- ID:
- ivo://CDS.VizieR/J/MNRAS/371/1301
- Title:
- BVI photometry of six old open clusters
- Short Name:
- J/MNRAS/371/1301
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the first BVI CCD photometry of six overlooked old open clusters (Berkeley 44, NGC 6827, Berkeley 52, Berkeley 56, Skiff 1 and Berkeley 5) and derive estimates of their fundamental parameters by using isochrones from the Padova library. We found that all the clusters are older than the Hyades, with ages ranging from 0.8Gyr (NGC 6827 and Berkeley 5) to 4.0Gyr (Berkeley 56). The latter is one of the old open clusters with the largest heliocentric distance.
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- ID:
- ivo://CDS.VizieR/J/A+AS/121/455
- Title:
- BVI photometry of stars in Berkeley 18
- Short Name:
- J/A+AS/121/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD BVI photometry for Berkeley 18, a rich open cluster located in the Galactic anticenter. The cluster age is similar to, or marginally lower than age of M 67. Its distance is estimated at 5.8kpc and the reddening E(B-V) is probably higher than 0.46. Our data indicate that Be 18 is one of the most populous objects in the whole sample of known galactic open clusters. The angular diameter of the cluster is estimated at 26arcmin, which corresponds to a linear size of about 44pc. The horizontal branch of Be 18 exhibits a large width in comparison with other old open clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/L32
- Title:
- BVI photometry of the SMC star cluster ESO 51-SC09
- Short Name:
- J/ApJ/756/L32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results on the age and metallicity estimates of the astonishingly unstudied Small Magellanic Cloud (SMC) cluster (ESO 51-SC09), from CCD BVI photometry obtained at the ESO NTT with the EMMI attached. ESO 51-SC09 turns out to be a relatively small cluster (FWHM=10+/-1pc) located ~4{deg} northward from the galaxy center. We report for the first time a mean cluster age of 7.0+/-1.3Gyr and a mean cluster metallicity of [Fe/H]=-1.00+/-0.15 dex, concluding that ESO 51-SC09 belongs to the group of the oldest SMC clusters. We found that the cluster is projected onto an older (age~10-13Gyr) and more metal-poor ([Fe/H]=-1.3+/-0.2 dex) dominant field stellar population, so that the cluster could have reached its current location because of its orbital motion.
- ID:
- ivo://CDS.VizieR/J/ApJ/881/22
- Title:
- BVI photometry of the TypeII SN KSP-SN-2016kf
- Short Name:
- J/ApJ/881/22
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present the discovery and the photometric and spectroscopic study of H-rich Type II supernova (SN) KSP-SN-2016kf (SN2017it) observed in the KMTNet Supernova Program in the outskirts of a small irregular galaxy at z~0.043 within a day of the explosion. Our high-cadence, multi-color (BVI) light curves of the SN show that it has a very long rise time (t_rise_~20days in the V band), a moderately luminous peak (M_V_~-17.6mag), a notably luminous and flat plateau (M_V_~-17.4mag and decay slope s~0.53mag per 100 days), and an exceptionally bright radioactive tail. Using the color-dependent bolometric correction to the light curves, we estimate the ^56^Ni mass powering the observed radioactive tail to be 0.10{+/-}0.01M_{sun}_, making it an H-rich Type II SN with one of the largest ^56^Ni masses observed to date. The results of our hydrodynamic simulations of the light curves constrain the mass and radius of the progenitor at the explosion to be ~15M_{sun}_ (evolved from a star with an initial mass of ~18.8M_{sun}_) and ~1040R_{sun}_, respectively, with the SN explosion energy of ~1.3x10^51^erg. The above-average mass of the KSP-SN-2016kf progenitor, together with its low metallicity of Z/Z_{sun}_~0.1--0.4 obtained from spectroscopic analysis, is indicative of a link between the explosion of high-mass red supergiants and their low-metallicity environment. The early part of the observed light curves shows the presence of excess emission above what is predicted in model calculations, suggesting there is interaction between the ejecta and circumstellar material. We further discuss the implications of the high initial mass of the progenitor and the low-metallicity environment of KSP-SN-2016kf for our understanding of the origin of Type II SNe.
- ID:
- ivo://CDS.VizieR/J/A+A/388/179
- Title:
- BVI photometry of two open clusters
- Short Name:
- J/A+A/388/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of CCD BVI Johnson-Cousins photometry down to V~19mag in the regions of the unstudied stellar groups Pismis 23 and BH 222, both projected close to the direction towards the Galactic centre. We measured V magnitude and B-V and V-I colours for a total of 928 stars in fields of about 4'x4'.
- ID:
- ivo://CDS.VizieR/J/A+A/315/348
- Title:
- BVI photometry of two Orion galaxies
- Short Name:
- J/A+A/315/348
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two relatively faint (B=15.7 and B=18.4mag, respectively), low velocity (+276 and +322km/s) galaxies were imaged with a CCD in the B, V, I bands at the prime focus of the 6m telescope on 16 October 1993. By means of the brightest stars we estimated their distances to be 6.4 and 5.5(+/-2)Mpc, assuming a galactic extinction of 2.7 and 2.9mag, respectively. We note that these isolated irregular dwarfs are located to a high Supergalactic latitude, -63deg, and their low radial velocities may be the result of a retarded expansion along the polar axis of the Local cloud of galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/121/870
- Title:
- BVI photometry of Variables in M33
- Short Name:
- J/AJ/121/870
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The DIRECT project aims to determine direct distances to two important galaxies in the cosmological distance ladder - M31 and M33 - using detached eclipsing binaries (DEBs) and Cepheids. We present the results of the first large-scale CCD-based search for variables in M33. We have observed two fields located in the central region of M33 for a total of 95 nights on the F. L. Whipple Observatory 1.2 m telescope and 36 nights on the Michigan-Dartmouth-MIT 1.3 m telescope. We have found a total of 544 variables, including 251 Cepheids and 47 eclipsing binaries. The catalog of variables is available on-line, along with finding charts and BVI light curve data (consisting of 8.2x10^4^ individual measurements). The complete set of CCD frames is available upon request.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2400
- Title:
- BVI photometry of V728 Her
- Short Name:
- J/AJ/110/2400
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The W UMa system V728 Her has been observed photometrically in B, V, and I_c passbands at the RAO over five seasons and spectroscopically at DAO over three seasons to obtain radial velocities. New times of minima are provided and a period analysis confirms previous ephemerides. The light and radial velocity curves were analyzed with the latest University of Calgary enhancements to the Wilson-Devinney program and new solutions found. The best model is that involving a contact system with convective atmospheres. In probing the best solution possible, use was made of the enhanced reflection and second-order limb-darkening calculations available in the 1993 version of the WD program. The mass ratio is found to be 0.1786+/-0.0023. The contact parameter is found to be f=0.71+/-0.11. The masses are determined to be 1.654+/-0.037M_{sun}_ and 0.295+/-0.009M_{sun}_ and the radii are 1.784+/-0.015R_{sun}_ and 0.867+/-0.054R_{sun}_, respectively. The determined temperature difference, T2-T1 is 165+/-19K, and the luminosities for components 1 and 2 are 5.5+/-0.5L_{sun}_ and 1.4+/-0.3L_{sun}_, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/466/181
- Title:
- BVI photometry of Whiting 1
- Short Name:
- J/A+A/466/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recently Carraro (2005ApJ...621L..61C) drew attention to the remarkable star cluster Whiting 1, showing that it lies at about 40kpc from the Sun and is therefore unquestionably a member of the Galactic halo (l=-60.6{deg}). Its Color Magnitude Diagram (CMD) indicated that Whiting 1 is very young (~5Gyrs) for a globular cluster. It is highly likely that Whiting 1 is originated in a dwarf galaxy that has since been disrupted by the Milky Way. The main purpose of the present study is to better constrain the properties of Whiting 1, and assess whether it belongs to a stellar stream from the Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph). Deep CCD photometry in the BVI pass-band obtained with the VLT is used to improve the quality of the CMD, and provide more solid estimates of the cluster distance and age, while high resolution spectra of three evolved stars obtained at Magellan is used to derive the cluster kinematics and analyze its possible membership to the Sgr dSph. We demonstrate that - independently on the Halo model employed - Whiting 1 is part of the trailing stream of the Sgr dSph. We derive a new age estimate of 6.5^+1.0^_-0.5_Gyr, and a smaller heliocentric distance of 29.4^+1.8^_-2.0_kpc. The number of globular clusters confirmed to be members of Sgr dSph is now 6. Among these clusters, Whiting 1 is particularly interesting, being the youngest and one of the most metal rich. The existence of Whiting 1 shows how the Sgr dSph was able to form star clusters for a period at least of 6Gyr.
- ID:
- ivo://CDS.VizieR/J/A+A/360/529
- Title:
- BVI photometry of 4 young open clusters
- Short Name:
- J/A+A/360/529
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD observations in the B, V, and I passbands obtained for stars in the fields of the open clusters Pismis 22, NGC 6178, NGC 6216, and Ruprecht 130, projected not far from the Galactic centre (|l|<30{deg}, |b|<2{deg}). The sample consists of about 790 stars reaching down to V~18-19mag. From the analysis of the colour magnitude diagrams, we confirmed the physical reality of the clusters and derived their reddening, distance and age. In addition, we obtained flux-calibrated integrated spectra in the range 3500-9200{AA} for the cluster sample. The equivalent widths of the Balmer lines provided us with age estimates, while the comparison with template spectra allowed us to derive both foreground reddening and age. The photometric and spectroscopic results reveal that the four studied objects are young open clusters with ages ranging between 35 and 50Myr. The clusters, located between 1.0kpc and 4.3kpc from the Sun, are affected by different amounts of interstellar visual absorption (0.6=~A_v_=~6.0).
