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741. UBVRI and infrared photometry of NGC 2215
ID:
ivo://CDS.VizieR/J/AJ/149/190
Title:
UBVRI and infrared photometry of NGC 2215
Short Name:
J/AJ/149/190
Date:
21 Oct 2021
Publisher:
CDS
Description:
Optical UBVRI photometric measurements using the Faulkes Telescope North were taken in early 2011 and combined with 2MASS JHK_s_ and WISE infrared photometry as well as UCAC4 proper motion data in order to estimate the main parameters of the galactic open cluster NGC 2215 of which large uncertainty exists in the current literature. Fitting a King model we estimate a core radius of 1.12'+/-0.04'(0.24+/-0.01pc) and a limiting radius of 4.3'+/-0.5'(0.94+/-0.11pc) for the cluster. The results of isochrone fits indicates an age of log(t)=8.85+/-0.10 with a distance of d=790+/-90pc, a metallicity of [Fe/H]=-0.40+/-0.10dex, and a reddening of E(B-V)=0.26+/-0.04. A proportion of the work in this study was undertaken by Australian and Canadian upper secondary school students involved in the Space to Grow astronomy education project, and is the first scientific publication to have utilized our star cluster photometry curriculum materials.
742. UBV(RI)cHalpha photometry in omega Cen
ID:
ivo://CDS.VizieR/J/A+A/493/959
Title:
UBV(RI)cHalpha photometry in omega Cen
Short Name:
J/A+A/493/959
Date:
21 Oct 2021
Publisher:
CDS
Description:
omega Centauri is the most well studied Galactic Globular Cluster because of its numerous puzzling features: significant dispersion in metallicity, multiple populations, triple main-sequence, horizontal branch morphology, He-rich population(s), and extended star-formation history. Intensive spectroscopic follow-up observing campaigns targeting stars at different positions in the color-magnitude diagram promises to clarify some of these peculiarities. To be able to target cluster members reliably during spectroscopic surveys and both spatial and radial distributions in the cluster outskirts without including field stars, a high quality proper-motion catalog of omega Cen and membership probability determination are required. The only available wide field proper-motion catalog of omega Cen is derived from photographic plates, and only for stars brighter than B~16. Using ESO archive data, we create a new, CCD-based, proper-motion catalog for this cluster, extending to B~20. We used high precision astrometric software developed specifically for data acquired by WFI@2.2m telescope and presented in the first paper of this series.
743. UBVRI photometry of NGC559 stars
ID:
ivo://CDS.VizieR/J/MNRAS/437/804
Title:
UBVRI photometry of NGC559 stars
Short Name:
J/MNRAS/437/804
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present UBVRI photometry of stars in the field of the intermediate-age open cluster NGC 559. By determining the stellar membership probabilities derived through a photometric and kinematic study of the cluster, we identify the 22 most probable cluster members. These are used to obtain robust cluster parameters. The mean proper motion of the cluster is {mu}_x_=-3.29+/-0.35, {mu}_y_=-1.24+/-0.28mas/yr. The radial distribution of the stellar surface density gives a cluster radius of 4.5+/-0.2arcmin (3.2+/-0.2pc). By fitting solar metallicity stellar isochrones to the colour-colour and colour-magnitude diagrams, we find a uniform cluster reddening of E(B-V)=0.82+/-0.02. The cluster has an age of 224+/-25Myr and is at a distance of 2.43+/-0.23kpc. From the optical and near-infrared two-colour diagrams, we obtain colour excesses in the direction of the cluster E(V-K)=2.14+/-0.02, E(J-K)=0.37+/-0.01 and E(B-V)=0.76+/-0.04. A total-to-selective extinction of R_V_=3.5+/-0.1 is found in the direction of the cluster which is marginally higher than the normal value. We derive the luminosity function and the mass function for the cluster main sequence. The mass function slope is found to be -2.12+/-0.31. We find evidence of mass segregation in this dynamically relaxed cluster.
744. UBVRI standard stars at +50{deg} declination
ID:
ivo://CDS.VizieR/J/AJ/146/131
Title:
UBVRI standard stars at +50{deg} declination
Short Name:
J/AJ/146/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBVRI photoelectric observations have been made of 335 stars around the sky, and centered approximately at +50{deg} declination. The majority of the stars fall in the magnitude range 9<V<16, and in the color range -0.3<(B-V)<+1.8. Those 243 stars best suited as new broadband photometric standard stars average 12.5 measures each from data taken on 98 different nights over a period of 17 years at the Kitt Peak National and Lowell Observatories.
745. UCAC5 Catalogue
ID:
ivo://CDS.VizieR/I/340
Title:
UCAC5 Catalogue
Short Name:
I/340
Date:
21 Oct 2021
Publisher:
CDS
Description:
New astrometric reductions of the US Naval Observatory CCD Astrograph Catalog (UCAC) all-sky observations were performed from first principles using the TGAS stars in the 8 to 11 magnitude range as reference star catalog. Significant improvements in the astrometric solutions were obtained and the UCAC5 catalog of mean positions at a mean epoch near 2001 was generated. By combining UCAC5 with Gaia DR1 data new proper motions on the Gaia coordinate system for over 107 million stars were obtained with typical accuracies of 1 to 2mas/yr (R=11 to 15mag), and about 5mas/yr at 16th mag. Proper motions of most TGAS stars are improved over their Gaia data and the precision level of TGAS proper motions is extended to many millions more, fainter stars. External comparisons were made using stellar cluster fields and extragalactic sources. The TGAS data allow us to derive the limiting precision of the UCAC x, y data, which is significantly better than 1/100 pixel.
746. UCAC2 Catalogue
ID:
ivo://CDS.VizieR/I/289
Title:
UCAC2 Catalogue
Short Name:
I/289
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UCAC2 is the second release of the ongoing UCAC project, designed to observe the entire sky for R magnitudes of about 7.5 to 16. The observed positional errors are about 20 mas for the stars in the 10-14 magnitude range, and about 70 mas at the limiting magnitude of R~16. For up-to-date information on the project, see the UCAC web page at http://ad.usno.navy.mil/ucac/ . This web page will also serve as the location that the UCAC team will post addenda to the UCAC2 catalog. The UCAC2 is a high density, highly accurate, astrometric catalog of 48,330,571 stars covering the sky from -90 to +40 degrees in declination and going up to +52 degrees in some areas. The northern limit is a function of right ascension. Proper motions and photometry are provided for all stars. Positions and proper motions are on the ICRS (International Celestial Reference System) and given at the epoch J2000.0. The UCAC2 has a number of major differences with respect to UCAC1. These differences include: - much larger sky coverage - reduced systematic errors of CCD observations - positions given at a standard epoch (J2000.0) - the addition of several new catalogs for improved proper motions - photometry in the J, H, and K_s bands from the 2MASS project Additional details of the data are found in Sections 3, 4, and 5 of the "readme.txt" file. UCAC2 is the last intermediate data release before the final, all sky catalog will be constructed. Observations will end around mid 2004; the final catalog is expected out in 2005. The UCAC project, observations, and first data release are described in detail in the paper Zacharias et al. AJ 120, 2131 (2000). Versions of that and other related papers are placed on the UCAC Web page (http://ad.usno.navy.mil/ucac/). The paper describing UCAC2 is in preparation (AJ, 2003); some further details can be found in the "readme.txt" file.
747. UCAC1 Catalogue
ID:
ivo://CDS.VizieR/I/268
Title:
UCAC1 Catalogue
Short Name:
I/268
Date:
21 Oct 2021
Publisher:
CDS
Description:
The UCAC1 is a high density, highly accurate, astrometric catalog of over 27 million stars in the Southern Hemisphere in the magnitude range of about 8 to 16. This version is the first release of an ongoing project to observe the entire sky; for up-to-date information see the Web page at http://ad.usno.navy.mil/ad/ucac/ . The UCAC1 is a preliminary catalog. By avoiding all "problem cases" (see details in the "intro.txt" file) it is not complete. Positions, proper motions and errors are provided, together with approximate magnitudes in the 579-642nm range. The positional precision is about 20 mas for 9 to 14 mag and 70 mas at 16th mag. The errors of the proper motions are very heterogeneous, ranging from 1 to 35 mas/yr. The UCAC is an observational program using the U.S. Naval Observatory Twin Astrograph and a 4kx4k CCD camera, covering just over 1 square degree per frame with a scale of 0.9"/pixel. Observations started in January 1998 at Cerro Tololo Interamerican Observatory (CTIO) and are continuing. This first catalog contains data observed through 07 November 1999 at which time about 80% of the Southern Hemisphere was completed. Full sky coverage is expected by early 2003 after a re-location of the instrument to the Northern Hemisphere planned for early 2001. The UCAC1 is also available on CD-ROM from the US Naval Observatory. Direct request to nz@pisces.usno.navy.mil with UCAC1 in the subject string.
748. UCAC4 Catalogue
ID:
ivo://CDS.VizieR/I/322A
Title:
UCAC4 Catalogue
Short Name:
I/322A
Date:
21 Oct 2021
Publisher:
CDS
Description:
UCAC4 is a compiled, all-sky star catalog covering mainly the 8 to 16 magnitude range in a single bandpass between V and R. Positional errors are about 15 to 20 mas for stars in the 10 to 14 mag range. Proper motions have been derived for most of the about 113 million stars utilizing about 140 other star catalogs with significant epoch difference to the UCAC CCD observations. These data are supplemented by 2MASS photometric data for about 110 million stars and 5-band (B,V,g,r,i) photometry from the APASS (AAVSO Photometric All-Sky Survey) for over 50 million stars. UCAC4 also contains error estimates and various flags. All bright stars not observed with the astrograph have been added to UCAC4 from a set of Hipparcos and Tycho-2 stars. Thus UCAC4 should be complete from the brightest stars to about R=16, with the source of data indicated in flags. UCAC4 also provides a link to the original Hipparcos star number with additional data such as parallax found on a separate data file included in this release. The proper motions of bright stars are based on about 140 catalogs, including Hipparcos and Tycho, as well as all catalogs used for the Tycho-2 proper motion construction. Proper motions of faint stars are based on re-reductions of early epoch SPM data (-90 to about -20 deg Dec) and NPM (PMM scans of early epoch blue plates) for the remainder of the sky. These early epoch SPM data have also been combined with late epoch SPM data to arrive at proper motions partly independent from UCAC4 (Girard et al. 2011AJ....142...15G, Cat. I/320). The NPM data used in UCAC4 are not published. No Schmidt plate data are used in UCAC4. The unpublished plate measure data obtained by StarScan from the AGK2, the Hamburg Zone Astrograph, the USNO Black Birch Astrograph, and the Lick Astrograph have contributed to considerable improvement in proper motions for stars mainly in the 10 to 14 mag range (down to the UCAC limit for Lick data); however, these data do not cover all sky. Recources permitting, USNO plans to release the individual CCD observations (RA,Dec at epoch of each CCD observations) in the future. Please contact nz@usno.navy.mil if you are interested in obtaining this set of about 50 GB data. We will likely request that interested users provide an external disk drive for the data release.
749. UCAC3 Catalogue
ID:
ivo://CDS.VizieR/I/315
Title:
UCAC3 Catalogue
Short Name:
I/315
Date:
21 Oct 2021
Publisher:
CDS
Description:
UCAC3 is a compiled, all-sky star catalog covering mainly the 8 to 16 magnitude range in a single bandpass between V and R. Positional errors are about 15 to 20 mas for stars in the 10 to 14 mag range. It is supplemented by proper motions and SuperCosmos and 2MASS photometric data, as well as various flags. The proper motions of bright stars are based on about 140 catalogs, including Hipparcos and Tycho, as well as all catalogs used for the Tycho-2 proper motion construction. Proper motions of faint stars are based on a re-reduction of early epoch SPM data (-90 to -10 deg Dec) plus Schmidt plate data from the SuperCosmos project (down weighted due to systematic errors of order 100 mas). The proper motions of faint stars (R >= 13.5) therefore should be used with caution. The unpublished plate measure data from the AGK2, the Hamburg Zone Astrograph, the USNO Black Birch Astrograph, and the Lick Astrograph have considerably contributed to improve proper motions for stars mainly in the 10 to 14 mag range (down to the UCAC3 limit for Lick data); however, these data do not cover all sky. UCAC3 features a number of major differences with respect to UCAC2: - complete sky coverage - re-reduction of the pixel data with better modeling - double stars are resolved to the limit of the data - significantly improved photometry from CCD data - slightly deeper limiting magnitude with larger number of stars/area - reduced systematic errors of CCD observations - the addition of several new catalogs for improved proper motions - photometry in the B, R, and I bands from the SuperCosmos project - minor planet observations have been sorted out - identification of more high proper motion stars - match with 2MASS extended sources and LEDA galaxies Additional details will be published in the upcoming release paper (Zacharias et al. 2009) and in several technical papers describing details of the reduction procedures and results. For the latest updates see http://www.usno.navy.mil/usno/astrometry . Requests for the data DVD should be sent to ucac3@usno.navy.mil; technical questions can be addressed to nz@usno.navy.mil .
750. UCAC4 nearby star survey
ID:
ivo://CDS.VizieR/J/AJ/148/119
Title:
UCAC4 nearby star survey
Short Name:
J/AJ/148/119
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use data from the U.S. Naval Observatory fourth CCD Astrograph Catalog (UCAC4) in combination with photometry from the AAVSO Photometric All-Sky Survey and Two Micron All-Sky Survey to identify stars within 25pc of the Sun. A sample of nearby stars with accurate trigonometric parallaxes from the Research Consortium On Nearby Stars is used to generate a set of 16 new photometric color-M_K_ relations that provide distance estimates with uncertainties of 15%. This work expands the available suites of well-calibrated photometric distance relations that can be used to identify nearby stellar systems. The distance relations are used with quality cuts to extract an initial sample of stars from the UCAC4 estimated to be within 25pc. Color, proper motion, and existing literature sources are then used to obtain a clean sample of red dwarfs, while limiting the amount of contamination from background giants, resulting in a sample of 1761 candidate nearby stars within 25pc. Of these, 339 are new discoveries with no previously known published parallax or distance estimate, primarily with proper motions less than 0.2arcsec/yr. Five stars are estimated to be within 10pc, with the nearest, TYC 3980 1081 1, with V=10.50 estimated to be at 5.9pc. That several hundred new stars have been revealed so close to the Sun illustrates once again that there is considerable work yet to be done to map the solar neighborhood and that additional nearby stars are likely still to be discovered.