- ID:
- ivo://CDS.VizieR/J/A+A/578/A27
- Title:
- RV and [Fe/H] in 5 open clusters
- Short Name:
- J/A+A/578/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters are key to studying the formation and evolution of the Galactic disc. However, there is a deficiency of radial velocity and chemical abundance determinations for open clusters in the literature. Aims. We intend to increase the number of determinations of radial velocities and metallicities from spectroscopy for open clusters. We acquired medium-resolution spectra (R~8000) in the infrared region CaII triplet lines (~8500{AA}) for several stars in five open clusters with the long-slit IDS spectrograph on the 2.5m Isaac Newton Telescope (Roque de los Muchachos Observatory, Spain). Radial velocities were obtained by cross-correlation fitting techniques. The relationships available in the literature between the strength of infrared Ca ii lines and metallicity were also used to derive the metallicity for each cluster.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/123/2490
- Title:
- RV and [Fe/H] of M31 globular cluster system
- Short Name:
- J/AJ/123/2490
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the ultimate aim of distinguishing between various models describing the formation of galaxy halos (e.g., radial or multiphase collapse and random mergers), we have completed a spectroscopic study of the globular cluster system of M31. We present the results of deep intermediate-resolution fiber-optic spectroscopy of several hundred of the M31 globular clusters using the Wide Field Fibre Optic Spectrograph at the William Herschel Telescope in La Palma, Canary Islands. These observations have yielded precise radial velocities (+/-12km/s) and metallicities (+/-0.26dex) for over 200 members of the M31 globular cluster population out to a radius of 1.5{deg} from the galaxy center. Many of these clusters have no previous published radial velocity or [Fe/H] estimates, and the remainder typically represent significant improvements over earlier determinations. We present analyses of the spatial, kinematic, and metal abundance properties of the M31 globular clusters.
- ID:
- ivo://CDS.VizieR/J/A+A/395/97
- Title:
- RV and vsini of Ib supergiant stars
- Short Name:
- J/A+A/395/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotational velocity vsini and mean radial velocity are presented for a sample of 232 Ib supergiant stars covering the spectral region F, G and K. This work is the second part of the large survey carried out with the CORAVEL spectrometer to establish the behavior of the rotation for stars evolving off the main sequence (De Medeiros & Mayor, 1999, Cat. <J/A+AS/139/433>). These data will add constraints to the study of the rotational behavior in evolved stars, as well as solid information concerning tidal interactions in binary systems and on the link between rotation, chemical abundance and activity in stars of intermediate masses.
- ID:
- ivo://CDS.VizieR/J/A+A/561/A126
- Title:
- RV and vsini of southern stars
- Short Name:
- J/A+A/561/A126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotational and radial velocities have been measured for 1589 evolved stars of spectral types F, G, and K and luminosity classes IV, III, II, and Ib, based on observations carried out with the CORAVEL spectrometers. The precision in radial velocity is better than 0.30km/s per observation, whereas rotational velocity uncertainties are typically 1.0km/s for subgiants and giants and 2.0km/s for class II giants and Ib supergiants.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/817
- Title:
- RV catalog of O-type stars in IC 2944 and Cen OB2
- Short Name:
- J/MNRAS/416/817
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using an extended set of multi-epoch high resolution high signal-to-noise ratio optical spectra, we re-address the multiplicity properties of the O-type stars in IC 2944 and in the Cen OB2 association. We present new evidence of binarity for five objects and we confirm the multiple nature of another two. We derive the first orbital solutions for HD 100099, HD 101436 and HD 101190 and we provide additional support for HD 101205 being a quadruple system. The minimal spectroscopic binary fraction in our sample is f_min_=0.57. Using numerical simulations, we show that the detection rate of our observational campaign is close to 90%, leaving thus little room for undetected spectroscopic binary systems. The statistical properties of the O-star population in IC 2944 are similar, within the uncertainties, to the results obtained in the earlier papers in this series despite the fact that sample size effects limit the significance of the comparison. Using newly derived spectroscopic parallaxes, we reassess the distance to IC 2944 and obtained 2.3+/-0.3kpc, in agreement with previous studies. We also confirm that, as far as the O stars are concerned, the IC 2944 cluster is most likely a single entity.
- ID:
- ivo://CDS.VizieR/J/A+A/550/A107
- Title:
- RV catalogue of O stars in 30 Doradus
- Short Name:
- J/A+A/550/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Tarantula Nebula in the Large Magellanic Cloud is our closest view of a starburst region and is the ideal environment to investigate important questions regarding the formation, evolution and final fate of the most massive stars. We analyze the multiplicity properties of the massive O-type star population observed through multi-epoch spectroscopy in the framework of the VLT-FLAMES Tarantula Survey. With 360 O-type stars, this is the largest homogeneous sample of massive stars analyzed to date. We use multi-epoch spectroscopy and variability analysis to identify spectroscopic binaries. We also use a Monte-Carlo method to correct for observational biases. By modelling simultaneously the observed binary fraction, the distributions of the amplitudes of the radial velocity variations and the distribution of the time scales of these variations, we derive the intrinsic current binary fraction and period and mass-ratio distributions. We observe a spectroscopic binary fraction of 0.35+/-0.03, which corresponds to the fraction of objects displaying statistically significant radial velocity variations with an amplitude of at least 20km/s . We compute the intrinsic binary fraction to be 0.51+/-0.04. We adopt power-laws to describe the intrinsic period and mass-ratio distributions: f(log_10_P/d)~(log_10_ P/d)^pi^ (with log_10_P/d in the range 0.15-3.5) and f(q)~q^kappa^ with 0.1<q=M2/M1< 1.0. The power-law indexes that best reproduce the observed quantities are pi=-0.45+/-0.30 and kappa=-1.0+/-0.4. The period distribution that we obtain thus favours shorter period systems compared to an Opik law (pi=0). The mass ratio distribution is slightly skewed towards low mass ratio systems but remains incompatible with a random sampling of a classical mass function (kappa=-2.35). The binary fraction seems mostly uniform across the field of view and independent of the spectral types and luminosity classes. The binary fraction in the outer region of the field of view (r>7.8 , i.e. ~117pc) and among the O9.7 I/II objects are however significantly lower than expected from statistical fluctuations. The observed and intrinsic binary fractions are also lower for the faintest objects in our sample (Ks>15.5mag), which results from observational effects and the fact that our O star sample is not magnitude-limited but is defined by a spectral-type cutoff. We also conclude that magnitude-limited investigations are biased towards larger binary fractions. Using the multiplicity properties of the O stars in the Tarantula region and simple evolutionary considerations, we estimate that over 50% of the current O star population will exchange mass with its companion within a binary system. This shows that binary interaction is greatly affecting the evolution and fate of massive stars, and must be taken into account to correctly interpret unresolved populations of massive stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/400/1479
- Title:
- RV catalogue of O-type stars in NGC 6611
- Short Name:
- J/MNRAS/400/1479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on a set of over 100 medium- to high-resolution optical spectra collected from 2003 to 2009, we investigate the properties of the O-type star population in NGC 6611 in the core of the Eagle Nebula (M16). Using a much more extended data set than previously available, we revise the spectral classification and multiplicity status of the nine O-type stars in our sample. We confirm two suspected binaries and derive the first SB2 orbital solutions for two systems. We further report that two other objects are displaying a composite spectrum, suggesting possible long- period binaries. Our analysis is supported by a set of Monte-Carlo simulations, allowing us to estimate the detection biases of our campaign and showing that the latter do not affect our conclusions. The absolute minimal binary fraction in our sample is f_min_=0.44 but could be as high as 0.67 if all the binary candidates are confirmed. As in NGC 6231 (see Paper I, Sana et al., Cat. J/MNRAS/386/447), up to 75% of the O star population in NGC 6611 are found in an O+OB system, thus implicitly excluding random pairing from a classical IMF as a process to describe the companion association in massive binaries. No statistical difference could be further identified in the binary fraction, mass-ratio and period distributions between NGC 6231 and NGC 6611, despite the difference in age and environment of the two clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/447
- Title:
- RV catalogue of O-type stars in NGC 6231
- Short Name:
- J/MNRAS/386/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a long-term high-resolution spectroscopy campaign on the O-type stars in NGC 6231. We revise the spectral classification and multiplicity of these objects and we constrain the fundamental properties of the O-star population. Almost three quarters of the O-type stars in the cluster are members of a binary system. The minimum binary fraction is 0.63, with half the O-type binaries having an orbital period of the order of a few days. The eccentricities of all the short-period binaries are revised downward, and henceforth match a normal period-eccentricity distribution. The mass-ratio distribution shows a large preference for O+OB binaries, ruling out the possibility that, in NGC 6231, the companion of an O-type star is randomly drawn from a standard IMF. Obtained from a complete and homogeneous population of O-type stars, our conclusions provide interesting observational constraints to be confronted with the formation and early-evolution theories of O stars.
- ID:
- ivo://CDS.VizieR/J/other/Sci/337.444
- Title:
- RV curves of Galactic massive O stars
- Short Name:
- J/other/Sci/337.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, X-ray binaries and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. Over seventy per cent of all massive stars will exchange mass with a companion, leading to a binary merger in one third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.
- ID:
- ivo://CDS.VizieR/J/MNRAS/423/1503
- Title:
- RV curves of WASP-16, 25 and 31
- Short Name:
- J/MNRAS/423/1503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new measurements of the Rossiter-McLaughlin (RM) effect for three Wide Angle Search for transiting Planets (WASP) planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis of their complete sets of photometric and spectroscopic data.
