- ID:
- ivo://CDS.VizieR/J/A+A/388/298
- Title:
- BV photometry of RT Lac
- Short Name:
- J/A+A/388/298
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Contemporaneous spectroscopic and photometric BV observations of the RS CVn type eclipsing binary RT Lacertae were performed in summer 2000. The photometric observations were obtained at the Ege University Observatory, while the spectroscopic ones were carried out at Catania Astrophysical Observatory in the spectral range 5860-6700{AA}. We obtained a high quality radial velocity curve of the system that allowed us to give more accurate values of the orbital parameters.
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- ID:
- ivo://CDS.VizieR/J/A+A/561/A106
- Title:
- BV photometry of 6 SMC stellar clusters
- Short Name:
- J/A+A/561/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar clusters in the Small Magellanic Cloud (SMC) are useful probes to study the chemical and dynamical evolution of this neighbouring dwarf galaxy, enabling inspection of a large period covering over 10Gyr. The main goals of this work are the derivation of age, metallicity, distance modulus, reddening, core radius and central density profile for six sample clusters, in order to place them in the context of the Small Cloud evolution. The studied clusters are: AM 3, HW 1, HW 34, HW 40, Lindsay 2, and Lindsay 3, where HW 1, HW 34, and Lindsay 2 are studied for the first time. Optical Colour-Magnitude Diagrams (V, B-V CMDs) and radial density profiles were built from images obtained with the 4.1m SOAR telescope, reaching V~23. The determination of structural parameters were carried out applying King profile fitting. The other parameters were derived in a self-consistent way by means of isochrone fitting, which uses the likelihood statistics to identify the synthetic CMDs that best reproduce the observed ones. Membership probabilities were determined comparing the cluster and control field CMDs. Completeness and photometric uncertainties were obtained performing artificial star tests. The results confirm that these clusters (except HW 34, identified as a field fluctuation) are intermediate-age clusters, with ages between 1.2Gyr (Lindsay 3) and ~5.0Gyr (HW 1). In particular HW 1, Lindsay 2, and Lindsay 3 are located in a region that we called West Halo, where studies on ages and metallicity gradients are still lacking. Moreover Lindsay 2 was identified as a moderately metal-poor cluster with [Fe/H]=-1.4+/-0.2dex, lower than expected from the age-metallicity relation by Pagel & Tautvaisiene (1998MNRAS.299..535P). We also found distances varying from ~53 to 66kpc, compatible with the large depth of the SMC.
- ID:
- ivo://CDS.VizieR/J/AcA/59/193
- Title:
- BV photometry of stars in NGC 6866
- Short Name:
- J/AcA/59/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 19 variable stars and two blue stragglers in the field of the open cluster NGC 6866. Three of the variable stars we classify as delta Sct, two as g Dor, four as WUMa, two as ellipsoidal variables, and one as an eclipsing binary. Seven stars show irregular variability. Two of the pulsators, delta Sct star NGC 6866-29 and gamma Dor star NGC 6866-21, are multiperiodic.
- ID:
- ivo://CDS.VizieR/J/AJ/131/407
- Title:
- BV photometry of stars in the LMC
- Short Name:
- J/AJ/131/407
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed a field in the disk of the LMC on two consecutive nights in search of rapid variable stars. We found two pulsating stars of type RRab and Scuti and four binary stars; among the latter we found one sdB or cataclysmic variable below the LMC blue main sequence and three very close binary systems on the main sequence.
- ID:
- ivo://CDS.VizieR/J/ApJ/549/578
- Title:
- BV photometry of Trumpler 14 and 16
- Short Name:
- J/ApJ/549/578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- H-R diagrams are presented for the very young galactic clusters Trumpler 14 and Trumpler 16, which are the two most populous clusters in the region of vigorous star formation surrounding {eta} Carinae. Point spread function photometry of UBV CCD images is presented down to V~19 for over 560 stars in Tr 16 and 290 stars in Tr 14. We have also obtained similar data for a local background field. After determining cluster membership through proper motions from a previous work, we find that the reddening of cluster members is significantly lower than that of the local background stars. Thus, we are able to use individual reddenings to identify likely members at far deeper levels than possible with proper motions. This work has revealed a significant population of pre-main-sequence (PMS) stars in both clusters. The location of the PMS stars in the H-R diagram indicates that the theoretical "stellar birthline" of Palla & Stahler (1990ApJ...360L..47P, follows the locus of stars far better than that of Beech & Mitalas (1994ApJS...95..517B). Comparison with both pre- and post-main-sequence isochrones also reveals that although intermediate-mass stars have been forming continuously over the last 10Myr, the high-mass stars formed within the last 3Myr. There is no evidence that the formation of the intermediate-mass stars was truncated by the formation of the high-mass stars.
- ID:
- ivo://CDS.VizieR/J/A+A/402/1033
- Title:
- BV photometry of UX Ari in 1987-2002
- Short Name:
- J/A+A/402/1033
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 14.3 years of previously unpublished photometric observations of UX Ari. The observations were obtained between 1987.9 and 2002.2 using the T3 0.4-metre Automatic Photoelectric Telescope at Fairborn Observatory and consist of 1228 B band and 1213 V band measurements. The comparison star was 62 Ari and the check star was 59 Ari. We have analyzed the new data together with previously published photometric observations. The V magnitude shows variations with dominant periods of about 12 and 25 years, where the longest period seems to correspond to an activity cycle. The previously reported anticorrelation between the B V colour and V magnitude variations is confirmed.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/1
- Title:
- BV photometry of variables in NGC 6397
- Short Name:
- J/A+AS/122/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 5 and 6 contain BV photometry of stars from NGC 6397 field which is presented in Figs. 1 and 2, respectively. File template.fits is a FITS format image of the surveyed field. Stars coordinates listed in the paper correspond to positions on this image.
- ID:
- ivo://CDS.VizieR/J/AJ/123/3216
- Title:
- BV photometry of variable stars in SMC
- Short Name:
- J/AJ/123/3216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B and V photometry has been obtained for variable stars in the northeast arm of the Small Magellanic Cloud (SMC). Periods and light curves have been determined for 237 periodic variables, including 201 Cepheids, 68 of which are newly discovered. Fundamental-mode Cepheids and first-overtone mode Cepheids are generally well separated in the BV color-magnitude diagram, with the latter having bluer mean colors than the former. The Cepheid period-color relationship for this outlying SMC field is indistinguishable from that seen in more centrally located SMC fields and is bluer than theoretical predictions. The red edge to the populated portion of the instability strip shifts to bluer colors for fainter Cepheids. There is support from our sample for a previously reported steepening in the slope of the period-luminosity relation for fundamental-mode Cepheids near a period of 2 days. The Cepheids of the northeast arm may be closer to us than are those of the main body of the SMC, but the difference is smaller than or equal to about 4kpc, comparable to the tidal radius of the SMC.
- ID:
- ivo://CDS.VizieR/J/A+A/362/223
- Title:
- 1984-1998 BV photometry of V815 Her
- Short Name:
- J/A+A/362/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a case study of the solar-stellar connection, we have analysed a prolonged time series of BV photometry of the chromospherically active binary V815 Her. The surface differential rotation in the rapidly rotating G5V primary caused changes of 4.6% in the seasonal photometric rotation periods. This would imply a differential rotation coefficient of k=0.184, if the rotation of the starspots follow the solar law of differential rotation and the activity is confined within the same latitudinal range as in the Sun, having k=0.189 and the spectral type G2V. Our analysis of the primary and secondary minima of the seasonal light curves indicated that the regions of stronger activity have concentrated on one active longitude, which has maintained a constant rotation period of 1.79244d for about 14 years. No regular activity cycle was detected in the mean brightness changes of V815 Her.
- ID:
- ivo://CDS.VizieR/J/AJ/152/120
- Title:
- BV photometry of V532 Mon
- Short Name:
- J/AJ/152/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first two sets of complete charge-coupled device light curves in the B and V bands of the short-period binary system, V532 Mon, are presented. The light curves are analyzed with spot models using the Wilson-Devinney code. V532 Mon is found to be an A-subtype intermediate-contact binary with a degree of contact factor of f=47.1%(+/-2.7%), a mass ratio of q=0.2502(+/-0.0019), and a cool spot on the primary component. The period changes of the system are investigated by combining newly determined times of light minimum with others published in the literature. We found that the general trend of the observed-calculated (O-C) curve shows a downward parabolic variation that corresponds to a long-term decrease in the orbital period at a rate of dP/dt=-1.716(+/-0.002)*10^-7^dyr^-1^. The long-term decrease of the orbital period can be explained by mass transfer from the more-massive component to the less massive one. The long-time period decrease, the intermediate-contact configuration, and the astrophysical parameters of the binary system suggest that V532 Mon will evolve into high fill-out, extreme mass-ratio overcontact binaries.
