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7271. UBVRI mag of 3 Open Cluster Remnants candidates
ID:
ivo://CDS.VizieR/J/A+A/428/67
Title:
UBVRI mag of 3 Open Cluster Remnants candidates
Short Name:
J/A+A/428/67
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present CCD UBVI photometric and medium/high resolution spectroscopic observations obtained in the field of the previously unstudied dissolving open cluster candidates NGC 5385, NGC 2664 and Collinder 21. Our analysis is based on the discussion of star counts, photometry, radial velocity distribution, and proper motions available from the Tycho 2 catalogue (<I/259>). All three aggregates clearly emerge from the mean Galactic field, but, regrettably, the close scrutiny of proper motions and radial velocities reveals that we are not facing any physical group. Instead, what we are looking at are just chance alignments of a few bright unrelated stars. Our analysis casts some doubt on the Bica et al. (2001A&A...366..827B) criterion to look for Possible Open Cluster Remnants. It seems mandatory to define a better criterion to adopt for further investigations.
7272. UBVRI observations of active stars
ID:
ivo://CDS.VizieR/J/A+AS/121/369
Title:
UBVRI observations of active stars
Short Name:
J/A+AS/121/369
Date:
21 Oct 2021
Publisher:
CDS
Description:
In the framework of an extensive program focusing on the global properties and evolution of active stars, high-precision UBV(RI)_c_ photometry of 9 selected stars, collected at the European Southern Observatory over the intervals 7-17 September and 30 September - 10 October 1990, is presented. Significant evolution of the light curves, period variations and evidence for long-term variability of the global degree of spottedness are found. Some of the spectral classifications are discussed. These observations contribute to the establishment of a time-extended photometric database which can give important clues on topics such as the stability of the spotted areas, differential rotation, solar-like cycles and the correlation between inhomogeneities at different atmospheric levels. For a description of the UBV and (RI)c photometric systems, see e.g. General Catalog of Photometric Data <GCPD/01> and <GCPD/54>
7273. UBVRI observations of FKSZ stars
ID:
ivo://CDS.VizieR/II/303
Title:
UBVRI observations of FKSZ stars
Short Name:
II/303
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
7274. UBVRI phot. in seven Local Group dwarfs galaxies
ID:
ivo://CDS.VizieR/J/AJ/133/2393
Title:
UBVRI phot. in seven Local Group dwarfs galaxies
Short Name:
J/AJ/133/2393
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained UBVRI images with the Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory 4m telescopes and Mosaic cameras of seven dwarfs in (or near) the Local Group, all of which have known evidence of recent star formation: IC 10, NGC 6822, WLM, Sextans B, Sextans A, Pegasus, and Phoenix. We construct color-magnitude diagrams (CMDs) of these systems, as well as neighboring regions that can be used to evaluate the degree of foreground contamination by stars in the Milky Way.
7275. UBVRI Photometric Standards
ID:
ivo://CDS.VizieR/II/183A
Title:
UBVRI Photometric Standards
Short Name:
II/183A
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBVRI photoelectric observations have been made on the Johnson-Kron-Cousins photometric system of 526 stars centered on the celestial equator. The program stars within a 298 number subset have sufficient measures that they are capable of providing, for telescopes of intermediate and large size in both hemispheres, an internally consistent homogeneous broadband standard photometric system around the sky. The stars average 29 measures each on 19 nights. The majority of the stars in this paper fall in the magnitude range 11.5 < V < 16.0, and in the color range -0.3 < (B-V) < +2.3.
7276. UBVRI photometry and line fluxes of AG Peg
ID:
ivo://CDS.VizieR/J/A+A/604/A48
Title:
UBVRI photometry and line fluxes of AG Peg
Short Name:
J/A+A/604/A48
Date:
21 Oct 2021
Publisher:
CDS
Description:
AG Peg is known as the slowest symbiotic nova, which experienced its nova-like outburst around 1850. After 165 years, during June of 2015, it erupted again showing characteristics of the Z And-type outburst. The primary objective is to determine basic characteristics, the nature and type of the 2015 outburst of AG Peg. We achieved this aim by modelling the spectral energy distribution using low-resolution spectroscopy (330-750nm), medium-resolution spectroscopy (420-720nm; R=11000), and UBVR_C_I_C_ photometry covering the 2015 outburst with a high cadence. Optical observations were complemented with the archival HST and FUSE spectra from the preceding quiescence. During the outburst, the luminosity of the hot component was in the range of 2-11x10^37^(d/0.8kpc})^2^erg/s. To generate the maximum luminosity the white dwarf (WD) had to accrete at ~3x10^-7^M_{sun}/yr, which exceeds the stable-burning limit and thus led to blowing optically thick wind from the WD. We determined its mass-loss rate to a few x10^-6^M_{sun}/yr. At the high temperature of the ionising source, 1.5-2.3x10^5^K, the wind converted a fraction of the WD's photospheric radiation into the nebular emission that dominated the optical. A one order of magnitude increase of the emission measure, from a few x10^59^(d/0.8kpc)^2^/cm^3^ during quiescence, to a few x10^60^(d/0.8kpc)^2^/cm^3^ during the outburst, caused a 2mag brightening in the LC, which is classified as the Z And-type of the outburst. The very high nebular emission and the presence of a disk-like HI region encompassing the WD, as indicated by a significant broadening and high flux of the Raman-scattered OVI 6825{AA} line during the outburst, is consistent with the ionisation structure of hot components in symbiotic stars during active phases.
7277. UBVRI photometry and polarimetry of DF Tau
ID:
ivo://CDS.VizieR/J/A+A/448/1075
Title:
UBVRI photometry and polarimetry of DF Tau
Short Name:
J/A+A/448/1075
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of multi-year photometric and polarimetric observations of the young binary system DF Tau in UBVRI bands as well as bispectrum speckle interferometric observations in the H and K bands are presented. The photometric and polarimetric observations suggest the linear poarization variation has substantially a stochastic character.
7278. UBVRI photometry in Be 15, Be 80 and NGC 2192
ID:
ivo://CDS.VizieR/J/MNRAS/401/621
Title:
UBVRI photometry in Be 15, Be 80 and NGC 2192
Short Name:
J/MNRAS/401/621
Date:
21 Oct 2021
Publisher:
CDS
Description:
The three open clusters Be 15, Be 80 and NGC 2192 have been observed using CCD UBV(RI)C photometry at the San Pedro Martir Observatory, Mexico within the framework of our open-cluster survey. The fundamental parameters of interstellar reddening, distance and age have been derived, and also the metallicity for NGC 2192 (solar metallicity has been assumed for the other two).
7279. UBVRI photometry in cluster Tr 18
ID:
ivo://CDS.VizieR/J/A+AS/86/209
Title:
UBVRI photometry in cluster Tr 18
Short Name:
J/A+AS/86/209
Date:
21 Oct 2021
Publisher:
CDS
Description:
UBVRI photoelectric photometry was obtained in the field of the open cluster Tr 18. From the analysis of the data we confirm that several distant OB stars were wrongly assumed as cluster members in previous investigations. The true distance modulus is 10.95, equivalent to a distance of 1550pc with the adopted age of (9.0+/-1.0)x10^7^yr. The GH Car Cepheid variable is very much probably a cluster member in view of its spatial position and the average absolute magnitude. However, some arguments are given to suggest that the reality of this cluster is still an open question. The observations in the Cousins system were carried out during 9 nights in April 1989 at Cerro Tololo Interamerican Observatory, with a single channel photometer attaéched to the 60cm Lowell telescope. The positions and identifications with large astrometric surveys was achieved by B. Skiff (Lowell Obs.) in 2010.
7280. UBVRI photometry in 48 globular clusters
ID:
ivo://CDS.VizieR/J/MNRAS/485/3042
Title:
UBVRI photometry in 48 globular clusters
Short Name:
J/MNRAS/485/3042
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present wide-field, ground-based Johnson-Cousins UBVRI photometry for 48 Galactic globular clusters based on almost 90000 public and proprietary images. The photometry is calibrated with the latest transformations obtained in the framework of our secondary standard project, with typical internal and external uncertainties of order a few millimagnitudes. These data provide a bridge between existing small-area, high-precision HST photometry and all sky-catalogues from large surveys like Gaia, SDSS, or LSST. For many clusters, we present the first publicly available photometry in some of the five bands (typically U and R). We illustrate the scientific potential of the photometry with examples of surface density and brightness profiles and of colour-magnitude diagrams, with the following highlights: (i) we study the morphology of NGC 5904, finding a varying ellipticity and position angle as a function of radial distance; (ii) we show $U$-based colour-magnitude diagrams and demonstrate that no cluster in our sample is free from multiple stellar populations, with the possible exception of a few clusters with high and differential reddening or field contamination, for which more sophisticated investigations are required. This is true even for NGC 5694 and Terzan 8, that were previously considered as (mostly) single-population candidates.