- ID:
- ivo://CDS.VizieR/J/MNRAS/424/1658
- Title:
- Molecular clumps in W51 giant molecular cloud
- Short Name:
- J/MNRAS/424/1658
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present a catalogue of dense molecular clumps located within the W51 giant molecular cloud (GMC). This work is based on Heterodyne Array Receiver Programme ^13^CO J=3-2 observations of the W51 GMC and uses the automated CLUMPFIND algorithm to decompose the region into a total of 1575 clumps of which 1130 are associated with the W51 GMC. We clearly see the distinct structures of the W51 complex and the high-velocity stream previously reported.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/476/3160
- Title:
- Monoceros star-forming region radial velocities
- Short Name:
- J/MNRAS/476/3160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The principal aim of this work is to study the velocity field in the Monoceros star-forming region using the radial velocity data available in the literature, as well as astrometric data from the Gaia first release. This region is a large star-forming com- plex formed by two associations named Monoceros OB1 and OB2. We have collected radial velocity data for more than 400 stars in the area of 8x12 square degrees and distance for more than 200 objects. We apply a clustering analysis in the subspace of the phase space formed by angular coordinates and radial velocity or distance data using the Spectrum of Kinematic Grouping methodology. We found four and three spatial groupings in radial velocity and distance variables, respectively, corresponding to the Local arm, the central clusters forming the associations and the Perseus arm, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/655/A4
- Title:
- MONOS II. SB1 Orbital review and analysis
- Short Name:
- J/A+A/655/A4
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Massive stars are a key element to understand the chemical and dynamical evolution of galaxies. Stellar evolution is conditioned by many factors: rotation, mass loss, and interaction with other objects are the most important ones for massive stars. During the first evolutionary stages of stars with initial masses (i.e. M_ZAMS_) in the M_ZAMS_~18-70M_{sum}_ range they are of spectral type O. Given that stars in this mass range spend roughly 90% of their lifetime as O-type stars, establishing the multiplicity frequency and binary properties of O-type stars is crucial for many fields of modern astrophysics. The aim of the MONOS project is to collect information to study Northern Galactic O-type spectroscopic binaries. In this second paper, we tackle the study of the 35 single line spectroscopic binary (SB1) systems identified in the previous paper of the series Maiz Apellaniz et al., (2019, Cat. J/A+A/626/A20) analyze our data, and review the literature on the orbits of the systems. We have measured ~4500 radial velocities for a selection of diagnostic lines for the ~700 spectra of the studied systems in our database, for which we have used two different methods: Gaussian fit for several lines per object and cross-correlation with synthetic spectra computed with the FASTWIND stellar atmospheric code. We have also explored the photometric data delivered by the TESS mission to analyze the light-curve (LC) of the systems extracting 31 of them. We have explored the possible periods with the Lomb-Scargle method and, whenever possible, calculated the orbital solutions using the SBOP&GBART codes. For those systems in which an improved solution was possible we have merged our RVs with those in the literature and calculated a combined solution. As a result of this work, of the 35 SB1 systems identified in MONOS I, we have confirmed 21 systems as SB1 with good orbits, discarded the binary nature of 6 stars (9 Sge, HD 192281, HDE 229232 AB, 68 Cyg, HD 108 and {alpha} Cam), and left 6 stars as inconclusive due to lack of data. The remaining two stars are 15 Mon Aa which has been classified as SB2 and Cyg OB2-22 C for which we find evidence that it is most likely a triple system where the O star is orbiting an eclipsing SB1. We have also recalculated 20 new orbital solutions, including the first spectroscopic orbital solution for V747 Cep. For Cyg OB2-22 C we have obtained new ephemerides but no new orbit.
- ID:
- ivo://CDS.VizieR/J/AJ/151/49
- Title:
- M6 open cluster: star members properties
- Short Name:
- J/AJ/151/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here the first abundance analysis of 44 late B-, A-, and F-type members of the young open cluster M6 (NGC 6405, age about 75 Myr). Low- and medium-resolution spectra, covering the 4500-5840 {AA} wavelength range, were obtained using the FLAMES/GIRAFFE spectrograph attached to the ESO Very Large Telescopes. We determined the atmospheric parameters using calibrations of the Geneva photometry and by adjusting the H_{beta}_ profiles to synthetic ones. The abundances of up to 20 chemical elements, from helium to mercury, were derived for 19 late B, 16 A, and 9 F stars by iteratively adjusting synthetic spectra to the observations. We also derived a mean cluster metallicity of [Fe/H]=0.07+/-0.03 dex from the iron abundances of the F-type stars. We find that for most chemical elements, the normal late B- and A-type stars exhibit larger star-to-star abundance variations than the F-type stars probably because of the faster rotation of the B and A stars. The abundances of C, O, Mg, Si, and Sc appear to be anticorrelated with that of Fe, while the opposite holds for the abundances of Ca, Ti, Cr, Mn, Ni, Y, and Ba as expected if radiative diffusion is efficient in the envelopes of these stars. In the course of this analysis, we discovered five new peculiar stars: one mild Am, one Am, and one Fm star (HD 318091, CD-32 13109, GSC 07380-01211, CP1), one HgMn star (HD 318126, CP3), and one He-weak P-rich (HD 318101, CP4) star. We also discovered a new spectroscopic binary, most likely a SB2. We performed a detailed modeling of HD 318101, the new He-weak P-rich CP star, using the Montreal stellar evolution code XEVOL which self-consistently treats all particle transport processes. Although the overall abundance pattern of this star is properly reproduced, we find that detailed abundances (in particular the high P excess) resisted modeling attempts even when a range of turbulence profiles and mass-loss rates were considered. Solutions are proposed which are still under investigation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/369/97
- Title:
- M31 planetary nebulae velocities
- Short Name:
- J/MNRAS/369/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial velocities for a sample of 721 planetary nebulae in the disc and bulge of M31, measured using the WYFFOS fibre spectrograph on the William Herschel Telescope. Velocities are determined using the [OIII] {lambda}5007 emission line. Rotation and velocity dispersion are measured to a radius of 50arcmin (11.5kpc), the first stellar rotation curve and velocity dispersion profile for M31 to such a radius. Our kinematics are consistent with rotational support at radii well beyond the bulge effective radius of 1.4kpc, although our data beyond a radius of 5kpc are limited. We present tentative evidence for kinematic substructure in the bulge of M31 to be studied fully in a later work. This paper is part of an ongoing project to constrain the total mass, mass distribution and velocity anisotropy of the disc, bulge and halo of M31.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/1962
- Title:
- M60 SLUGGS and Gemini/GMOS combined study
- Short Name:
- J/MNRAS/450/1962
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new wide-field photometry and spectroscopy of the globular clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in the Virgo cluster. Imaging of NGC 4649 was assembled from a recently obtained Hubble Space Telescope/Advanced Camera for Surveys mosaic, and new Subaru/Suprime-Cam and archival Canada-France-Hawaii Telescope/MegaCam data. About 1200 sources were followed up spectroscopically using combined observations from three multi-object spectrographs: Keck/Deep Imaging Multi-Object Spectrograph, Gemini/Gemini Multi-Object Spectrograph and Multiple Mirror Telescope/Hectospec. We confirm 431 unique GCs belonging to NGC 4649, a factor of 3.5 larger than previous data sets and with a factor of 3 improvement in velocity precision. We confirm significant GC colour bimodality and find that the red GCs are more centrally concentrated, while the blue GCs are more spatially extended. We infer negative GC colour gradients in the innermost 20kpc and flat gradients out to large radii. Rotation is detected along the galaxy major axis for all tracers: blue GCs, red GCs, galaxy stars and planetary nebulae. We compare the observed properties of NGC 4649 with galaxy formation models. We find that formation via a major merger between two gas-poor galaxies, followed by satellite accretion, can consistently reproduce the observations of NGC 4649 at different radii. We find no strong evidence to support an interaction between NGC 4649 and the neighbouring spiral galaxy NGC 4647. We identify interesting GC kinematic features in our data, such as counter-rotating subgroups and bumpy kinematic profiles, which encode more clues about the formation history of NGC 4649.
- 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.
- 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).
990. M-Subdwarfs
- ID:
- ivo://CDS.VizieR/J/AJ/113/806
- Title:
- M-Subdwarfs
- Short Name:
- J/AJ/113/806
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic classification system for M-dwarfs and M-subdwarfs based on quantitative measures of TiO and CaH features in the region 6200 - 7400 Angstroms. Our sample of cool stars covers the range from solar metallicity stars to the most extreme subdwarfs known. Using synthetic spectra computed by Allard and Hauschildt (1995), we derive metallicities for the stars. Stars are classified as dwarfs (M V), subdwarfs (sdM), or extreme subdwarfs (esdM). These classifications correspond to [m/H] = 0.0, -1.2, and -2.0 respectively. Our metallicity scale agrees with theoretical HR diagrams and HST globular cluster measurements. We discuss some nearby subdwarfs of particular interest in light of our metallicity scale. We include photometry compiled from the literature.
