- ID:
- ivo://CDS.VizieR/J/AJ/154/181
- Title:
- Radial velocities for the star HD 34445
- Short Name:
- J/AJ/154/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new precision radial velocity (RV) data set that reveals a multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists of 333 precision RV observations, 56 of which were previously published and 277 of which are new data from the Keck Observatory, Magellan at Las Campanas Observatory, and the Automated Planet Finder at Lick Observatory. These data indicate the presence of six planet candidates in Keplerian motion about the host star with periods of 1057, 215, 118, 49, 677, and 5700 days, and minimum masses of 0.63, 0.17, 0.1, 0.05, 0.12, and 0.38 MJ, respectively. The HD 34445 planetary system, with its high degree of multiplicity, its long orbital periods, and its induced stellar RV half-amplitudes in the range 2 m/s~<K~<5 m/s is fundamentally unlike either our own solar system (in which only Jupiter and Saturn induce significant reflex velocities for the Sun), or the Kepler multiple-transiting systems (which tend to have much more compact orbital configurations).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/708/1366
- Title:
- Radial velocities for 61 Vir
- Short Name:
- J/ApJ/708/1366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precision radial velocity data that reveal a multiple exoplanet system orbiting the bright nearby G5V star 61 Virginis. Our 4.6 years of combined Keck/HIRES and Anglo-Australian Telescope precision radial velocities indicate the hitherto unknown presence of at least three planets orbiting this well-studied star. These planets are all on low-eccentricity orbits with periods of 4.2, 38.0, and 124.0 days, and projected masses (Msini) of 5.1, 18.2, and 24.0M_{earth}_, respectively. Test integrations of systems consistent with the radial velocity data suggest that the configuration is dynamically stable.
- ID:
- ivo://CDS.VizieR/J/A+A/546/A61
- Title:
- Radial velocities for XHIP catalogue
- Short Name:
- J/A+A/546/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hundred-Thousand-Proper-Motion (HTPM) project will determine the proper motions of ~113500 stars using a ~23-year baseline. The proper motions will be based on space-based measurements exclusively, with the Hipparcos data, with epoch 1991.25, as first epoch and with the first intermediate-release Gaia astrometry, with epoch ~2014.5, as second epoch. The expected HTPM proper-motion standard errors are 30-190{mu}as/yr, depending on stellar magnitude. Depending on the astrometric characteristics of an object, in particular its distance and velocity, its radial velocity can have a significant impact on the determination of its proper motion. The impact of this perspective acceleration is largest for fast-moving, nearby stars. Our goal is to determine, for each star in the Hipparcos catalogue, the radial-velocity standard error that is required to guarantee a negligible contribution of perspective acceleration to the HTPM proper-motion precision.
- ID:
- ivo://CDS.VizieR/III/172
- Title:
- Radial Velocities from Objective Prism Plates
- Short Name:
- III/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate positions and radial velocities are determined from 32 objective-prism plates for two areas. Each field is observed twice with opposite dispersion, allowing adjustment of coordinates for spectra not at the plate centers. From the adjusted coordinates and plate overlap, positions are determined with average mean errors: 0.0135 s in RA and 0.177 arcsec in Dec for Area I (near the South Galactic Pole); 0.0315 s in RA, 0.144 arcsec in Dec for Area II (near the galactic plane). Observations were taken by J.D. MacConnell and G. Araya with a six degree prism on the Curtis Schmidt telescope at Cerro Tololo.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2261
- Title:
- Radial velocities in A2256
- Short Name:
- J/AJ/123/2261
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 236 new radial velocities of galaxies in the cluster A2256 measured with the WIYN Hydra Multi-Object Spectrograph. Combined with the previous work of Fabricant, Kent, & Kurtz (1989ApJ...336...77F), we have velocities for a total of 319 galaxies, of which 277 are cluster members. In addition to the new radial velocities, we present a 3x3 image mosaic in the R band of the central 19'x19' region of A2256, from which we obtained photometry for 861 galaxies. These data provide strong evidence for a merger event between two groups. In addition, we present evidence for the presence of a third group, on the outer reaches of the system, that is just now beginning to merge with the system.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/3453
- Title:
- Radial velocities in A1914
- Short Name:
- J/MNRAS/430/3453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the dynamical state of Abell 1914, a merging cluster hosting a radio halo, quite unusual for its structure. Our study considers spectroscopic data for 119 galaxies obtained with the Italian Telescopio Nazionale Galileo. We select 89 cluster members from spatial and velocity distributions. We also use photometry Canada-France-Hawaii Telescope archives. We compute the mean cluster redshift, <z>=0.168, and the velocity dispersion which shows a high value, {sigma}V=1210^+125^_-110_km/s. From the 2D analysis we find that Abell 1914 has a north-east (NE)-south-west (SW) elongated structure with two galaxy clumps, that mostly merge in the plane of the sky. Our best but very uncertain estimate of the velocity dispersion of the main system is {sigma}V, main ~1000km/s. We estimate a virial mass M_sys_=1.4-2.6x10^15^h^-1^_70_M_{sun}_ for the whole system. We study the merger through a simple two-body model and find that data are consistent with a bound, outgoing substructure observed just after the core crossing. By studying the 2D distribution of the red galaxies, photometrically selected, we show that Abell 1914 is contained in a rich large-scale structure, with two close companion galaxy systems, known to be at z~0.17. The system at SW supports the idea that the cluster is accreting groups from a filament aligned in the NE-SW direction, while that at NW suggests a second direction of the accretion (NW-SE). We conclude that Abell 1914 well fits among typical clusters with radio haloes. We argue that the unusual radio emission is connected to the complex cluster accretion and suggest that Abell 1914 resembles the well-known nearby merging cluster Abell 754 for its particular observed phenomenology.
- ID:
- ivo://CDS.VizieR/J/A+A/481/593
- Title:
- Radial velocities in A2163
- Short Name:
- J/A+A/481/593
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A2163 is among the richest and most distant Abell clusters, presenting outstanding properties in different wavelength domains. X-ray observations have revealed a distorted gas morphology and strong features have been detected in the temperature map, suggesting that merging processes are important in this cluster. However, the merging scenario is not yet well-defined. We have undertaken a complementary optical analysis, aiming to understand the dynamics of the system, to constrain the merging scenario and to test its effect on the properties of galaxies. We present a detailed optical analysis of A2163 based on new multicolor wide-field imaging and medium-to-high resolution spectroscopy of several hundred galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/449/461
- Title:
- Radial velocities in A2744
- Short Name:
- J/A+A/449/461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed dynamical analysis of the rich galaxy cluster A2744, containing a powerful diffuse radio-halo. Our analysis is based on redshift data for 102 galaxies, part of them recovered from unexplored spectra in the ESO archive. We combine galaxy velocity and position information to select the cluster members and determine global dynamical properties of the cluster. We use a variety of statistical tests to detect possible substructures. We find that A2744 appears as a well isolated peak in the redshift space at <z>=0.306, which includes 85 galaxies recognized as cluster members. We compute the line-of-sight (LOS) velocity dispersion of galaxies, sigma_V_=1767_-99_^121^km/s, which is significantly larger than what is expected in the case of a relaxed cluster with an observed X-ray temperature of 8 keV. We find evidence that this cluster is far from dynamical equilibrium, as shown by the non Gaussianity of the velocity distribution, the presence of a velocity gradient and a significant substructure. Our analysis shows the presence of two galaxy-clumps of different mean LOS velocities DeltaV~4000km/s. We detect a main, low-velocity clump with sigma_V_~1200-1300km/s and a secondary, high-velocity clump with sigma_V_=500-800km/s and located in the S-SW cluster region. We estimate a cluster mass within 1Mpc of 1.4-2.4M_{sun}_, depending on the model adopted to describe the cluster dynamics. Our results suggest a merging scenario of two clumps with a mass ratio of 3:1 and a LOS impact velocity of DeltaV_rf_~3000km/s, likely observed just after the core passage. The merging is occuring roughly in the NS direction with the axis close to the LOS. This scenario agrees with that proposed on the basis of recent Chandra results in its general lines although pointing out for a somewhat more advanced merging phase. Our conclusions support the view of the connection between extended radio emission and energetic merging phenomena in galaxy clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/147/69
- Title:
- Radial velocities in Be 44, Be 81, and NGC 6802
- Short Name:
- J/AJ/147/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocities for stars in the field of the open star clusters Berkeley 44, Berkeley 81, and NGC 6802 from spectra obtained using the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope. These clusters are of intermediate age (1-3Gyr), located within the solar Galactocentric radius, and have no previous radial velocity measurements. We find mean radial velocities of -9.6{+/-}3.0km/s, 48.1{+/-}2.0km/s, and 12.4{+/-}2.8km/s for Be 44, Be 81, and NGC 6802, respectively. We present an analysis of radial velocities of 134 open clusters of a wide range of ages using data obtained in this study and the literature. Assuming the system of clusters rotates about the Galactic center with a constant velocity, we find older clusters exhibit a slower rotation and larger line-of-sight (LOS) velocity dispersion than younger clusters. The gradual decrease in rotational velocity of the cluster system with age is accompanied by a smooth increase in LOS velocity dispersion, which we interpret as the effect of heating on the open cluster system over time.
- ID:
- ivo://CDS.VizieR/J/A+A/507/541
- Title:
- Radial velocities in cluster Blanco 1
- Short Name:
- J/A+A/507/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a part of our program on binaries in open clusters, we present a spectroscopic study of the bright stars of Blanco 1 aimed at detecting and characterizing spectroscopic binaries. Forty five stars previously mentioned as cluster candidates, plus another 24 stars in a wider region around the cluster were observed repeatedly during 6 years, with a spectral resolving power 13300. Radial velocities were measured by cross-correlations. We obtained a mean cluster velocity of 6.2+/-0.3km/s and determined kinematic membership. Eleven spectroscopic binaries were detected, and orbital solutions are presented for eight of them. Six binaries are confirmed to be members of the cluster. All of them are single-lined spectroscopic systems with periods in the range 1.9-1380 days. Considering all suspected binaries, the cluster binary frequency amounts to about 50%.
