HD209458) following the procedure of Winn et al. (2005), and find that the new formula is in better agreement with the velocity anomaly extracted from the mock data. Thus, our result provides a more reliable analytical description of the velocity anomaly due to the Rossiter-McLaughlin effect, and explains the previously observed dependence of the velocity anomaly on the stellar rotation velocity.Comment: 31 pages, 9 figures, Astrophysical Journal in pres

Chromatographic formation of a triadic band of lithium in hydrated LTA zeolite: An investigation on lithium isotope separation effects by ion exchange

published online 12 April 2017Lithium concentrations [Li] and isotopic ratios [Li-7]/[Li-6] were measured for effluent fractions from a biphasic zeolite column. The biphasic state was ascribed to a mixture of hydrated Linde Type A (LTA) zeolites, [Li-0.008(NH4)(0.92)]A and [Li-0.33(NH4)(0.67)]A, which were formed by Li ion exchange from hydrated ammonium in the form (NH4)(12)[Al12Si12O48]center dot nH(2)O (NH(4)A). The biphasic Li band of the column was displaced by ion exchange with a solution of NH4NO3. A constant [Li] with a much lower level than the concentration of NHt(4)(_)(+) in the displacer (NH4NO3) was observed for the effluent from a short column. This constant lower level of [Li] was attributable to the biphasic state. On this [Li] plateau of the effluent, the level of [Li-7] shifted higher than the original isotopic composition of the Li feed, whereas Li-6 was concentrated on the biphasic zeolite solid. The accumulation of Li-6 in the zeolite proceeded by a mechanism of differential elution of Li-7 from the biphasic zeolite. For the long column experiment, a significant enrichment of Li-6 in the zeolite was observed, whereby a triadic band of Li was probably formed in the column. Two monophasic and a biphasic state were assigned. The biphasic band was deemed to push the monophasic bands forward, thereby enriching the monophasic bands with Li-7, while Li-6 accumulated at the end of the biphasic band. The trio structure of the Li band and isotopic discrimination in the band were analyzed. (C) 2017 Elsevier Inc. All rights reserved.ArticleMICROPOROUS AND MESOPOROUS MATERIALS. 248:115-121 (2017)journal articl

Improved modeling of the Rossiter-McLaughlin effect for transiting exoplanets

We present an improved formula for the anomalous radial velocity of the star during planetary transits due to the Rossiter-McLaughlin (RM) effect. The improvement comes from a more realistic description of the stellar absorption line profiles, taking into account stellar rotation, macroturbulence, thermal broadening, pressure broadening, and instrumental broadening. Although the formula is derived for the case in which radial velocities are measured by cross-correlation, we show through numerical simulations that the formula accurately describes the cases where the radial velocities are measured with the iodine absorption-cell technique. The formula relies on prior knowledge of the parameters describing macroturbulence, instrumental broadening, and other broadening mechanisms, but even 30% errors in those parameters do not significantly change the results in typical circumstances. We show that the new analytic formula agrees with previous ones that had been computed on a case-by-case basis via numerical simulations. Finally, as one application of the new formula, we reassess the impact of the differential rotation on the RM velocity anomaly. We show that differential rotation of a rapidly rotating star may have a significant impact on future RM observations.United States. National Aeronautics and Space Administration (Origins program grant NNX11AG85G

Measurement of the Rossiter--McLaughlin Effect in the Transiting Exoplanetary System TrES-1

We report a measurement of the Rossiter--McLaughlin effect in the transiting extrasolar planetary system TrES-1, via simultaneous spectroscopic and photometric observations with the Subaru and MAGNUM telescopes. By modeling the radial velocity anomaly that was observed during a transit, we determine the sky-projected angle between the stellar spin axis and the planetary orbital axis to be $\lambda = 30 \pm 21$ [deg]. This is the third case for which $\lambda$ has been measured in a transiting exoplanetary system, and the first demonstration that such measurements are possible for relatively faint host stars ($V \sim 12$, as compared to $V \sim 8$ for the other systems). We also derive a time of mid-transit, constraints on the eccentricity of the TrES-1b orbit ($e = 0.048 \pm 0.025$), and upper limits on the mass of the Trojan companions ($\lesssim$14 $M_{\oplus}$) at the 3$\sigma$ level.Comment: 8 pages, 5 figures, 2 tables. Published in PASJ. Corrected typo

Mechanical anisotropy of deep ice core samples by uniaxial compression tests (scientific paper)

Mechanical anisotropy of ice core samples has been observed in various uniaxial compression tests. The c-axis orientation distribution is the primary influence on the mechanical behavior of ice cores. A strong single-maximum fabric pattern is observed in the deep parts of the ice sheet. In this region, polycrystalline ice is very hard along the vertical axis; however, it easily shears along the horizontal plane. Thus, by acquiring the distribution of c-axis orientations throughout the ice sheet, the mechanical anisotropy of ice sheet flow behavior can be understood. Analysis of fabric measurements on the Dye 3, GRIP, and Dome F ice cores suggests that the c-axis orientation distribution depends primarily on vertical strain. Therefore, if the ice thickness at some point in the ice sheet is known, it should be possible to predict the distribution of c-axis orientations at that depth. Uniaxial compression tests were carried out along various directions of the Dye 3, GRIP, and Dome F ice cores. A contour map of mechanical anisotropy was then made to relate the compression direction to the vertical strain. This clarified the flow enhancement factor in every compression direction at a given vertical strain

Further Observations of the Tilted Planet XO-3: A New Determination of Spin-Orbit Misalignment, and Limits on Differential Rotation

Abstract: We report on observations of the Rossiter-McLaughlin (RM) effect for the XO-3 exoplanetary system. The RM effect for the system was previously measured by two different groups, but their results were statistically inconsistent. To obtain a decisive result we observed two full transits of XO-3b with the Subaru 8.2-m telescope. By modeling these data with a new and more accurate analytic formula for the RM effect, we find the projected spin-orbit angle to be λ=37.3 deg ± 3.0 deg, in good agreement with the previous finding by Winn et al. (2009). In addition, an offset of ~22 m/s[superscript -1] was observed between the two transit datasets. This offset could be a signal of a third body in the XO-3 system, a possibility that should be checked with future observations. We also attempt to search for a possible signature of the stellar differential rotation in the RM data for the first time, and put weak upper limits on the differential rotation parameters.United States. National Aeronautics and Space Administration (NNX11AG85G