- ID:
- ivo://CDS.VizieR/J/AJ/156/134
- Title:
- CCD measurements of multiple stars at ASV & NAOR
- Short Name:
- J/AJ/156/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of classical CCD observations for 371 double or multiple stars (450 pairs) obtained at both, Serbian Astronomical Station on the mountain of Vidojevica (ASV) and Bulgarian National Astronomical Observatory at Rozhen (NAOR) are presented. At ASV the observations were performed with the 0.6 m telescope in the first half of 2016 during 11 nights, and with the newly mounted 1.4 m telescope in the second half of 2016 during 16 nights. At NAOR, the observations were performed with the 2 m telescope during four nights. In this paper, we present 477 measurements (position angle and angular separation) for these 450 pairs. Among them there are 41 pairs with published orbital or linear elements and residuals are given for them. Some pairs have measurements for several epochs. Our observed pairs have angular separations in the interval from 1.60" to 190.30", with a mean angular separation of 14.87" and a median value of 4.34". Two new pairs and linear elements for four pairs which are calculated for the first time are also presented.
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- ID:
- ivo://CDS.VizieR/J/AJ/156/199
- Title:
- CCD observations in BVRI bands for TY Pup
- Short Name:
- J/AJ/156/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- TY Pup is a well-known bright eclipsing binary with an orbital period of 0.8192 days. New light curves in B, V, (RI)_C_ bands were obtained with the 0.61 m reflector robotic telescope (PROMPT-8) at CTIO in Chile during 2015 and 2017. By analyzing those photometric data with the W-D method, it is found that TY Pup is a low-mass-ratio (q~0.184) and deep-contact binary with a high fill-out factor (84.3%). An investigation of all available times of minimum light including three new ones obtained with the 60 cm and the 1.0 m telescopes at Yunnan Observatories in China indicates that the period change of TY Pup is complex. An upward parabolic variation in the O-C diagram is detected to be superimposed on a cyclic oscillation. The upward parabolic change reveals a long-term continuous increase in the orbital period at a rate of dP/dt=5.57(+/-0.08)x10^-8^ days/yr. The period increase can be explained by mass transfer from the less massive component (M_2_~0.3 M_{sun}_) to the more massive one (M_1_~1.65 M_{sun}_). The binary will be merging when it meets the criterion that the orbital angular momentum is less than three times the total spin angular momentum, i.e., J_orb_<3J_rot_. This suggests that the system will finally merge into a rapid-rotating single star and may produce a luminous red nova. The cyclic oscillation in the O-C diagram can be interpreted by the light-travel time effect via the presence of a third body.
- ID:
- ivo://CDS.VizieR/J/A+A/374/132
- Title:
- CCD photometry and astrometry of double stars
- Short Name:
- J/A+A/374/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new astrometric and photometric data for 253 visual double stars of the "intermediate" class, i.e. with angular separations in the range 1 to 15 arcsec. The multi-colour observations were obtained in 1992-94 as part of the ESO Key Programme "Visual Double Stars" performed at La Silla Observatory (Chile). Differential magnitudes and colours have been secured in a systematic way while component magnitudes and colour indices have been determined in the V and I passbands of the Cousins standard system in good photometric conditions only. Internal and mean external errors are respectively smaller than 0.01mag and a few hundred of a magnitude (0.02 to 0.03mag). Relative positions are obtained as a by-product with internal errors of the order of 0.006arcsec in angular separation and 0.08{deg} in position angle. Final accuracies are thoroughly discussed: we illustrate the overall excellent quality of the data and estimate the quality degradation for angular separations barely larger than the width of the seeing disk.
- ID:
- ivo://CDS.VizieR/J/A+AS/111/527
- Title:
- CCD photometry of 11 dwarf irregular galaxies
- Short Name:
- J/A+AS/111/527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD imaging and photometry in B and Cousins R of the dwarf irregular galaxies UGC 4459 (=DDO 53), UGC 5272 (A=DDO 64 and B), UGC 5340 (=DDO 68), UGC 6456, UGC 7559 (=DDO 126), UGC 8024 (=NGC 4789A=DDO 154), UGC 8091 (= GR 8=DDO 155), UGC 8320 (=DDO 168), UGC 8760 (=DDO 183), and DDO 210. For DDO 210 we also give results in the V filter. Photometry of the resolved stars was carried out on background-subtracted images using DAOPHOT. The tables of measurements include positions, magnitudes, colors, a magnitude error, and a color error. Integrated fluxes and colors are also reported. The single-star photometry is compared to previous results in three of the galaxies (UGC 8024, UGC 8091, DDO 210).
- ID:
- ivo://CDS.VizieR/J/ApJ/682/135
- Title:
- CCD photometry of M60
- Short Name:
- J/ApJ/682/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of the globular clusters (GCs) in the giant elliptical galaxy M60 in the Virgo Cluster, based on deep, relatively wide field Washington CT_1_ CCD images. The CMD reveals a significant population of GCs in M60 and a large number of young luminous clusters in NGC 4647, a small companion spiral northwest of M60. The color distribution of the GCs in M60 is clearly bimodal, with a blue peak at (C-T_1_)=1.37 and a red peak at (C-T_1_)=1.87. We derive two new transformation relations between the (C-T_1_)_0_ color and [Fe/H] using the data for the GCs in our Galaxy and M49. Using these relations, we derive the metallicity distribution of the GCs in M60, which is also bimodal: a dominant metal-poor component with center at [Fe/H]=-1.2, and a weaker metal-rich component with center at [Fe/H]=-0.2. We estimate the total number of the GCs in M60 to be 3600+/-500 and the specific frequency to be S_N_=3.8+/-0.4.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/39.39
- Title:
- CCD Photometry of NGC 2658, 2849, 3247
- Short Name:
- J/other/RMxAA/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry of the galactic open clusters NGC 2658, NGC 2849, and NGC 3247 is presented. For the first two clusters, BV(RI)_c data are given, and for NGC 3247 the data are BV(I)_c. The observations were carried out from the Complejo Astronomico El Leoncito (Argentina), and from Las Campanas (Chile). Each cluster was observed on two different nights; when possible, measurements for a given star were averaged. NGC 2658 observations were carried out from CASLEO on the nights of 8-9 January 1997 and 18-19 April 2001, in the BVRI filters. NGC 2849 data in the BVRI filters were obtained at Las Campanas on the night 10-11 April 1996, and at CASLEO on 19-20 April 2001. NGC 3247 was observed at CASLEO on the nights 16-17 January 1996 (BV) and 1-2 April 1998 (BVI). The given star coordinates are relative to the corresponding cluster center.
- ID:
- ivo://CDS.VizieR/J/AJ/106/181
- Title:
- CCD photometry of open cluster M67
- Short Name:
- J/AJ/106/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a CCD photometric survey of the central one-half degree of the old open cluster, M67, in U, B, V, and I colors to magnitude V=20. Extensive comparison of our photometry with other published datasets shows excellent agreement, indicating that CCD photometry is capable of producing a uniform set of measurements consistent with the photometric system defined primarily by the Landolt standard sequence. The color-magnitude diagram of the cluster shows a well-defined main sequence extending at least to the limit of the photometry at M(V)=10.55 and a substantial binary sequence. At least 38 percent of cluster stars are binaries. The observations were performed on 3 nights on 15-18 February 1990 with the 1.09m telescope at Kitt Peak National Observatory with a Tektronix 512^2^ CCD camera; a standard KPNO UBVRI filter set was used, with BVR filters being the Harris et, and I the "nearly Mould" filter.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/2122
- Title:
- CCD photometry of star clusters in the LMC
- Short Name:
- J/MNRAS/450/2122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Washington system colour-magnitude diagrams (CMDs) for 17 practically unstudied star clusters located in the bar as well as in the inner disc and outer regions of the Large Magellanic Cloud (LMC). Cluster sizes were estimated from star counts distributed throughout the entire observed fields. Based on the best fits of theoretical isochrones to the cleaned (C-T_1_, T_1_) CMDs, as well as on the {delta}T_1_ parameter and the standard giant branch method, we derive ages and metallicities for the cluster sample. Four objects are found to be intermediate-age clusters (1.8-2.5 Gyr), with [Fe/H] ranging from -0.66 to -0.84. With the exception of SL 263, a very young cluster (~16 Myr), the remaining 12 objects are aged between 0.32 and 0.89 Gyr, with their [Fe/H] values ranging from -0.19 to -0.50. We combined our results with those for other 231 clusters studied in a similar way using the Washington system. The resulting age-metallicity relationship shows a significant dispersion in metallicities, whatever age is considered. Although there seems to exist a clear tendency for the younger clusters to be more metal rich than the intermediate ones, we believe that none of the chemical evolution models currently available in the literature reasonably well represents the recent chemical enrichment processes in the LMC clusters. The present sample of 17 clusters is part of our ongoing project of generating a data base of LMC clusters homogeneously studied using the Washington photometric system and applying the same analysis procedure.
- ID:
- ivo://CDS.VizieR/J/AJ/144/149
- Title:
- CCD photometry of the W UMa type TY Boo
- Short Name:
- J/AJ/144/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD four-color light curves of TY Boo made on eight nights over 2010-2011 were analyzed in comparison with historical light curves obtained from 1969 through 2011. The light curves could all be represented by a unique geometry and by wavelength consistent photometric parameters of a two-spot model on either stellar component. It is confirmed that TY Boo is a shallow W-type contact binary system with a degree of contact factor of f=7.6%(+/-0.8). A period investigation based on all available data shows a long-term decrease (dP/dt=-3.65x10^-8^days/yr) and an oscillation (P_3_=58.9yr, A=0.0254days). Without ruling out the presence of a tertiary companion, the weight of evidence points to an active cyclic magnetic activity that causes spot formation rather than an unseen companion. Mass transfer between the components and angular momentum loss are also considered as possible mechanisms.
- ID:
- ivo://CDS.VizieR/J/AJ/143/30
- Title:
- CCD photometry of V380 Cas
- Short Name:
- J/AJ/143/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first multicolor CCD photometry for the eclipsing binary V380 Cassiopeia (V380 Cas) observed on 34 nights in 2009 and 2010 at the University of Patras Observatory. The PHOEBE program based on the Wilson-Devinney algorithm was used to analyze the first complete BVRcIc light curves. It was found that V380 Cas was misclassified and it is a well-detached system consisting of two main-sequence stars. A range of solutions found to give satisfactory fits to the observations is also investigated. The first orbital solution based on the photometric mass ratio q=1.08 of almost equal temperatures and masses and orbital inclination of i=86.57{deg} was obtained. In addition, based on all available times of light minima, including 12 new ones, a new orbital period of P=2.714539884 days is given.
