Oscillations in the G-type Giants

The precise radial-velocity measurements of 4 G-type giants, 11Com, $\zeta$ Hya, $\epsilon$ Tau, and $\eta$ Her were carried out. The short-term variations with amplitudes, 1-7m/s and periods, 3-10 hours were detected. A period analysis shows that the individual power distribution is in a Gaussian shape and their peak frequencies ($\nu_{max}$) are in a good agreement with the prediction by the scaling law. With using a pre-whitening procedure, significant frequency peaks more than 3 $\sigma$ are extracted for these giants. From these peaks, we determined the large frequency separation by constructing highest peak distribution of collapsed power spectrum, which is also in good agreement with what the scaling law for the large separation predicts. Echelle diagrams of oscillation frequency were created based on the extracted large separations, which is very useful to clarify the properties of oscillation modes. In these echelle diagrams, odd-even mode sequences are clearly seen. Therefore, it is certain that in these G-type giants, non-radial modes are detected in addition to radial mode. As a consequence, these properties of oscillation modes are shown to follow what Dzymbowski et al.(2001) and Dupret et al.(2009) theoretically predicted. Damping times for these giants were estimated with the same method as that developed by Stello et al.(2004). The relation of Q value (ratio of damping time to period) to the period was discussed by adding the data of the other stars ranging from dwarfs to giants.Comment: 28 pages, 16 figures, accepted for publication in PASJ 62, No.4, 201

Cluster diffusion on two-dimensional surface with immobile impurities

We study diffusion of a two-dimensional cluster on a two-dimensional surface with immobile impurities. We perform a kinetic Monte Carlo simulation using a simple square lattice model. In our model, not only atoms forming an edge of two-dimensional cluster but also atoms in the cluster, which is neighboring impurities in the cluster, are able to evaporate. The cluster diffusion coefficient in the system with a high impurity concentration is larger than that with no impurities. © 2013 Elsevier B.V. All rights reserved

The effect of free-stream turbulence on heat transfer from a flat plate

Turbulence was generated by using screens, and the turbulence percentage was measured by a hot-wire anemometer both in the boundary layer and the free stream. The local heat-transfer coefficient was measured at 12 locations along the plate for the cases of various turbulence levels. The transition Reynolds number from laminar to turbulent flow decreases as the main-stream turbulence level increases. In the range of laminar heat transfer the effect of turbulence in the main flow was not great, but in the range of turbulent heat transfer the heat-transfer coefficient increases according to the increase of turbulence

Ethane-1,2-diyl bis­(benzene­dithio­ate)

In the crystal structure, the title compound, C16H14S4, is located on an inversion center and exhibits a gauche+–trans–gauche− conformation in the S—CH2—CH2—S bond sequence. The S—C=S plane makes a dihedral angle of 30.63 (17)° with the phenyl ring. An inter­molecular C—H⋯π inter­action is observed

Substellar Companions to Seven Evolved Intermediate-Mass Stars

We report the detections of substellar companions orbiting around seven evolved intermediate-mass stars from precise Doppler measurements at Okayama Astrophysical Observatory. o UMa (G4 II-III) is a giant with a mass of 3.1 M_sun and hosts a planet with minimum mass of m_2sini=4.1 M_J in an orbit with a period P=1630 d and an eccentricity e=0.13. This is the first planet candidate (< 13 M_J) ever discovered around stars more massive than 3 M_sun. o CrB (K0 III) is a 2.1 M_sun giant and has a planet of m_2sini=1.5 M_J in a 187.8 d orbit with e=0.19. This is one of the least massive planets ever discovered around ~2 M_sun stars. HD 5608 (K0 IV) is an 1.6 M_sun subgiant hosting a planet of m_2sini=1.4 M_J in a 793 d orbit with e=0.19. The star also exhibits a linear velocity trend suggesting the existence of an outer, more massive companion. 75 Cet (G3 III:) is a 2.5 M_sun giant hosting a planet of m_2sini=3.0 M_J in a 692 d orbit with e=0.12. The star also shows possible additional periodicity of about 200 d and 1880 d with velocity amplitude of ~7--10 m/s, although these are not significant at this stage. nu Oph (K0 III) is a 3.0 M_sun giant and has two brown-dwarf companions of m_2sini= 24 M_J and 27 M_J, in orbits with P=530.3 d and 3190 d, and e=0.126 and 0.17, respectively, which were independently announced by Quirrenbach et al. (2011). The ratio of the periods is close to 1:6, suggesting that the companions are in mean motion resonance. We also independently confirmed planets around k CrB (K0 III-IV) and HD 210702 (K1 IV), which had been announced by Johnson et al. (2008) and Johnson et al. (2007a), respectively. All of the orbital parameters we obtained are consistent with the previous results.Comment: 21 pages, 14 figures, accepted for publication in PAS

Three-dimensional lattice structure formed in a binary system with DNA nanoparticles

Keeping the formation of lattice structures by nanoparticles covered with DNA in mind, we carry out Brownian dynamics simulations and study three-dimensional lattice structures formed by two species of particles. In our previous study [H. Katsuno, Y. Maegawa, and M. Sato, J. Phys. Soc. Jpn. 85, 074605 (2016)], we used the Lennard-Jones potential and studied two-dimensional structures formed in a binary system. When the interaction length between the different species, σ′, is shorter than that between the same species, σ, the lattice structure changes with the ratio σ′/σ. In this paper, we use the same potential and study the formation of three-dimensional structures. With decreasing ratio σ′/σ, the mixture of the face-centered-cubic (fcc) structure and hexagonal-close-packed (hcp) structure is changed to the bodycentered-cubic (bcc) structure and the NaCl structure. © 2017 The Physical Society of Japan.Embargo Period 12 month

Effect of difference in interaction strength on two-dimensional lattice structure in a binary system with DNA nanoparticles

Keeping two-dimensional lattice structures formed by nanoparticles covered with DNA in mind, we carry out Brownian dynamics simulations to study the effect of interaction strength on a two-dimensional lattice structure formed in a binary system. In our previous study [H. Katsuno, Y. Maegawa, and M. Sato, J. Phys. Soc. Jpn. 85, 074605 (2016)], we carried out simulations using the Lennard-Jones potential, in which the difference in interaction length was taken into account. When the interaction length between different species, σ$, is smaller than that between the same species, σ, various lattice structures were formed with changing the ratio σ$/σ. In this paper, taking the difference in the interaction strength into account, we study the effect of the difference in interaction strength on the two-dimensional lattice structure. © 2017 The Japan Society of Applied PhysicsEmbargo Period 12 month