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Future high-contrast imaging spectroscopy with a large segmented telescope will be able to detect atmospheric molecules of Earth-like planets around G- or K-type main-sequence stars. Increasing the number of target planets will require a coronagraph with a small inner working angle (IWA), and wide spectral bandwidth is required if we enhance a variety of detectable atmospheric molecules. To satisfy these requirements, in this paper, we present a coronagraphic system that provides an IWA less than 1$λ_0 / D$ over a moderate wavelength band, where $λ_0$ is the design-center wavelength and $D$ denotes the full width of the rectangular aperture included in the telescope aperture. A performance simulation shows that the proposed system approximately achieves a contrast below $10^{-10}$ at 1$λ_0 / D$ over the wavelengths of 650--750nm. In addition, this system has a core throughput $\geq$ 10\% at input separation angles of $\sim$ 0.7--1.4$λ_0 / D$; to reduce telescope time, we need prior information on the target's orbit by other observational methods to a precision higher than the width of the field of view. For some types of aberration including tilt aberration, the proposed system has a sensitivity less than ever-proposed coronagraphs that have IWAs of approximately $1λ_0/D$. In future observations of Earth-like planets, the proposed coronagraphic system may serve as a supplementary coronagraphic system dedicated to achieving an extremely small IWA., Accepted for publication in the Astronomical Journal

We performed an X-ray diffraction experiment while palladium bulk absorbed and desorbed hydrogen to investigate the behavior of the crystalline lattice during the phase transition between the $\alpha$ phase and $\beta$ phase. Fast growth of $\beta$ phase was observed around x=0.1 and x=0.45 of PdH$_x$. In addition, slight compression of the lattice at high hydrogen concentration and increase in the lattice constant and the line width of the $\alpha$ phase after a cycle of absorption and desorption of hydrogen was observed. These behavior correlated with the change in the sample length, which may infer that the change in shape was related to the phase transition., Comment: 7 pages, 7 figures