- ID:
- ivo://CDS.VizieR/J/AJ/142/127
- Title:
- NGC 5822 UBVI and uvbyCaH{beta} photometry
- Short Name:
- J/AJ/142/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 5822 is a richly populated, moderately nearby, intermediate-age open cluster covering an area larger than the full moon on the sky. A CCD survey of the cluster on the UBVI and uvbyCaH{beta} systems shows that the cluster is superposed upon a heavily reddened field of background stars with E(B-V)>0.35mag, while the cluster has small and uniform reddening at E(b-y)=0.075+/-0.008mag or E(B-V)=0.103+/-0.011mag, based upon 48 and 61 probable A and F dwarf single-star members, respectively. The errors quoted include both internal photometric precision and external photometric uncertainties.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AcA/59/349
- Title:
- NGC 1502 UBVIc photometry
- Short Name:
- J/AcA/59/349
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of variability search in the field of the young open cluster NGC 1502. Eight variable stars were discovered. Of six other stars in the observed field that were suspected for variability, we confirm variability of two, including one beta Cep star, NGC 1502-26. The remaining four suspects were found to be constant in our photometry. In addition, UBVIc photometry of the well-known massive eclipsing binary SZ Cam was obtained.
- ID:
- ivo://CDS.VizieR/J/MNRAS/309/739
- Title:
- NGC 2660 UBVIc photometry
- Short Name:
- J/MNRAS/309/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVI photometry of the intermediate old open cluster NGC 2660, covering from the red giant region to about seven magnitudes below the main sequence turn-off. Using the synthetic colour-magnitude diagram method, we estimate in a self-consistent way values for distance modulus [(m-M)_0_~12.2], reddening [E(B-V)~0.40], metallicity ([Fe/H] about solar) and age (t<=1Gyr). A 30 per cent population of binary stars turns out to be probably present.
4454. NGC 6649 UBV photometry
- ID:
- ivo://CDS.VizieR/J/MNRAS/224/61
- Title:
- NGC 6649 UBV photometry
- Short Name:
- J/MNRAS/224/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A colour magnitude diagram to V=20 is given for 395 stars in the heavily reddened open cluster NGC 6649. The absorption-corrected distance modulus is 11.00+/-0.15mag (1585+/-110pc) assuming R(OB)=3.27+/-0.10 for NGC 6649 and based on a ZAMS with zero point referenced to a Pleiades distance modulus of 5.56mag. The range of reddening over the 5arcmin diameter of the cluster is {DELTA}E(B-V)=0.3mag. NGC 6649 contains the double mode Cepheid V367 Sct, which has <M_V_>=-3.80+/-0.06 and <B_0_>-<V_0_>=0.58+/-0.02.
- ID:
- ivo://CDS.VizieR/J/AJ/115/734
- Title:
- NGC 6231 UBVRI and H{alpha} photometry
- Short Name:
- J/AJ/115/734
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVRI and H{alpha} CCD photometry has been obtained for the young open cluster NGC 6231. From the R-H{alpha} color, a measure of the H{alpha} emission, we find 12 pre-main-sequence (PMS) members and seven possible PMS members in the cluster. Applying recent stellar evolutionary tracks and PMS evolutionary tracks, we derive the age, age spread, and initial mass function of the cluster. The initial mass function of NGC 6231 is a Gaussian with a turnover at logm~0.4 (m~2.5M_{Sun}_) and shows an abrupt decrease in the number of low-mass stars. Possible reasons for the suppression of low-mass star formation and star formation processes are discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/371/79
- Title:
- NGC 5548 UBVRI phot. and Halpha, Hbeta fluxes
- Short Name:
- J/A+A/371/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of a ground-based optical monitoring campaign on NGC 5548 in June 1998 are presented. The broad-band fluxes (U, B, V), and the spectrophotometric optical continuum flux F_{lambda}_ (5100{AA}) monotonically decreased in flux while the broad-band R and I fluxes and the integrated emission-line fluxes of H{alpha} and H{beta} remained constant to within 5%. On June 22, a short continuum flare was detected in the broad band fluxes. It had an amplitude of about ~18% and it lasted only =~90 min. The broad band fluxes and the optical continuum F_{lambda}_ (5100{AA}) appear to vary simultaneously with the EUV variations. No reliable delay was detected for the broad optical emission lines in response to the EUVE variations. Narrow H{beta} emission features predicted as a signature of an accretion disk were not detected during this campaign. However, there is marginal evidence for a faint feature at {lambda}=~4962{AA} with FWHM=~6{AA} redshifted by {Delta}v=~1100km/s with respect to H{beta}_narrow_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1095
- Title:
- NGC 6866 UBVRI photometry
- Short Name:
- J/MNRAS/453/1095
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD UBVRI photometry of the field of the open cluster NGC 6866. Structural parameters of the cluster are determined utilizing the stellar density profile of the stars in the field. We calculate the probabilities of the stars being physical members of the cluster, using their astrometric data, and perform further analyses using only the most probable members. The reddening and metallicity of the cluster were determined by independent methods. The LAMOST spectra and the ultraviolet excess of the F- and G-type main-sequence stars in the cluster indicate that the metallicity of the cluster is about the solar value. We estimated the reddening E(B-V)=0.074+/-0.050mag using the U-B versus B-V two-colour diagram. The distance modula, the distance and the age of NGC 6866 were derived as {mu}=10.60+/-0.10mag, d=1189+/-75pc and t=813+/-50Myr, respectively, by fitting colour-magnitude diagrams of the cluster with the PARSEC isochrones. The Galactic orbit of NGC 6866 indicates that the cluster is orbiting in a slightly eccentric orbit with e=0.12. The mass function slope x=1.35+/-0.08 was derived by using the most probable members of the cluster.
4458. NGC 3105 UBVR photometry
- ID:
- ivo://CDS.VizieR/J/A+A/616/A124
- Title:
- NGC 3105 UBVR photometry
- Short Name:
- J/A+A/616/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3105 is a young open cluster hosting blue, yellow, and red supergiants. This rare combination makes it an excellent laboratory for constraining evolutionary models of high-mass stars. It has been poorly studied, and the fundamental parameters such as its age or distance are not well defined. We intend to characterise in an accurate way the cluster and its evolved stars, for which we derive for the first time atmospheric parameters and chemical abundances. We performed a complete analysis combining UBVR photometry with spectroscopy. We obtained spectra with classification purposes for 14 blue stars and high-resolution spectroscopy for an in-depth analysis of the six other evolved stars. We identify 126 B-type likely members within a radius of 2.7+/-0.6arcmin, which implies an initial mass, Mcl~=4100M_{sun}_. We find a distance of 7.2+/-0.7kpc for NGC 3105, placing it at R_GC_=10.0+/-1.2kpc. Isochrone fitting supports an age of 28+/-6Ma, implying masses around 9.5M_{aun}_ for the supergiants. A high fraction of Be stars (~25%) is found at the top of the main sequence down to spectral type b3. From the spectral analysis we estimate for the cluster an average v_rad_=+46.9+/-0.9km/s and a low metallicity, [Fe/H]=-0.29+/-0.22. We also have determined, for the first time, chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. An overabundance of Ba is found, supporting the enhanced s-process. NGC 3105 has a low metallicity for its Galactocentric distance, comparable to typical LMC stars. It is a valuable spiral tracer in a very distant region of the Carina-Sagittarius spiral arm, a poorly known part of the Galaxy. As one of the few Galactic clusters containing blue, yellow, and red supergiants, it is massive enough to serve as a test bed for theoretical evolutionary models close to the boundary between intermediate- and high-mass stars.
- ID:
- ivo://CDS.VizieR/J/A+A/372/95
- Title:
- NGC 2439 ubvy{beta} photometry
- Short Name:
- J/A+A/372/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The structure of the field surrounding the Galactic cluster NGC 2439 is studied utilizing uvby{beta} photometry of bright OB stars. We collate all photometric and kinematic data available to identify possible groupings. The stars of our sample show a large scatter in their distances, radial velocities, proper motions and reddenings. We conclude that they do not belong to a single stellar association. We find evidence of the existence of three coherent structures at distances of 370pc, 1kpc, and 2.6-3.2kpc. The high stellar density toward NGC 2439 is very likely due to a decreased absorption in this direction, which poses some doubt on the reality of the cluster. A comprehensive uvby{beta} study of NGC 2439 is required to clarify its nature. The spatial distribution of the stars and their reddening are used to characterise the spatial distribution of the visual extinction in the region. The results obtained confirm previously determined constraints on the formation mechanism of interstellar CH^+^ towards the NGC 2439 field.
- ID:
- ivo://CDS.VizieR/J/ApJ/670/516
- Title:
- NGC 2547 4.5-8um photometry
- Short Name:
- J/ApJ/670/516
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have surveyed the 30Myr old cluster NGC 2547 for planetary debris disks using Spitzer. At 4.5-8um we are sensitive to the photospheric level down to mid-M stars (0.2M_{sun}_), and at 24um to early G stars (1.2M_{sun}_).
