- ID:
- ivo://CDS.VizieR/J/A+A/410/879
- Title:
- VRI CCD photometry of NGC 2126
- Short Name:
- J/A+A/410/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first CCD photometric observations of the northern open cluster NGC 2126. Data were taken on eight nights in February and December 2002 with a total time span of ~57 hours. Almost 1000 individual V-band frames were examined to find short-period variable stars. We discovered six new variable stars, of which one is a promising candidate for an eclipsing binary with a pulsating component. Here we present single-epoch colours and magnitudes for ~800 stars in the field and the light curve data for the six variables. Note that the coordinates in ngc2126.dat are not particularly accurate because of the applied crude astrometry (errors up to +/-1-2arcsec are quite likely close to the edge). For variable star identification, consult table3.dat.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/417/745
- Title:
- V(RI)C differential photometry of V861 Her
- Short Name:
- J/A+A/417/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- First Cousins V(RI)_C_ light curves of the W UMa-type eclipsing variable star V861 Herculis are presented. The system was observed in 2000 and 2003. The light curves obtained at different epochs showed significant deviation from each other. The O'Connell effect (usually explained by spots on the surface which are responsible for variations in the intensity of the system) was about {Delta}V=0.05mag in 2000 but it vanished in 2003 (except the night of February 22/23, 2003 when we observed a small O'Connell effect ({Delta}V=0.020)). Further peculiarities of the light curves are also discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/132/960
- Title:
- V(RI)c light-curves of EQ Tauri
- Short Name:
- J/AJ/132/960
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New V, R_C_, and I_C_ light curves of EQ Tau have been obtained in 2002 and 2003. These show the secondary minimum to be a total eclipse. These new light curves have been analyzed, together with the published radial velocity observations, using the Wilson-Devinney code. The binary has an overcontact configuration, with an orbital inclination of 85{deg}, a difference in component temperature of 80K, and an overcontact fill-out factor of 16%. Absolute parameters of the component stars have been determined: M1=1.28M_{sun}_, R1=1.17R_{sun}_, L1=1.39 L_{sun}_, and M2=0.47M_{sun}_, R2=0.81R_{sun}_, L2=0.63L_{sun}_. The calculated distance is 180+/-20pc. A critical review of our new timings of minimum light together with previously published ones suggests a change from one constant period to another one around 1974 rather than a cyclical variation. When corrected for energy transfer in the common envelope, the physical parameters of the two components are in good agreement with those of unevolved single stars of similar masses.
- ID:
- ivo://CDS.VizieR/J/A+A/343/446
- Title:
- VRI Cousins photometry of Am stars
- Short Name:
- J/A+A/343/446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tablea1 contains photoelectric VRI Cousins photometry for 63 Am stars observed on the 17th June, 1996 with the 1.52m telescope of the Observatorio Astronomico Nacional (O.A.N.) at Calar Alto (Almeria, Spain), and on the 25th and 26th of the same month using the 1m Jakobus Kapteyn telescope at the Observatorio del Roque de los Muchachos (O.R.M., Canary Islands, Spain). The reduction procedure followed is explained in Rossello et al. (1985A&AS...59..399R) and Landolt (1983, Cat. <II/118>; 1983AJ.....88..853L) standard stars were used. We provide the V magnitude, the (V-R) and (V-I) colour indices, their associated standard errors and the number of observations performed for each star.
- ID:
- ivo://CDS.VizieR/J/PASP/111/812
- Title:
- V(RI)C Phot of Cepheids in the Magellanic Clouds
- Short Name:
- J/PASP/111/812
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present V(RI)C data for 13 Cepheids in the Large Magellanic Cloud and eight in the Small Magellanic Cloud. The total number of new measures is 55 in each wavelength band. The median uncertainty in the photometry is 0.03 mag. These results supplement a larger photometric program presented in the second paper in this series which contained 1000 measures (0.01 mag) in each wavelength band on 22 variables with periods in the range 8133 days.
- ID:
- ivo://CDS.VizieR/J/MNRAS/405/1711
- Title:
- VRIg'i' photometry of 7 M15 giants
- Short Name:
- J/MNRAS/405/1711
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a search for long-period variable (LPV) stars among giant branch stars in M15 which, at [Fe/H]~-2.3, is one of the most metal-poor Galactic globular clusters. We use multicolour optical photometry from the 0.6-m Keele Thornton and 2-m Liverpool Telescopes. Variability of {delta}V~0.15mag is detected in K757 and K825 over unusually long time-scales of nearly a year, making them the most metal-poor LPVs found in a Galactic globular cluster. K825 is placed on the long secondary period sequence, identified for metal-rich LPVs, though no primary period is detectable. We discuss this variability in the context of dust production and stellar evolution at low metallicity, using additional spectra from the 6.5-m Magellan (Las Campanas) telescope. A lack of dust production, despite the presence of gaseous mass loss raises questions about the production of dust and the intracluster medium of this cluster.
- ID:
- ivo://CDS.VizieR/J/AJ/135/441
- Title:
- VRIH{alpha} photometry in NGC 2264
- Short Name:
- J/AJ/135/441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed deep wide-field CCD photometry of the young open cluster NGC 2264 to study the extent of star-forming regions (SFRs) and the shape of the initial mass function. In this paper, we present VRI and H{alpha} photometry for more than 67,000 stars. From the spatial distribution of the selected H{alpha} emission stars, we identify two active SFRs and a less active halo region surrounding these two SFRs. There are several H{alpha} emission stars in the field region outside the halo region, and these may be newly formed stars in the Mon OB1 association surrounding the cluster. The locus of pre-main-sequence (PMS) stars in the I_C_ versus V-I_C_ diagram is revised from the distribution of H{alpha} and X-ray emission stars in the diagram.
- ID:
- ivo://CDS.VizieR/J/MNRAS/370/954
- Title:
- VRIHalpha photometry of M34
- Short Name:
- J/MNRAS/370/954
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of a V- and i-band time-series photometric survey of M34 (NGC 1039) using the Wide Field Camera (WFC) on the Isaac Newton Telescope (INT), achieving better than 1 per cent precision per data point for 13~<i~<17. Candidate cluster members were selected from a V versus VI colour-magnitude diagram over 14<V<24 (0.12<M/M_{sun}_<1.0), finding 714 candidates, of which we expect ~400 to be real cluster members (taking into account contamination from the field). The mass function was computed, and found to be consistent with a lognormal distribution in dN/dlogM. Searching for periodic variable objects in the candidate members gave 105 detections over the mass range 0.25<M/M_{sun}_<1.0. The distribution of rotation periods for 0.4<M/M_{sun}_<1.0 was found to peak at ~7d, with a tail of fast rotators down to periods of ~0.8d. For 0.25<M/M_{sun}_<0.4 we found a peak at short periods, with a lack of slow rotators (e.g. P>5d), consistent with the work of other authors at very low masses. Our results are interpreted in the context of previous work, finding that we reproduce the same general features in the rotational period distributions. A number of rapid rotators were found with velocities ~ a factor of 2 lower than in the Pleiades, consistent with models of angular momentum evolution assuming solid body rotation without needing to invoke core-envelope decoupling.
- ID:
- ivo://CDS.VizieR/J/A+A/430/1005
- Title:
- VRIH{alpha} photometry of NGC 2264 variables
- Short Name:
- J/A+A/430/1005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 lists 405 periodic variable stars we found in the area of NGC 2264 between. It contains information of the position, brightness, colours, and period of these stars. It also lists the spectral type taken from the literature (if available) as well as the alternative identification numbers of the stars which we used in the analysis process. The results presented here are based on a photometric monitoring program of a 34'x34' field in NGC 2264 carried out with the Wide-Field-Imager (WFI) attached to the ESO/MPG 2.2m telescope on La Silla, Chile. Observations were obtained on 44 nights in the I_C_ band during a period of two months between Dec. 2000 and March 2001. We also obtained several additional images through V, R_C_ and H{alpha} filters.
- ID:
- ivo://CDS.VizieR/J/AJ/159/135
- Title:
- VRIJHK LCs of the binary T Tauri star V582 Mon
- Short Name:
- J/AJ/159/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The binary T Tauri star V582Mon (KH15D) is surrounded by a tilted and nodally precessing ring of dusty material, which has caused periodic occultations of one or both stars over the last 50 years. Here, we present multi-color time-series photometry (VRIJHK) throughout the 2017/2018 observing season, when the ring was covering the entire orbit of star A and gradually exposing the orbit of star B. We calculate the mean apparent magnitude of star B to be I=14.08. Besides the periodic eclipses of star B due to its orbital motion, we observed unexpected dips in brightness indicative of partially transparent stellar-sized clumps within the ring. The wavelength dependence of these events is suggestive of extinction by dust grains significantly larger than typical interstellar dust grains. The photometric variability observed while star B is being uncovered by the trailing edge of the ring is not simply the time reversal of the behavior seen when star A was being covered by the leading edge. Whereas the leading edge appeared to be very sharply defined, the trailing edge is "clumpy" and "fuzzy" (transparent), with a more gradual transition in opacity. The clumpiness and transparency of the occulting material provide a unique opportunity to study the properties of dust grains in a likely planet-forming zone.
