- ID:
- ivo://CDS.VizieR/J/AJ/149/53
- Title:
- Radial velocities of 12 Milky Way globular clusters
- Short Name:
- J/AJ/149/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present central velocity dispersions, masses, mass-to-light ratios (M/Ls), and rotation strengths for 25 Galactic globular clusters (GCs). We derive radial velocities of 1951 stars in 12 GCs from single order spectra taken with Hectochelle on the MMT telescope. To this sample we add an analysis of available archival data of individual stars. For the full set of data we fit King models to derive consistent dynamical parameters for the clusters. We find good agreement between single-mass King models and the observed radial dispersion profiles. The large, uniform sample of dynamical masses we derive enables us to examine trends of M/L with cluster mass and metallicity. The overall values of M/L and the trends with mass and metallicity are consistent with existing measurements from a large sample of M31 clusters. This includes a clear trend of increasing M/L with cluster mass and lower than expected M/Ls for the metal-rich clusters. We find no clear trend of increasing rotation with increasing cluster metallicity suggested in previous work.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/813/89
- Title:
- Radial velocities of Milky Way inner halo stars
- Short Name:
- J/ApJ/813/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the three components of velocity dispersion, {sigma}_R_, {sigma}_{theta}_, {sigma}_{phi}_, for stars within 6<R<30kpc of the Milky Way using a new radial velocity sample from the MMT telescope. We combine our measurements with previously published data so that we can more finely sample the stellar halo. We use a maximum likelihood statistical method for estimating mean velocities, dispersions, and covariances assuming only that velocities are normally distributed. The alignment of the velocity ellipsoid is consistent with a spherically symmetric gravitational potential. From the spherical Jeans equation, the mass of the Milky Way is M(R<=12kpc)=1.3x10^11^M_{sun}_ with an uncertainty of 40%. We also find a region of discontinuity, 15<~R<~25kpc, where the estimated velocity dispersions and anisotropies diverge from their anticipated values, confirming the break observed by others. We argue that this break in anisotropy is physically explained by coherent stellar velocity structure in the halo, such as the Sgr stream. To significantly improve our understanding of halo kinematics will require combining radial velocities with future Gaia proper motions.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/97
- Title:
- Radial velocities of multi-planet systems
- Short Name:
- J/ApJS/182/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extrasolar multiple-planet systems provide valuable opportunities for testing theories of planet formation and evolution. The architectures of the known multiple-planet systems demonstrate a fascinating level of diversity, which motivates the search for additional examples of such systems in order to better constrain their formation and dynamical histories. Here we describe a comprehensive investigation of 22 planetary systems in an effort to answer three questions: (1) are there additional planets? (2) where could additional planets reside in stable orbits? and (3) what limits can these observations place on such objects? We find no evidence for additional bodies in any of these systems; indeed, these new data do not support three previously announced planets (HD 20367 b: Udry et al., 2003ASPCC..294...17U; HD 74156 d: Bean et al., 2008ApJ...672.1202B; and 47 UMa c: Fischer et al., 2002ApJ...564.1028F). The dynamical simulations show that nearly all of the 22 systems have large regions in which additional planets could exist in stable orbits. The detection-limit computations indicate that this study is sensitive to close-in Neptune-mass planets for most of the systems targeted. We conclude with a discussion on the implications of these nondetections.
- ID:
- ivo://CDS.VizieR/J/A+A/521/A12
- Title:
- Radial velocities of nearby late-type stars
- Short Name:
- J/A+A/521/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nearby late-type stars are excellent targets for seeking young objects in stellar associations and moving groups. The origin of these structures is still misunderstood, and lists of moving group members often change with time and also from author to author. Most members of these groups have been identified by means of kinematic criteria, leading to an important contamination of previous lists by old field stars. We attempt to identify unambiguous moving group members among a sample of nearby-late type stars by studying their kinematics, lithium abundance, chromospheric activity, and other age-related properties.
- ID:
- ivo://CDS.VizieR/III/191
- Title:
- Radial Velocities of Nearby Stars
- Short Name:
- III/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue contains radial 1365 individual measurements of radial velocities of 200 dwarf stars within 25 parsecs from the Sun, mostly of spectral types K and M. They were measured in 1986-1985 with correlation spectrometer. The typical accuracy is 0.3-0.8km/s. The average parameters of correlation dip (equivalent width and FWHM) are also given and may be used to estimate axial rotation and metallicity.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A31
- Title:
- Radial velocities of nearby stars
- Short Name:
- J/A+A/626/A31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed stars with variable radial velocities to determine their spectroscopic orbits. Velocities of 132 targets taken over a time span reaching 30 years are presented. They were measured with the correlation radial velocity spectrometers (1913 velocities) and the new VUES echelle spectrograph (632 velocities), with typical accuracy of 0.5 and 0.2km/s, respectively. We derived spectroscopic orbits of 57 stars (including 53 first-time orbits), mostly nearby dwarfs of spectral types K and M. Their periods range from 2.2 days to 14 years, some of those are Hipparcos astrometric binaries. Comments on individual objects are provided. Many stars belong to hierarchical systems containing three or more components, including 20 new hierarchies resulting from this project. The preliminary orbit of the young star HIP 47110B has a large eccentricity e=0.47 despite short period of 4.4d; it could be still circularizing. Our results enrich the data on nearby stars and contribute toa better definition of the multiplicity statistics.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/46
- Title:
- Radial velocities of 3 Neptune-mass planet hosts
- Short Name:
- J/ApJ/830/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of three modestly irradiated, roughly Neptune-mass planets orbiting three nearby Solar-type stars. HD42618b has a minimum mass of 15.4+/-2.4 M_{Earth}_, a semimajor axis of 0.55au, an equilibrium temperature of 337K, and is the first planet discovered to orbit the solar analogue host star, HD42618. We also discover new planets orbiting the known exoplanet host stars HD164922 and HD143761 ({rho} CrB). The new planet orbiting HD164922 has a minimum mass of 12.9+/-1.6 M_{Earth}_ and orbits interior to the previously known Jovian mass planet orbiting at 2.1au. HD164922c has a semimajor axis of 0.34au and an equilibrium temperature of 418K. HD143761c orbits with a semimajor axis of 0.44au, has a minimum mass of 25+/-2 M_{Earth}_, and is the warmest of the three new planets with an equilibrium temperature of 445K. It orbits exterior to the previously known warm Jupiter in the system. A transit search using space-based CoRoT data and ground-based photometry from the Automated Photometric Telescopes (APTs) at Fairborn Observatory failed to detect any transits, but the precise, high-cadence APT photometry helped to disentangle planetary-reflex motion from stellar activity. These planets were discovered as part of an ongoing radial velocity survey of bright, nearby, chromospherically inactive stars using the Automated Planet Finder (APF) telescope at Lick Observatory. The high-cadence APF data combined with nearly two decades of radial velocity data from Keck Observatory and gives unprecedented sensitivity to both short-period low-mass, and long-period intermediate-mass planets.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A63
- Title:
- Radial velocities of 7 new HARPS planetary systems
- Short Name:
- J/A+A/527/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We are conducting a planet search survey with HARPS since seven years. The volume-limited stellar sample includes all F2 to M0 main-sequence stars within 57.5pc, where extrasolar planetary signatures are systematically searched for with the radial-velocity technics. In this paper, we report the discovery of new substellar companions of seven main-sequence stars and one giant star, detected through multiple Doppler measurements with the instrument HARPS installed on the ESO 3.6m telescope, La Silla, Chile.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A22
- Title:
- Radial velocities of 3 new hot Jupiters
- Short Name:
- J/A+A/563/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision radial-velocity measurements of three solar-type stars: HD 13908, HD 159243, and HIP 91258. The observations were made with the SOPHIE spectrograph at the 1.93m telescope of the Observatoire de Haute-Provence (France). They show that these three bright stars host exoplanetary systems composed of at least two companions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/3376
- Title:
- Radial velocities of NGC 6822 carbon stars
- Short Name:
- J/MNRAS/462/3376
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using spectra taken with the AAOmega spectrograph, we measure the radial velocities of over 100 stars, many of which are intermediate age carbon stars, in the direction of the dwarf irregular galaxy NGC 6822. Kinematic analysis suggests that the carbon stars in the sample are associated with NGC 6822, and estimates of its radial velocity and galactic rotation are made from a star-by-star analysis of its carbon star population. We calculate a heliocentric radial velocity for NGC 6822 of -51+/-3km/s and show that the population rotates with a mean rotation speed of 11.2+/-2.1km/s at a mean distance of 1.1kpc from the galactic centre, about a rotation axis with a position angle of 26{deg}+/-13{deg}, as projected on the sky. This is close to the rotation axis of the HI gas disc and suggests that NGC 6822 is not a polar ring galaxy, but is dynamically closer to a late-type galaxy. However, the rotation axis is not aligned with the minor axis of the AGB isodensity profiles and this remains a mystery.
