- ID:
- ivo://CDS.VizieR/J/A+A/603/A85
- Title:
- M67 stars radial velocities
- Short Name:
- J/A+A/603/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a seven-year-long radial velocity survey of a sample of 88 main-sequence and evolved stars to reveal signatures of Jupiter-mass planets in the solar-age and solar-metallicity open cluster M67. We analysed precise radial velocity (RV) measurements obtained with five different instruments. We conducted Monte Carlo simulations to estimate the occurrence rate of giant planets in our radial velocity survey. All the planets previously announced in this RV campaign with their properties are summarised: 3 hot Jupiters around the main-sequence stars YBP1194, YBP1514, and YBP401, and 1 giant planet around the evolved star S364. Two additional planet candidates around the stars YBP778 and S978 are also analysed. We discuss stars that exhibit large RV variability or trends individually. We find an occurrence of giant planets of ~18.0% in a selected period-mass range. This frequency is slightly higher but consistent within the errors with the estimate for the field stars, leading to the general conclusion that open cluster and field statistics agree. However, we find that the rate of hot Jupiters in the cluster (~5.7%) is substantially higher than in the field.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/465/3515
- Title:
- M13 stars radial velocities
- Short Name:
- J/MNRAS/465/3515
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use radial velocities from spectra of giants obtained with the WIYN telescope, coupled with existing chemical abundance measurements of Na and O for the same stars, to probe the presence of kinematic differences among the multiple populations of the globular cluster (GC) M13. To characterize the kinematics of various chemical subsamples, we introduce a method using Bayesian inference along with a Markov chain Monte Carlo algorithm to fit a six-parameter kinematic model (including rotation) to these subsamples. We find that the so-called extreme population (Na-enhanced and extremely O-depleted) exhibits faster rotation around the centre of the cluster than the other cluster stars, in particular, when compared with the dominant `intermediate' population (moderately Na-enhanced and O-depleted). The most likely difference between the rotational amplitude of this extreme population and that of the intermediate population is found to be 4km/s , with a 98.4 per cent probability that the rotational amplitude of the extreme population is larger than that of the intermediate population. We argue that the observed difference in rotational amplitudes, obtained when splitting subsamples according to their chemistry, is not a product of the long-term dynamical evolution of the cluster, but more likely a surviving feature imprinted early in the formation history of this GC and its multiple populations. We also find an agreement (within uncertainties) in the inferred position angle of the rotation axis of the different subpopulations considered. We discuss the constraints that these results may place on various formation scenarios.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/31
- Title:
- M-subdwarf research. I. LAMOST DR4 spectra obs.
- Short Name:
- J/ApJS/240/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a revision of the system developed by Lepine+ (2007ApJ...669.1235L) for spectroscopic M-subdwarf classification. Based on an analysis of subdwarf spectra and templates from Savcheva+ (2014ApJ...794..145S), we show that the CaH1 feature originally proposed by Gizis (1997, J/AJ/113/806) is important in selecting reliable cool subdwarf spectra. This index should be used in combination with the [TiO5, CaH2+CaH3] relation provided by Lepine+ to avoid misclassification results. In the new system, the dwarf-subdwarf separators are first derived from a sample of more than 80000 M dwarfs and a "labeled" subdwarf subsample, and these objects are all visually identified from their optical spectra. Based on these two samples, we refit the initial [TiO5, CaH1] relation and propose a new [CaOH, CaH1] relation supplementing the [TiO5, CaH1] relation to reduce the impact of uncertainty in flux calibration on classification accuracy. In addition, we recalibrate the {zeta}TiO/CaH parameter defined in Lepine+ to enable its successful application to Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. Using this new system, we select candidates from LAMOST Data Release 4 and finally identify a set of 2791 new M-subdwarf stars, covering the spectral sequence from type M0 to M7. This sample contains a large number of objects located at low Galactic latitudes, especially in the Galactic anti-center direction, expanding beyond previously published halo- and thick disk-dominated samples. Besides, we detect magnetic activity in 141 objects. We present a catalog for this M-subdwarf sample, including radial velocities, spectral indices and errors, and activity flags, with a compilation of external data (photometric and Gaia Data Release 2 astrometric parameters).
- ID:
- ivo://CDS.VizieR/J/A+A/552/A40
- Title:
- MSX high-contrast IRDCs with NH_3_
- Short Name:
- J/A+A/552/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Despite increasing research in massive star formation, little is known about its earliest stages. Infrared Dark Clouds (IRDCs) are cold, dense and massive enough to harbour the sites of future high-mass star formation. But up to now, mainly small samples have been observed and analysed. To understand the physical conditions during the early stages of high-mass star formation, it is necessary to learn more about the physical conditions and stability in relatively unevolved IRDCs. Thus, for characterising IRDCs studies of large samples are needed. We investigate a complete sample of 220 northern hemisphere high-contrast IRDCs using the ammonia (1,1)- and (2,2)-inversion transitions. We detected ammonia (1,1)-inversion transition lines in 109 of our IRDC candidates. Using the data we were able to study the physical conditions within the star-forming regions statistically. We compared them with the conditions in more evolved regions which have been observed in the same fashion as our sample sources. Our results show that IRDCs have, on average, rotation temperatures of 15K, are turbulent (with line width FWHMs around 2km/s), have ammonia column densities on the order of 10^14^cm^-2^ and molecular hydrogen column densities on the order of 10^22^cm^-2^. Their virial masses are between 100 and a few 1000M_{sun}_. The comparison of bulk kinetic and potential energies indicate that the sources are close to virial equilibrium. IRDCs are on average cooler and less turbulent than a comparison sample of high-mass protostellar objects, and have lower ammonia column densities. Virial parameters indicate that the majority of IRDCs are currently stable, but are expected to collapse in the future.
- ID:
- ivo://CDS.VizieR/J/A+AS/124/75
- Title:
- Multiple star catalogue (MSC)
- Short Name:
- J/A+AS/124/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data on 728 stellar systems of multiplicity 3 to 7 are given. All systems are physical and, with little exception, hierarchical. They are represented as several "elementary binaries". For each binary the orbital period and separation are given, as well as component magnitudes, spectral types and estimated masses. Orbital elements are also given when available. The present (1999) version of the catalogue is updated as compared to the original 1997 publication, with some changes in the format.
- ID:
- ivo://CDS.VizieR/J/A+A/394/151
- Title:
- Multiplicity among chemically peculiar stars II
- Short Name:
- J/A+A/394/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new orbits for sixteen Ap spectroscopic binaries, four of which might in fact be Am stars, and give their orbital elements. Four of them are SB2 systems: HD 5550, HD 22128, HD 56495 and HD 98088. The twelve other stars are : HD 9996, HD 12288, HD 40711, HD 54908, HD 65339, HD 73709, HD 105680, HD 138426, HD 184471, HD 188854, HD 200405 and HD 216533. Rough estimates of the individual masses of the components of HD 65339 (53 Cam) are given, combining our radial velocities with the results of speckle interferometry and with Hipparcos parallaxes. Considering the mass functions of 74 spectroscopic binaries from this work and from the literature, we conclude that the distribution of the mass ratio is the same for cool Ap stars as for normal G dwarfs. Therefore, the only differences between binaries with normal stars and those hosting an Ap star lie in the period distribution: except for the case of HD 200405, all orbital periods are longer than (or equal to) 3 days. A consequence of this peculiar distribution is a deficit of null eccentricities. There is no indication that the secondary has a special nature, like e.g. a white dwarf.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A29
- Title:
- Multiplicity of red supergiants in NGC 330
- Short Name:
- J/A+A/635/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The multiplicity properties of massive stars are one of the important outstanding issues in stellar evolution. Quantifying the binary statistics of all evolutionary phases is essential to paint a complete picture of how and when massive stars interact with their companions, and to determine the consequences of these interactions. We investigate the multiplicity of an almost complete census of red supergiant stars (RSGs) in NGC 330, a young massive cluster in the Small Magellanic Cloud. Using a combination of multi-epoch HARPS and MUSE spectroscopy, we estimate radial velocities and assess the kinematic and multiplicity properties of 15 RSGs in NGC 330. Radial velocities are estimated to better than +/-100m/s for the HARPS data. The line-of-sight velocity dispersion for the cluster is estimated as {sigma}_1D_=3.20^+0.69^_-0.52_km/s. When virial equilibrium is assumed, the dynamical mass of the cluster is log(M_dyn_/M_{sun}_)=5.20+/-0.17, in good agreement with previous upper limits. We detect significant radial velocity variability in our multi-epoch observations and distinguish between variations caused by atmospheric activity and those caused by binarity. The binary fraction of NGC 330 RSGs is estimated by comparisons with simulated observations of systems with a range of input binary fractions. In this way, we account for observational biases and estimate the intrinsic binary fraction for RSGs in NGC 330 as f_RSG_=0.3+/-0.1 for orbital periods in the range 2.3<logP[days]<4.3, with q>0.1. Using the distribution of the luminosities of the RSG population, we estimate the age of NGC 330 to be 45+/-5Myr and estimate a red straggler fraction of 50%. We estimate the binary fraction of RSGs in NGC 330 and conclude that it appears to be lower than that of main-sequence massive stars, which is expected because interactions between an RSG and a companion are assumed to effectively strip the RSG envelope.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/191
- Title:
- Multitransition CS-study towards H2O masers
- Short Name:
- J/A+AS/118/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed CS and C^34^S emission towards 33 H_2_O maser positions in the southern sky ({delta}<-28deg) using the SEST telescope. Most of the sources were selected also for their association with strong IRAS sources. CS(2-1) was detected in all sources, with the possible exception of two. Most sources were also mapped in the transitions CS(5-4) and C^34^S(2-1) and half of the sample also in CS(2-1). CS and C^34^S transitions J=2-1, J=3-2 J=5-4 were measured towards the centres of the clouds as determined from the mapping. CS and C^34^S transitions J=7-6 were measured in about a half dozen clouds. CO(1-0) was measured in most clouds in order to determine the kinetic temperatures. The CS column densities were calculated using the LTE approximation. All measurements were also analyzed using a spherical LVG model. We present the observational data and the results of this analysis.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/777
- Title:
- Multiwavelength study of RX J1117.4+0743
- Short Name:
- J/ApJ/664/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of the poor cluster RX J1117.4+0743 ([VMF98] 097) at z=0.485, based on GMOS/Gemini South g' and r' photometry and spectroscopy, and XMM-Newton observations. We examine its nature and surroundings by analyzing the projected galaxy distribution, the galaxy velocity distribution, the weak-lensing mass reconstruction, and the X-ray spectroscopy and imaging.
- ID:
- ivo://CDS.VizieR/J/A+A/632/A3
- Title:
- MUSE binaries in NGC 3201
- Short Name:
- J/A+A/632/A3
- Date:
- 09 Feb 2022 07:38:27
- Publisher:
- CDS
- Description:
- We utilize multi-epoch MUSE spectroscopy to study binaries in the core of NGC 3201. Our sample consists of 3553 stars with 54883 spectra in total comprising 3200 main-sequence stars up to 4 magnitudes below the turn-off. Each star in our sample has between 3 and 63 (with a median of 14) reliable radial velocity (RV) measurements within five years of observations. We introduce a statistical method to determine the probability of a star showing RV variations based on the whole inhomogeneous RV sample. Using HST photometry and an advanced dynamical MOCCA simulation of this specific GC we overcome observational biases that previous spectroscopic studies had to deal with. This allows us to infer a binary frequency in the MUSE FoV and enables us to deduce the underlying true binary frequency of (6.75+/-0.72)% in NGC 3201. The comparison of the MUSE observations with the MOCCA simulation suggests a significant fraction of primordial binaries. We can also confirm a radial increase of the binary fraction towards the GC centre due to mass segregation. We discovered that in our sample at least (57.5+/-7.9)% of blue straggler stars (BSS) are in a binary system. For the first time in a study of GCs, we were able to fit Keplerian orbits to a significant sample of 95 binaries. We present the binary system properties of eleven BSS and show evidence that two BSS formation scenarios, the mass transfer in binary (or triple) star systems and the coalescence due to binary-binary interactions, are present in our data. We also describe the binary and spectroscopic properties of four sub-subgiant (or red straggler) stars. Furthermore, we discovered two new black hole (BH) candidates with minimum masses (Msini) of (7.68+/-0.50)M_{sun}_, (4.4+/-2.8)M_{sun}_, and refine the minimum mass estimate on the already published BH to (4.53+/-0.21)M_{sun}_. These BHs are consistent with an extensive BH subsystem hosted by NGC 3201.