- ID:
- ivo://CDS.VizieR/J/A+A/619/A155
- Title:
- Open cluster kinematics with Gaia DR2
- Short Name:
- J/A+A/619/A155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The distribution of open clusters in the 6D phase space is revisited with Gaia DR2. The weighted mean radial velocity (RV) of open clusters was determined, using the most probable members available from a previous astrometric investigation that also provided mean parallaxes and proper motions. Those parameters, all derived from Gaia DR2 only, were combined to provide the 6D phase-space information of 861 clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/4285
- Title:
- Open cluster King 1 photometry
- Short Name:
- J/MNRAS/470/4285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the poorly studied open cluster King 1 in the second Galactic quadrant. From wide-field photometry, we have studied the spatial distribution of this cluster. We determined that the centre of King 1 is located at {alpha}_2000_=00:22 and {delta}_2000_=+64:23. By parameterizing the stellar density with a King profile, we have obtained a central density of {rho}_0_= 6.5+/-0.2star/arcmin^2^ and a core radius of r_core_=1.9+/-0.2arcmin. By comparing the observed colour-magnitude diagram of King 1 with those of similar open clusters and with different sets of isochrones, we have estimated an age of 2.8+/-0.3Gyr, a distance modulus of (m-M)_o_=10.6+/-0.1mag and a reddening of E(B-V)=0.80+/-0.05mag. To complete our analysis, we acquired medium resolution spectra for 189 stars in the area of King 1. From their derived radial velocities, we determined an average velocity <V_r_>=-53.1+/-3.1km/s. From the strength of the infrared CaII lines in red giants we have determined an average metallicity of <[M/H]>=+0.07+/-0.08dex. From spectral synthesis, we have also estimated an {alpha}-elements abundance of <[{alpha}/M]>=-0.10+/-0.08dex.
- ID:
- ivo://CDS.VizieR/J/AJ/136/118
- Title:
- Open clusters as galactic disk tracers. I.
- Short Name:
- J/AJ/136/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have begun a survey of the chemical and dynamical properties of the Milky Way disk as traced by open star clusters. In this first contribution, the general goals of our survey are outlined and the strengths and limitations of using star clusters as a Galactic disk tracer sample are discussed. We also present medium-resolution (R~150000) spectroscopy of open cluster stars obtained with the Hydra multi-object spectrographs on the Cerro Tololo Inter-American Observatory 4m and WIYN 3.5m telescopes. Here we use these data to determine the radial velocities of 3436 stars in the fields of open clusters within about 3kpc, with specific attention to stars having proper motions in the Tycho-2 catalog. Additional radial velocity members (without Tycho-2 proper motions) that can be used for future studies of these clusters were also identified.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A80
- Title:
- Open clusters in APOGEE and GALAH surveys
- Short Name:
- J/A+A/623/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Open clusters are ideal laboratories to investigate a variety of astrophysical topics, from the properties of the Galactic disk to stellar evolutionary models. Knowing their metallicity and possibly detailed chemical abundances is therefore important. However, the number of systems with chemical abundances determined from high resolution spectroscopy is still small. To increase the number of open clusters with radial velocities and chemical abundances determined from high resolution spectroscopy we used publicly available catalogues of surveys in combination with Gaia data. Open cluster stars have been identified in the APOGEE and GALAH spectroscopic surveys by cross-matching their latest data releases with stars for which high-probability astrometric membership has been derived in many clusters on the basis of the Gaia second data release. Radial velocities have been determined for 131 and 14 clusters from APOGEE and GALAH data, respectively. This is the first radial velocity determination from high resolution spectra for 16 systems. Iron abundances have been obtained for 90 and 14 systems from APOGEE and GALAH samples, respectively. To our knowledge 66 of these clusters (57 in APOGEE and 9 in GALAH) do not have previous determinations in the literature. For 90 and 7 clusters in the APOGEE and GALAH samples, respectively, we have also determined average abundances for Na, Mg, Al, Si, Ca, Cr, Mn, and Ni.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A102
- Title:
- 3794 open clusters parameters
- Short Name:
- J/A+A/652/A102
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The structure and evolution of the spiral arms of the Milky Way are basic but long-standing questions in astronomy. Especially the lifetime of spiral arms, it is still a puzzle and has not been well constrained from observations. In this work, we aim to inspect these issues by using a large catalogue of open clusters. We have compiled a catalogue of 3794 OCs based on Gaia EDR3. A majority of them have accurately determined parallaxes, proper motions and radial velocities. The age parameters for these OCs are also collected or calculated. Then, we analysed their distributions on the Galactic plane, the kinematic properties, the vertical distributions and the regressed properties of subsamples of OCs in order to better understand the nearby spiral structure and its evolution. We find evidence that the nearby spiral arms are compatible with a long lived pattern and might have remained approximately stable for the past 80 million years. Especially, the Local Arm where our Sun is currently located in, is also suggested to be long-lived in nature, and probable a major arm segment in the Milky Way. The evolutionary characteristics of nearby spiral arms show that the dynamic spiral mechanism might be not suitable for our Galaxy. Instead, the density wave theory is more consistent with the observational properties.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A116
- Title:
- Open clusters within 1.8 kpc of the Sun
- Short Name:
- J/A+A/593/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on an almost complete sample of Galactic open star clusters within 1.8kpc, we perform a comprehensive statistical analysis of various cluster parameters like spatial position, age, size, mass and extinction in order to understand the general properties of the open cluster system in the Galaxy and the Galactic structure. Based on the distribution of 1241 open clusters about the Galactic plane and in different age bins, we find the average Galactic scale height as Zh=60+/-2pc for the youngest cluster population having Age<700Myr, however, it increases up to 64+/-2pc when we also include older population of clusters. The solar offset is found to be 6.2+/-1.1pc above the formal Galactic plane. We derive a local mass density of {rho}_0_=0.090+/-0.005M_{sun}_/pc^3^ and found a negligibly small amount of dark matter in the solar neighbourhood. The reddening in the direction of clusters suggests a strong correlation with their vertical distance from the Galactic plane having a respective slope of dE(B-V)/dz=0.40+/-0.04 and 0.42+/-0.05 mag/kpc below and above the GP. We observe a linear mass-radius and mass-age relations in the open clusters and derive a slope of dR/d(logM)=2.08+/-0.10 and d(logM)/d(logT)=-0.36+/-0.05,respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A118
- Title:
- Optical activity indicators
- Short Name:
- J/A+A/627/A118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Understanding stellar activity in solar-type stars is crucial for the physics of stellar atmospheres as well as for ongoing exoplanet programmes. We aim to test how well we understand stellar activity using our own star, the Sun, as a test case. We perform a detailed study of the main optical activity indicators (CaII H & K, Balmer lines, NaI D1, D2, and HeI D3 measured for the Sun using the data provided by the HARPS-N solar-telescope feed at the Telescopio Nazionale Galileo. We make use of periodogram analyses to study solar rotation, and we use the pool variance technique to study the temporal evolution of active regions. The correlations between the different activity indicators as well as the correlations between activity indexes and the derived parameters from the cross-correlation technique are analysed. We also study the temporal evolution of these correlations and their possible relationship with indicators of inhomogeneities in the solar photosphere like sunspot number or radio flux values. The value of the solar rotation period is found in all the activity indicators, with the only exception being H{delta}. The derived values vary from 26.29 days (H{gamma} line) to 31.23 days (HeI). From an analysis of sliding periodograms we find that in most of the activity indicators the spectral power is split into several "bands" of periods around 26 and 30 days, that might be explained by the migration of active regions between the equator and a latitude of ~30{deg}, spot evolution or a combination of both effects. In agreement with previous works a typical lifetime of active regions of ~ ten rotation periods is inferred from the pooled variance diagrams. We find that H{alpha}, H{beta}, H{gamma}, H{epsilon}, and HeI show a significant correlation with the S index. Significant correlations between the contrast, bisector span, and the heliocentric radial velocity with the activity indexes are also found. We show that the full width at half maximum, the bisector, and the disc-integrated magnetic field correlate with the radial velocity variations. The correlation of the S index and H{alpha} changes with time, increasing with larger sun spot numbers and solar irradiance. A similar tendency with the S index - radial velocity correlation is also present in the data. Our results are consistent with a scenario in which higher activity favours the correlation between the S index and the H{alpha} activity indicators and between the S index and radial velocity variations.
- ID:
- ivo://CDS.VizieR/J/A+AS/92/685
- Title:
- Optical and UV Spectrum of KQ Pup
- Short Name:
- J/A+AS/92/685
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/B/ocl
- Title:
- Optically visible open clusters and Candidates
- Short Name:
- B/ocl
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a new catalogue of open clusters in the Galaxy which updates the previous catalogues of Lynga (1987, Cat. VII/92) and of Mermilliod (1995, in Information and On-Line Data in Astronomy, ed. D. Egret & M. A. Albrecht (Dordrecht: Kluwer), 127) (included in the WEBDA database, http://obswww.unige.ch/webda). New objects and new data, in particular, data on kinematics (proper motions) that were not present in the old catalogues, have been included. Virtually all the clusters (2167) presently known were included, which represents an increment of about 986 objects relative to the Lynga (1987, VII/92) catalogue. The catalogue is presented in a single table containing all the important data, which makes it easy to use. In total, 99.7% of the objects have estimates of their apparent diameters, and 74.5% have distance, E(B-V) and age determinations. Concerning the data on kinematics, 54.7% have their mean proper motions listed, 25% their mean radial velocities, and 24.2% have both information simultaneously.
- ID:
- ivo://CDS.VizieR/J/AJ/160/235
- Title:
- Optical photometry and RVs of TOI-481b and TOI-892b
- Short Name:
- J/AJ/160/235
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of two new 10 day period giant planets from the Transiting Exoplanet Survey Satellite mission, whose masses were precisely determined using a wide diversity of ground-based facilities. TOI-481b and TOI-892b have similar radii (0.99{+/-}0.01R_Jup_ and 1.07{+/-}0.02R_Jup_, respectively), and orbital periods (10.3311days and 10.6266days, respectively), but significantly different masses (1.53{+/-}0.03M_Jup versus 0.95{+/-}0.07M_Jup_, respectively). Both planets orbit metal-rich stars ([Fe/H]=+0.26{+/-}0.05dex and [Fe/H]=+0.24{+/-}0.05 for TOI-481 and TOI-892, respectively) but at different evolutionary stages. TOI-481 is a M_*_=1.14{+/-}0.02M_{odot}_, R_*_=1.66{+/-}0.02R_{odot}_ G-type star (Teff=5735{+/-}72K), that with an age of 6.7Gyr, is in the turn-off point of the main sequence. TOI-892 on the other hand, is a F-type dwarf star (Teff=6261{+/-}80K), which has a mass of M_*_=1.28{+/-}0.03M_{odot}_ and a radius of R_*_=1.39{+/-}0.02R_{odot}_. TOI-481b and TOI-892b join the scarcely populated region of transiting gas giants with orbital periods longer than 10days, which is important to constrain theories of the formation and structure of hot Jupiters.
