- 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.
Number of results to display per page
Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/98
- Title:
- 24um observations of AFGKM stars of 3 clusters
- Short Name:
- J/ApJ/750/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Spitzer Space Telescope 24 {mu}m data to search for debris disks among 122 AFGKM stars from the ~670 Myr clusters Hyades, Coma Ber, and Praesepe, utilizing a number of advances in data reduction and determining the intrinsic colors of main-sequence stars. For our sample, the 1{sigma} dispersion about the main-sequence V-K_S_, K_S_-[24] locus is approximately 3.1%. We identify seven debris disks at 10% or more ( >=3{sigma} confidence level) above the expected K_S_-[24] for purely photospheric emission. The incidence of excesses of 10% or greater in our sample at this age is 5.7^+3.1^_-1.7_%. Combining with results from the literature, the rate is 7.8^+4.2^_-2.1_% for early-type (B9-F4) stars and 2.7^+3.3^_-1.7_% for solar-like (F5-K9) stars. Our primary sample has strict criteria for inclusion to allow comparison with other work; when we relax these criteria, three additional debris disks are detected. They are all around stars of solar-like type and hence reinforce our conclusion that disks around such stars are still relatively common at 670Myr and are similar to the rate around early-type stars. The apparently small difference in decay rates between early-type and solar-like stars is inconsistent with the first-order theoretical predictions that the later type stellar disks would decay an order of magnitude more quickly than the earlier type ones.
- ID:
- ivo://CDS.VizieR/J/ApJ/446/622
- Title:
- UV and optical imagery of LH 52 and LH 53
- Short Name:
- J/ApJ/446/622
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 40' field including the stellar associations LH 52 and LH 53 and the supernova remnant N49 in the Large Magellanic Cloud was observed by the Ultraviolet Imaging Telescope (UIT) during the Astro-1 Space Shuttle mission in 1990 December. The image in the 162 nm bandpass is discussed together with ground-based BV data on subfields containing LH 52 and LH 53. Point-spread function photometry in the 162nm, B, and V bands is presented in the form of color-magnitude diagrams and two-color diagrams, which are compared with stellar models. The far-ultraviolet extinction curve of the dust in LH 52 is unusually steep for the LMC. The most probable age of both associations is ~10 Myr, which constrains the scenario for the evolution of the supergiant Halpha shell LMC 4 by stochastic self-propagated star formation. The initial mass function (IMF) slope for LH 52 is Gamma~-1, in agreement with previous work, and the slope for LH 53, which is less densely populated, is Gamma~-2. A similar relationship between surface density of stars and IMF slope is reported for a UIT field near 30 Dor. The ultraviolet morphology of N49, which is contained in LH 53, is dominated by two bright features that straddle an X-ray bright spot, consistent with an encounter between the blast wave and a cloud. The estimated age of ~10Myr for LH 53 implies an initial mass of ~20M_{sun}_ for the N49 progenitor star.
- ID:
- ivo://CDS.VizieR/J/A+A/528/A148
- Title:
- uvby{beta} photometry of early type stars
- Short Name:
- J/A+A/528/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The {beta} Cephei stars and slowly pulsating B (SPB) stars are massive main sequence variables. The strength of their pulsational driving strongly depends on the opacity of iron-group elements. As many of those stars naturally occur in young open clusters, whose metallicities can be determined in several fundamental ways, it is logical to study the incidence of pulsation in several young open clusters. To provide the foundation for such an investigation, Stroemgren-Crawford uvby{beta} photometry of open cluster target stars was carried out to determine effective temperatures, luminosities, and therefore cluster memberships. In the course of three observing runs, uvby{beta} photometry for 168 target stars was acquired and transformed into the standard system by measurements of 117 standard stars. The list of target stars also included some known cluster and field {beta} Cephei stars, as well as {beta} Cephei and SPB candidates that are targets of the asteroseismic part of the Kepler satellite mission. The uvby{beta} photometric results are presented. The data are shown to be on the standard system, and the properties of the target stars are discussed: 140 of these are indeed OB stars, a total of 101 targets lie within the {beta} Cephei and/or SPB star instability strips, and each investigated cluster contains such potential pulsators. These measurements will be taken advantage of in a number of subsequent publications.
- ID:
- ivo://CDS.VizieR/J/A+A/394/479
- Title:
- uvby{beta} photometry of h and chi Per
- Short Name:
- J/A+A/394/479
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD uvby{beta} photometry for stars in the nuclei of the young double cluster {h} and {chi} Persei. We find that the reddening is highly variable through the {h} Per nucleus, increasing from west to east, with values ranging from E(b-y)=0.328+/-0.022 in the western part to E(b-y)=0.465+/-0.025 in the south-east. Towards {chi} Persei the reddening is fairly constant, with E(b-y)=0.398+/-0.025. Both clusters share a common distance modulus of 11.7+/-0.1mag, and an age of logt=7.10+/-0.05 years.
- ID:
- ivo://CDS.VizieR/J/MNRAS/358/66
- Title:
- uvby{beta} photometry of NGC 663
- Short Name:
- J/MNRAS/358/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD uvby{beta} photometry for stars in the central area of the young open cluster NGC 663. We find that the reddening is highly variable, with values ranging from E(b-y)=0.639+/-0.032 in the central part to E(b-y)=0.555+/-0.038 in the south-east. The distance modulus is found to be 11.6+/-0.1mag. (2.1kpc), and the age logt=7.25+/-0.1 years (25+7/-5Myr).