55752588
Searching for nuclear stellar discs in simulations of star cluster mergers
The nuclei of galaxies often host small stellar discs with scalelengths of a few tens of parsecs and luminosities up to 107 L�. To investigate the formation and properties of nuclear stellar discs (NSDs), we look for their presence in a set of N-body simulations studying the dissipationless merging of multiple star clusters in galactic nuclei. A few tens of star clusters with sizes and masses comparable to those of globular clusters observed in the Milky Way are accreted on to a pre-existing nuclear stellar component: either a massive super star cluster or a rapidly rotating, compact disc with a scalelength of a few parsecs, mimicking the variety of observed nuclear structures. Images and kinematic maps of the simulation time-steps are then built and analysed as if they were real and at the distance of the Virgo cluster. We use the Scorza–Bender method to search for the presence of disc structures via photometric decomposition. In one case, the merger remnant has all the observed photometric and kinematic properties of NSDs observed in real galaxies. This shows that current observations are consistent with most of the NSD mass being assembled from the migration and accretion of star clusters into the galactic centre. In the other simulation instead, we detect an elongated structure from the unsharp masked image, that does not develop the photometric or kinematic signature of an NSD. Thus, in the context of searches for a disc structure, the Scorza–Bender method is a robust and necessary tool.
55685116
A substellar component orbiting the F-star 30 Arietis B
Context. Most current radial velocity planet search programs have concentrated on stars of one solar mass. Our knowledge on the frequency of giant planets and brown dwarf companions to more massive stars is thus rather limited. In the case of solar-like stars, the frequency of short-period brown dwarf companions and very massive planets seems to be low. Aims. Here we present evidence for a substellar companion to 30 Ari B, an F-star of 1.16 ± 0.04 $M_\odot$ that is a member of a hierarchical triple system. Methods. The companion was detected by means of precise radial velocity measurements using the 2-m Alfred-Jensch telescope and its echelle spectrograph. An iodine absorption cell provided the wavelength reference for precise stellar radial velocity measurements. Results. We analyzed our radial velocity measurements and derived an orbit to the companion with period, P = 335.1 ± 2.5 days, eccentricity e = 0.289 ± 0.092, and mass function $f(m)$ = (6.1 ± 1.7)$\times$10 -7 $M_\odot$. Conclusions. We conclude that the radial velocity variations of 30 Ari B are due to a companion with m  sin  i of 9.88 ± 0.94 $M_{\mathrm{Jup}}$ that is either a massive planet or a brown dwarf. The object thus belongs to the rare class of massive planets and brown dwarfs orbiting main- sequence stars.
23095524
μ Eridani from MOST and from the ground: an orbit, the SPB component's fundamental parameters and the SPB frequencies
MOST time-series photometry of mu Eri, an SB1 eclipsing binary with a rapidly-rotating SPB primary, is reported and analyzed. The analysis yields a number of sinusoidal terms, mainly due to the intrinsic variation of the primary, and the eclipse light-curve. New radial-velocity observations are presented and used to compute parameters of a spectroscopic orbit. Frequency analysis of the radial-velocity residuals from the spectroscopic orbital solution fails to uncover periodic variations with amplitudes greater than 2 km/s. A Rossiter-McLaughlin anomaly is detected from observations covering ingress. 
From archival photometric indices and the revised Hipparcos parallax we derive the primary's effective temperature, surface gravity, bolometric correction, and the luminosity. An analysis of a high signal-to-noise spectrogram yields the effective temperature and surface gravity in good agreement with the photometric values. From the same spectrogram, we determine the abundance of He, C, N, O, Ne, Mg, Al, Si, P, S, Cl, and Fe. 
The eclipse light-curve is solved by means of EBOP. For a range of mass of the primary, a value of mean density, very nearly independent of assumed mass, is computed from the parameters of the system. Contrary to a recent report, this value is approximately equal to the mean density obtained from the star's effective temperature and luminosity. 
Despite limited frequency resolution of the MOST data, we were able to recover the closely-spaced SPB frequency quadruplet discovered from the ground in 2002-2004. The other two SPB terms seen from the ground were also recovered. Moreover, our analysis of the MOST data adds 15 low-amplitude SPB terms with frequencies ranging from 0.109 c/d to 2.786 c/d.
85540506
Oscillations in Procyon A First results from a multi-site campaign
Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state.
14319327
Confirmation of the Planet Hypothesis for the Long-period Radial Velocity Variations of Beta Geminorum
Aims. Our aim is to confirm the nature of the long period radial velocity measurements for β Gem first found by Hatzes & Cochran (1993). Methods. We present precise stellar radial velocity measurements for the K giant star β Gem spanning over 25 years. An examination of the Ca II K emission, spectral line shapes from high resolution data ($R = 210\,000$), and Hipparcos photometry was also made to discern the true nature of the long period radial velocity variations. Results. The radial velocity data show that the long period, low amplitude radial velocity variations found by Hatzes & Cochran (1993) are long-lived and coherent. Furthermore, the Ca II K emission, spectral line bisectors, and Hipparcos photometry show no significant variations of these quantities with the radial velocity period. An orbital solution assuming a stellar mass of 1.7 $M_\odot$ yields a period, $P = 589.6$ days, a minimum mass of 2.3 M Jupiter , and a semi-major axis, $a = 1.6$ AU. The orbit is nearly circular ($e = 0.02$). Conclusions. The data presented here confirm the planetary companion hypothesis suggested by Hatzes & Cochran (1993). β Gem is one of six intermediate mass stars known to host a sub-stellar companion and suggests that planet-formation around stars much more massive than the sun may common.
11578943
Planets of young stars: the TLS radial velocity survey
We report on the search for planets orbiting 46 nearby young stars performed at the State Observatory of Turingia (TLS) by means of a radial velocity survey. The aim of this program is to test the theories of formation/evolution of planetary systems. For 19(8) stars we can exclude planets with Msini > 1 MJ (5 MJ) and P < 10 days; we find 1 short period binary and 5 stars with long period RV-trend. One good young exo-planet candidate is presented.
38257834
Steady state entanglement in the mechanical vibrations of two dielectric membranes.
We consider two dielectric membranes suspended inside a Fabry-Perot cavity, which are cooled to a steady state via a drive by suitable classical lasers. We show that the vibrations of the membranes can be entangled in this steady state. They thus form two mechanical, macroscopic degrees of freedom that share steady state entanglement.
119228024
Measurement of the pn ---> dK+ K- total cross section close to threshold
Measurements of the pd → p sp dK + K - reaction, where p sp is a spectator proton, have been undertaken at the Cooler Synchrotron COSY-Jiilich by detecting a fast deuteron in coincidence with a K + K - pair in the ANKE facility. Although the proton beam energy was fixed, the moving target neutron allowed values of the nonresonant quasifree pn → dK + K - total cross section to be deduced up to an excess energy e ≈ 100 MeV. Evidence is found for the effects of K - d and KK final state interactions. The comparison of these data with those of pp → ppK + K - and pp → dK + K 0 shows that all the total cross sections are very similar in magnitude.
117375800
Study of Medium Modifications with the New Spectrometer ANKE at COSY-Juelich
126088099
Measurement of the phi-meson nuclear transparency in proton-nucleus collisions