- ID:
- ivo://CDS.VizieR/J/AJ/144/167
- Title:
- Photometry and spectroscopy of CF Tauri
- Short Name:
- J/AJ/144/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CF Tau is now known to be an eclipsing triple star with relatively deep total and annular eclipses. New light and radial velocity curves as well as new times of minima were obtained and used for further modeling of the system. Very accurate (better than 0.9%) masses and radii of the eclipsing pair are determined from analysis of the two new light curves, the radial velocity curve, and the times of minimum light. The mass and luminosity of the distant third component is accurately determined as well. Theoretical models of the detached, evolved eclipsing pair match the observed absolute properties of the stars at an age of about 4.3Gyr and [Fe/H]=-0.14.
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- ID:
- ivo://CDS.VizieR/J/AJ/147/7
- Title:
- Photometry and spectroscopy of NGC 6520
- Short Name:
- J/AJ/147/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use CCD and photoelectric photometry with Stromgren filters along with medium resolution spectra to investigate NGC 6520, an open cluster very nearly in the direction of the galactic center. We find an age of 60Myr, a distance of 2kpc, and an average reddening E(b-y)=0.295, which increases toward the south. The average heliocentric radial velocity of the B stars is -29km/s, while the velocity of the nearby Barnard 86 is about 0 (heliocentric; -11km/s compared to the LSR). This velocity difference amounts to about 1.8kpc since the cluster formed, implying that it is extremely doubtful NGC6520 is related to Barnard 86.
- ID:
- ivo://CDS.VizieR/J/AJ/101/1699
- Title:
- Photometry in globular cluster NGC 6229
- Short Name:
- J/AJ/101/1699
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD-based BV photometry for over 1100 stars in and around the globular cluster NGC 6229. For the first time, the cluster's entire giant branch and its horizontal branch are delineated, from which metallicity ([Fe/H]~-1.4) and distance (d__{sun}_~28kpc; d_GC_~27kpc) estimates ensue. NGC 6229 is found to have a relatively blue horizontal branch for its intermediate metallicity, which is unusual for an outer halo cluster. Its low R value (defined as N_HB_/N_RG_) hints that the blue color of its horizontal branch is due to a lower than average helium abundance. Three possible new variable stars are identified, including one RR Lyrae and two long-period variables. We present a brief review of our knowledge of basic data for the 13 globular clusters lying more than 24 kpc from the Galactic center. The unusually red horizontal branch phenomenon is common only among the outermost clusters. An average R value for these clusters suggests the effect is not caused by an overabundance of helium. The Oosterhoff dichotomy apparently persists into the outer halo, although the number of clusters with RR Lyrae variables is small.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1640
- Title:
- Photometry of candidate RR Lyrae stars in the SDSS
- Short Name:
- J/AJ/130/1640
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present unfiltered CCD photometry of a sample of 71 candidate RR Lyrae stars during 2003 and 2004, out of 148 candidate stars that were selected from Sloan Digital Sky Survey (SDSS) commissioning data by Ivezic and coworkers (2000AJ....120..963I). We obtain light curves of 69 candidate stars and present a catalog of their positions, amplitudes, periods, types, and mean magnitudes. We confirm that the 69 stars are true RR Lyrae variables based on periods and light curves, for the first time for 41 of them. We identify 57 type ab, 11 type c, and 1 type d (double-mode) in our sample. The double-mode RR Lyrae star shows properties similar to globular cluster stars and are unlike field stars of the Galactic halo in the Petersen diagram.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/53.235
- Title:
- Photometry of 6 deep-contact W UMa
- Short Name:
- J/other/RMxAA/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations in Sloan g' and i' bands of W UMa binaries V0637 Peg, V0473 Cam, CSS J153314.8+560527, CSS J075258.0+382035, V0416 Gem and NSVS 6859986 are presented. Their periods are in the range of 0.26-0.43d. The light curve solutions revealed that the components of each target are almost equal in temperature. The stellar components are of G and K spectral types and undergo total eclipses. All targets have deep-contact configurations with fillout factor f>=0.5. NSVS 6859986 has one o f the biggest value determined until now, f=0.84. We studied the empirical dependencies of fillout factor on the stellar parameters (temperature, period, mass ratio, relative component radii, and luminosity ratio) for a sample of around thirty stars. They are consistent with the theoretical predictions but there are deviations from the common trends.
- ID:
- ivo://CDS.VizieR/J/AJ/121/148
- Title:
- Photometry of Dorado Group Dwarf Galaxies
- Short Name:
- J/AJ/121/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V and I CCD photometry of suspected low surface brightness dwarf galaxies detected in a survey covering ~2.4 deg^2^ around the central region of the Dorado group of galaxies. The low surface brightness galaxies were chosen based on their sizes and magnitudes at the limiting isophote of 26V{mu}. The selected galaxies have magnitudes brighter than V~20 (MV~-11 for an assumed distance to the group of 17.2 Mpc), with central surface brightnesses {mu}_0_>22.5 Vmag.arcsec^-2^, scale lengths h>2", and diameters >=14" at the limiting isophote. Using these criteria, we identified 69 dwarf galaxy candidates. Four of them are large very low surface brightness galaxies that were detected on a smoothed image, after masking high surface brightness objects. Monte Carlo simulations performed to estimate completeness, photometric uncertainties and to evaluate our ability to detect extended low surface brightness galaxies show that the completeness fraction is, on average, >80% for dwarf galaxies with -17<MV<-10.5 and 22.5<{mu}_0_<25.5 Vmag.arcsec^-2^, for the range of sizes considered by us (D>=14"). The V-I colors of the dwarf candidates vary from -0.3 to 2.3 with a peak on V-I=0.98, suggesting a range of different stellar populations in these galaxies. The projected surface density of the dwarf galaxies shows a concentration toward the group center similar in extent to that found around five X-ray groups and the elliptical galaxy NGC 1132 studied by Mulchaey & Zabludoff (1999ApJ...514..133M), suggesting that the dwarf galaxies in Dorado are probably physically associated with the overall potential well of the group.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A131
- Title:
- Photometry of 8 main belt asteroids
- Short Name:
- J/A+A/545/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The shapes and spin states of asteroids observed with photometric techniques can be reconstructed using the lightcurve inversion method. The resultant models can then be confirmed or exploited further by other techniques, such as adaptive optics, radar, thermal infrared, stellar occultations, or space probe imaging. During our ongoing work to increase the set of asteroids with known spin and shape parameters, there appeared a need for displaying the model plane-of-sky orientations for specific epochs to compare models from different techniques. It would also be instructive to be able to track how the complex lightcurves are produced by various asteroid shapes.
- ID:
- ivo://CDS.VizieR/J/AJ/149/150
- Title:
- Photometry of multiples at NAOR and ASV in 2012
- Short Name:
- J/AJ/149/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 246 double or multiple stars were carried out during six nights in 2012. This is the seventh series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2012, using the 0.6m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 117 double or multiple stars were carried out during five nights. This is the second series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper we present the results for the position angle and angular separation for 453 pairs and residuals for 105 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.50'' to 178.12'', with a median angular separation of 8.13''. We also present the recalculated linear solution for one pair and three linear solutions that have been calculated for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/153/195
- Title:
- Photometry of multiple stars at NAOR&ASV in 2015
- Short Name:
- J/AJ/153/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of CCD observations of 154 double or multiple stars, made with the 2 m telescope of the Bulgarian National Astronomical Observatory at Rozhen over five nights in 2015, are presented. This is the ninth series of measurements of CCD frames obtained at Rozhen. We also present results of CCD observations of 323 double or multiple stars made with the 0.6 m telescope of the Serbian Astronomical Station on the mountain of Vidojevica over 23 nights in 2015. This is the fourth series of measurements of CCD frames obtained at this station. This paper contains the results for the position angle and angular separation for 801 pairs and residuals for 127 pairs with published orbital elements or linear solutions. The angular separations are in the range from 1.52" to 201.56", with a median angular separation of 8.26". We also present eight pairs that are measured for the first time and linear elements for five pairs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/252/357
- Title:
- Photometry of NGC 6171
- Short Name:
- J/MNRAS/252/357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- B and V CCD photometry is presented for 1565 stars in the low-concentration globular cluster NGC6171=M107
