- ID:
- ivo://CDS.VizieR/J/AJ/150/97
- Title:
- Radial velocities in M67. I. 1278 candidate members
- Short Name:
- J/AJ/150/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from 13776 radial-velocity (RV) measurements of 1278 candidate members of the old (4Gyr) open cluster M67 (NGC 2682). The measurements are the results of a long-term survey that includes data from seven telescopes with observations for some stars spanning over 40years. For narrow-lined stars, RVs are measured with precisions ranging from about 0.1 to 0.8km/s. The combined stellar sample reaches from the brightest giants in the cluster down to about 4mag below the main-sequence turnoff (V=16.5), covering a mass range of about 1.34M_{sun}_ to 0.76M_{sun}_. Spatially, the sample extends to a radius of 30arcmin (7.4pc in projection at a distance of 850pc or 6-7 core radii). We find M67 to have a mean radial velocity of +33.64km/s (with an internal precision of +/-0.03km/s) well separated from the mean velocity of the field. For stars with >=3 measurements, we derive RV membership probabilities and identify RV variables, finding 562 cluster members, 142 of which show significant RV variability. We use these cluster members to construct a color-magnitude diagram and identify a rich sample of stars that lie far from the standard single star isochrone, including the well-known blue stragglers, sub-subgiants and yellow giants. These exotic stars have a binary frequency of (at least) 80%, more than three times that detected for stars in the remainder of the sample. We confirm that the cluster is mass segregated, finding the binaries to be more centrally concentrated than the single stars in our sample at the 99.8% confidence level (and at the 98.7% confidence level when only considering main-sequence stars). The blue stragglers are centrally concentrated as compared to the solar-type main-sequence single stars in the cluster at the 99.7% confidence level. Accounting for measurement precision, we derive an RV dispersion in M67 of 0.80+/-0.04km/s for our sample of single main-sequence stars, subgiants and giants with V{<=}15.5. When corrected for undetected binaries, this sample yields a true RV dispersion of 0.59_-0.06_^+0.07^km/s. The radial distribution of the velocity dispersion is consistent with an isothermal distribution within our stellar sample. Using the cluster RV dispersion, we estimate a virial mass for the cluster of 2100_-550_^+610^M_{sun}_.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/139/1383
- Title:
- Radial velocities in M35 (NGC 2168)
- Short Name:
- J/AJ/139/1383
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 5201 radial-velocity (RV) measurements of 1144 stars as part of an ongoing study of the young (150Myr) open cluster M35 (NGC 2168). We have observed M35 since 1997, using the Hydra Multi-Object Spectrograph on the WIYN 3.5m telescope.
- ID:
- ivo://CDS.VizieR/III/55
- Title:
- Radial Velocities in Open Clusters
- Short Name:
- III/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This compilation contains more than 5700 individual radial velocities for 370 stars in 4 open clusters.
- ID:
- ivo://CDS.VizieR/III/97A
- Title:
- Radial Velocities in open clusters
- Short Name:
- III/97A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This second part of the bibliography contains 6504 individual radial velocities for 774 stars in 78 open clusters. It is devoted to NGC and IC open clusters. The first part (Mermilliod J.-C., 1979, Bull. Inform. CDS 16,2; catalogue III/55/) contains the data for five nearby open clusters. The collected data have been found in the literature published from 1900 to the end of 1983. This catalog contains also unpublished data which have been delivered to Mermilliod by several authors.
- ID:
- ivo://CDS.VizieR/J/A+A/375/30
- Title:
- Radial velocities in open clusters
- Short Name:
- J/A+A/375/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate radial velocities and photoelectric UBV photometry for 73 and 57 red-giant candidates, respectively, in the intermediate-age open clusters NGC 2324, 2818, 3960 and 6259. These data confirm the membership of 47 stars, 12 of which (26% ) are spectroscopic binaries; three preliminary orbits have been determined in NGC 3960. From Washington photometry of 8 red giant members, the metallicity of NGC 6259 is found to be [Fe/H]=0.06+/-0.08. At the age of these clusters, most of the red giants are observed in the core-helium (clump) burning phase, the general morphology of which is well reproduced by theoretical models with convective overshooting. However, a number of bona fide cluster giant members are found significantly to the red of the isochrones fitting the rest of the CMD of these and a few other clusters. Some of these stars are binaries, but others seem to be single. In either case, their red colours and/or low luminosities remain unexplained by current stellar evolution theory.
- ID:
- ivo://CDS.VizieR/J/ApJ/639/1069
- Title:
- Radial velocities in the Cas OB6 association
- Short Name:
- J/ApJ/639/1069
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of time-resolved spectroscopy of 13 O-type stars in the Cas OB6 stellar association. We conducted a survey for radial velocity variability in search of binary systems, which are expected to be plentiful in young OB associations.
- ID:
- ivo://CDS.VizieR/J/A+A/488/409
- Title:
- Radial velocities of {alpha} Per stars
- Short Name:
- J/A+A/488/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Alpha Persei open cluster (Melotte 20) is one of the nearby clusters (d<500pc) for which a long-term systematic radial-velocity monitoring of the solar-type stars has not been published so far. We undertook an observing program in 1982 to study the membership, duplicity, and rotation of the main-sequence stars and to compare the results with those of the other nearby clusters. Radial-velocity observations of 60 solar-type stars in Mel 20 were obtained with CORAVEL, and of 44 fainter stars with ELODIE spectrographs, in the magnitude range 9.5<V<13.85 The membership of 37 stars from the list compiled by Heckmann is confirmed according to their proper motions, radial velocities, and photometry. We discovered twelve spectroscopic binaries (3 double-lined, 8 single-lined, 1 suspected) among the members and determined an orbit for the double-lined binary He 848. The observed frequency of spectroscopic binaries is therefore 32% (12/37). Four stars are photometric binaries. In addition, the membership of 33 stars with AP numbers is supported by the present radial velocities. Two single-lined and three double-lined binaries were detected in this sample. The cluster mean radial velocity is -1.39+/-0.17km/s based on 18 stars within 2{sigma}. We found a systematic difference of 3.67+/-1.48km/s between observed- and astrometric radial velocities. The Alpha Persei cluster members define a tight main sequence in the colour-magnitude diagrams. The remaining scatter observed in the colour- magnitude diagrams and in radial velocities may be due to the difficulty of separating the core Alpha Persei stars from the extended comoving stream.
- ID:
- ivo://CDS.VizieR/J/A+A/496/441
- Title:
- Radial velocities of Berkeley 32 stars
- Short Name:
- J/A+A/496/441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of lithium (Li) abundances in open clusters provide a unique tool for following the evolution of this element with age, metallicity, and stellar mass. In spite of the plethora of Li data already available, the behavior of Li in solar-type stars has so far been poorly understood. Using FLAMES/Giraffe on the VLT, we obtained spectra of 157 candidate members of the old, metal-poor cluster Berkeley 32, to determine membership and to study the Li behavior of confirmed members. Radial velocities were measured, allowing us to derive both the cluster velocity and membership information for the sample stars. The Li abundances were obtained from the equivalent width of the Li I 670.8nm feature, using curves of growth.
- ID:
- ivo://CDS.VizieR/J/A+A/448/1001
- Title:
- Radial velocities of B stars in Sco-Cen
- Short Name:
- J/A+A/448/1001
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive single-epoch radial velocities for a sample of 56 B-type stars members of the subgroups Upper Scorpius, Upper Centaurus Lupus and Lower Centaurus Crux of the nearby Sco-Cen OB association. The radial velocity measurements were obtained by means of high-resolution echelle spectra via analysis of individual lines. The internal accuracy obtained in the measurements is estimated to be typically 2-3km/s, but depends on the projected rotational velocity of the target. Radial velocity measurements taken for 2-3 epochs for the targets HD120307, HD142990 and HD139365 are variable and confirm that the y are spectroscopic binaries, as previously identified in the literature. Spectral lines from two stellar components are resolved in the observed spectra of target stars HD133242, HD133955 and HD143018, identifying them as spectroscopic binaries.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/L33
- Title:
- Radial velocities of 2 hot Jupiters in Praesepe
- Short Name:
- J/ApJ/756/L33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of two giant planets orbiting stars in Praesepe (also known as the Beehive Cluster). These are the first known hot Jupiters in an open cluster and the only planets known to orbit Sun-like, main-sequence stars in a cluster. The planets are detected from Doppler-shifted radial velocities; line bisector spans and activity indices show no correlation with orbital phase, confirming the variations are caused by planetary companions. Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264+/-0.0070 days and has a minimum mass of 0.540+/-0.039M_Jup_, and Pr0211b orbits a V=12.06 late G dwarf with a period of 2.1451+/-0.0012 days and has a minimum mass of 1.844+/-0.064M_Jup_. The detection of two planets among 53 single members surveyed establishes a lower limit of 3.8^+5.0^_-2.4_% on the hot Jupiter frequency in this metal-rich open cluster. Given the precisely known age of the cluster, this discovery also demonstrates that, in at least two cases, giant planet migration occurred within 600Myr after formation. As we endeavor to learn more about the frequency and formation history of planets, environments with well-determined properties--such as open clusters like Praesepe--may provide essential clues to this end.
