- ID:
- ivo://CDS.VizieR/J/A+A/525/A16
- Title:
- ubvy light curves of CP stars in open clusters
- Short Name:
- J/A+A/525/A16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric variability of chemically peculiar (CP) stars of the upper main sequence is closely connected to their local stellar magnetic field and their rotational period. Long term investigations, as presented here, help us to identify possible stellar cycles (as in the Sun). Photoelectric Stroemgren uvby time series for 27 CP stars within the boundaries of open clusters are presented. Our observations cover a time period of about six years (1986 to 1992) with typically fifteen measurements for each objects. These observations help us to determine the rotational periods of these objects. We established, for the first time, variability for fourteen CP stars. For additional two stars, a merging of already published data sets, resulted in more precise periods, whereas for six objects, the published periods could be confirmed. Last, but not least, no significant variations were found for five stars. Apart from six stars, all targets seem to be members of their host open clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/5184
- Title:
- UCAC5 open clusters membership and proper motion
- Short Name:
- J/MNRAS/478/5184
- Date:
- 10 Dec 2021 14:08:57
- Publisher:
- CDS
- Description:
- We present mean proper motions and membership probabilities of individual stars for optically visible open clusters, which have been determined using data from the UCAC5 catalogue. This follows our previous studies with the UCAC2 and UCAC4 catalogues, but now using improved proper motions in the GAIA reference frame. In the present study results were obtained for a sample of 1108 open clusters. For five clusters, this is the first determination of mean proper motion, and for the whole sample, we present results with a much larger number of identified astrometric member stars than on previous studies. It is the last update of our Open cluster Catalogue based on proper motion data only. Future updates will count on astrometric, photometric and spectroscopic GAIA data as input for analyses.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1409
- Title:
- u'g'r'i'z' photometry in NGC 188
- Short Name:
- J/AJ/133/1409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We continue our series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here we present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. We fit the Padova theoretical isochrones to our data. Assuming a solar metallicity for NGC 188, we find a distance of 1700+/-100pc, an age of 7.5+/-0.7Gyr, and a reddening E(B-V) of 0.025+/-0.005. This yields a distance modulus of 11.23+/-0.14.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2210
- Title:
- u'g'r'i'z' photometry in NGC 2548 (M48)
- Short Name:
- J/AJ/127/2210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. While our entire observed sample covers more than 100 clusters, here we present data for NGC 2548 (M48), which is a cluster characterized in the UBV and DDO photometric systems. We compare our results to the published values from other observers and to the Padova theoretical isochrones and metallicity curves. These observations demonstrate that the u'g'r'i'z' filters can play an important role in determining the metallicity of stars and clusters. We begin this series of papers with a study of NGC 2548 because we have obtained data on this cluster not only with our main program telescope, the CTIO Curtis Schmidt, but also with the US Naval Observatory (USNO) 1.0m telescope (the telescope used to define the u'g'r'i'z' system), and with the Sloan Digital Sky Survey (SDSS) 0.5m Photometric Telescope (the photometric monitoring telescope used to calibrate the SDSS 2.5m telescope imaging data). We have used the data from this study to validate our ability to transform measurements obtained on other telescopes to the standard USNO 1.0m u'g'r'i'z' system. This validation is particularly important for very red stars, for which the original u'g'r'i'z' standard star network is poorly constrained.
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/1495
- Title:
- UKIDSS Galactic Clusters Survey Pleiades members
- Short Name:
- J/MNRAS/422/1495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep wide-field near-infrared survey of the entire Pleiades cluster recently released as part of the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters Survey (GCS) Data Release 9 (DR9). We have identified a sample of ~1000 Pleiades cluster member candidates combining photometry in five near-infrared passbands and proper motions derived from the multiple epochs provided by the UKIDSS GCS DR9. We also provide revised membership for all previously published Pleiades low-mass stars and brown dwarfs in the past decade recovered in the UKIDSS GCS DR9 Pleiades survey based on the new photometry and astrometry provided by the GCS.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/3403
- Title:
- UKIDSS-GCS {alpha} Per members
- Short Name:
- J/MNRAS/426/3403
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep (J=19.1mag) infrared (ZY JHK) survey over the full {alpha} Per open cluster extracted from the Data Release 9 of the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Clusters Survey (UKIDSS). We have selected ~700 cluster member candidates in ~56 square degrees in {alpha} Per by combining photometry in five near-infrared passbands and proper motions derived from the multiple epochs provided by the UKIDSS Galactic Clusters Survey (GCS) Data Release 9 (DR9). We also provide revised membership for all previously published {alpha} Per low-mass stars and brown dwarfs recovered in GCS based on the new photometry and astrometry provided by DR9.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/3419
- Title:
- UKIDSS GCS Praesepe members
- Short Name:
- J/MNRAS/426/3419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Over the past decades open clusters have been the subject of many studies. Such studies are crucial considering that the universality of the initial mass function is still a subject of current investigations. Praesepe is an interesting open cluster for the study of the stellar and substellar mass function (MF), considering its intermediate age and its nearby distance. Here we present the results of a wide-field, near-infrared study of Praesepe using the Data Release 9 of the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Clusters Survey. We obtained cluster candidates of Praesepe based on a 3{sigma} astrometric and five-band photometric selection.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/3222
- Title:
- UKIDSS GCS Upper Sco members
- Short Name:
- J/MNRAS/431/3222
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a proper motion wide-field near-infrared survey of the entire Upper Sco (USco) association (about 160 square degrees) released as part of the UKIRT Infrared Deep Sky (UKIDSS) Galactic Clusters Survey (GCS) Data Release 10 (DR10). We have identified a sample of about 400 astrometric and photometric member candidates combining proper motions and photometry in five near-infrared passbands and another 286 with HK photometry and 2MASS/GCS proper motions. We also provide revised membership for all previously published USco low-mass stars and substellar members based on our selection and identify new candidates, including in regions affected by extinction. We find negligible variability between the two K-band epochs, below the 0.06mag rms level. We estimate an upper limit of 2.2% for wide common proper motions with projected physical separations less than 15000AU. We derive a disk frequency for USco low-mass stars and brown dwarfs between 26 and 37%, in agreement with estimates in IC 348 and sigma Ori. We derive the mass function of the association and find it consistent with the (system) mass function of the solar neighbourhood and other clusters surveyed by the GCS in the 0.2-0.03M_{sun}_ mass range. We confirm the possible excess of brown dwarfs in USco.
- ID:
- ivo://CDS.VizieR/J/A+AS/145/399
- Title:
- UKS 2 open cluster BV photometry
- Short Name:
- J/A+AS/145/399
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Colour-magnitude diagrams are presented for the first time, of the faint southern star cluster UKS 2, which was for a long time reported as a globular cluster candidate. The V vs. B-V diagrams indicate that UKS 2 is an open cluster with age comparable to that of the Hyades. It has a reddening of E(B-V)=0.40 and is located at a distance from the Sun of d_{sun}_=~7kpc. The cluster is located outside the solar radius at galactocentric distance projected on the plane r_GC_=~11kpc, and a height z=~-370pc.
- ID:
- ivo://CDS.VizieR/J/ApJ/836/34
- Title:
- 24um excesses in clusters & membership of NGC2244
- Short Name:
- J/ApJ/836/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We characterize the first 40 Myr of evolution of circumstellar disks through a unified study of the infrared properties of members of young clusters and associations with ages from 2Myr up to ~40Myr: NGC1333, NGC1960, NGC2232, NGC2244, NGC2362, NGC2547, IC348, IC2395, IC4665, ChamaeleonI, OrionOB1a and OB1b, Taurus, the {beta} Pictoris Moving Group, {rho} Ophiuchi, and the associations of Argus, Carina, Columba, Scorpius-Centaurus, and Tucana-Horologium. Our work features: (1) a filtering technique to flag noisy backgrounds; (2) a method based on the probability distribution of deflections, P(D), to obtain statistically valid photometry for faint sources; and (3) use of the evolutionary trend of transitional disks to constrain the overall behavior of bright disks. We find that the fraction of disks three or more times brighter than the stellar photospheres at 24{mu}m decays relatively slowly initially and then much more rapidly by ~10Myr. However, there is a continuing component until ~35Myr, probably due primarily to massive clouds of debris generated in giant impacts during the oligarchic/chaotic growth phases of terrestrial planets. If the contribution from primordial disks is excluded, the evolution of the incidence of these oligarchic/chaotic debris disks can be described empirically by a log-normal function with the peak at 12-20Myr, including ~13% of the original population, and with a post-peak mean duration of 10-20Myr.
