ABSTRACTwhich falls in the planetary-mass regime. This is the first discovery of a planetary companion orbiting a G-type giant star.

By using the high-dispersion spectra of 14 bright planet-harboring stars (along with 4 reference stars) observed with the new coudé echelle spectrograph at Okayama Astrophysical Observatory, we investigated the abundances of volatile elements (C, N, O, S, Zn; low condensation temperature T c ) in order to examine whether these show any significant difference compared to the abundances of other refractory elements (Si, Ti, V, Fe, Co, Ni; high T c ) which are known to be generally overabundant in those stars with planets, since a T c -dependence is expected if the cause of such a metal-richness is due to the accretion of solid planetesimals onto the host star. We found, however, that all elements we studied behave themselves quite similarly to Fe (i.e., [X/Fe]≃ 0) even for the case of volatile elements, which may suggest that the enhanced metallicity in those planet-bearing stars is not so much an acquired character (by accretion of rocky material) as rather primordial.

We present the results of our spectroscopic observations of eight detached eclipsing binaries (DEBs), selected from the Kepler Eclipsing Binary Catalog. Radial velocities (RVs) were calculated from high resolution spectra obtained with the HIDES spectrograph, attached to the 1.88-m telescope of the Okayama Astrophysical Observatory, and were used to characterize the targets in combination with the Kepler light curves. For each binary we obtained a full set of orbital and physical parameters, reaching precision below 3% in masses and radii for 5 pairs. By comparing our results with theoretical models, we assess the distance, age and evolutionary status of the researched objects. We also study eclipse timing variations of selected objects, and identify a new system with a γDor pulsator. Two systems are triples, and show lines coming from three components. In one case the motion of the outer star and the perturbation in the RVs of the inner binary are clearly visible and periodical, which allows us to directly calculate the mass of the third star, and inclination of the outer orbit. In the second case we only see a clear motion of the tertiary, and investigate two scenarios: that it is a linear trend coming from the orbital motion around the inner binary, and that it is caused by a planetary mass companion. When possible, we also compare our results with the literature, and conclude that only by combining photometry with RVs it is possible to obtain correct physical parameters of both components of a DEB.

Toward the aims of spectroscopically searching for planetary systems around stars, or detecting oscillations of solar-type stars for stellar seismology, we have started an experimental project of very precise determinations of stellar radial velocity variations based on the iodine-cell ($\mathrm{I}_{2}$ cell) technique at Okayama Astrophysical Observatory. We here report on the first preliminary results of test observations for two planet-harboring stars ($\upsilon $ And and $\tau $ Boo) based on data obtained by using the newly developed $\mathrm{I}_{2}$ cell and processed with a practical and quick analysis method. We confirmed that the internal statistical error can be as small as $5 \hbox{--} 6 \,\mathrm{m} \,\mathrm{s}^{-1}$ at best. Then, the resulting radial velocity solutions turned out to be in reasonable agreement with the well-established predicted variations over a time span of 4–5 days; the $O-C$ deviations indicate that a short-time-scale precision of $\sim 15\,\mathrm{m} \,\mathrm{s}^{-1}$ has been accomplished in a practical sense.

The cluster Zwicky 1615.8+3505 is considered to be a dynamically young poor cluster. To investigate the morphology and star-formation activity of galaxies under the environment of a dynamically young poor cluster, we have performed V , R, and I surface photometry, optical low-resolution spectroscopy, and 12 CO (J = 1 − 0) line observations for member galaxies. Our data show that more than 90% of the observed galaxies show regular morphologies and no star-1 formation activities, indicating that the environment does not affect these galaxy properties.Among sixteen galaxies observed, only NGC 6104 shows a significant star-formation activity, and shows a distorted morphology, indicating a tidal interaction. This galaxy contains double knots, and only one knot possesses Seyfert activity, though the sizes and luminosities are similar to each other; we also discuss this feature.Sports and Culture. † Research fellows of the Japan Society for the Promotion of Science. * The V -band magnitude and V − R and V − I colors within an isophotal ellipsoid of µ R = 23.5 mag arcsec −2 . The errors of measurements were estimated to be 0.02 mag for the magnitudes and colors, except for galaxies Nos. 12 and 14, the errors of which were estimated to be 0.1 mag. † The asymptotic total V -band magnitude and V − R and V − I colors. The errors of measurements were estimated to be 0.03 mag for the magnitudes and colors, except for galaxies Nos. 12 and 14, the errors of which were estimated to be 0.1 mag. ‡ The asymptotic total V -band magnitude and V − R and V − I colors correcting extinction and redshift effects. The errors of measurements were estimated to be 0.1 mag for the magnitudes and colors, except for galaxies Nos. 12 and 14, the errors of which were estimated to be 0.2 mag. 24