- 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/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/A+A/330/990
- Title:
- VRIJHK photometry of the Serpens cloud core
- Short Name:
- J/A+A/330/990
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a deep optical (VRI) and near infrared (JHK) survey of the central part of the Serpens molecular cloud. A total of 138 sources were detected in the 19 arcmin^2^ surveyed area down to a limiting magnitude of 16.3 in K. We find that the form of the observed K Luminosity Function (KLF) of stars belonging to the Serpens Molecular cloud is consistent with that predicted from a Miller & Scalo (1979ApJS...41..513M) Interstellar Mass Function (IMF). We have investigated the KLF evolution with the age of a cluster by modeling KLFs of hypothetical clusters. Our results suggest that two phases of star formation could have taken place in the Serpens core.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/262
- Title:
- VRI photometry and theta values in open clusters
- Short Name:
- J/ApJS/176/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, new Cousins VRI data are presented for NGC 752 and Praesepe, and new and extant data are combined into an augmented database for M67. For those three clusters, catalogs containing Cousins VRI photometry, reddening-corrected values of (V-K)J, and temperatures are produced. The same is done for Coma by using both previously published and newly derived Cousins photometry. An extant set of catalogs for the Hyades is updated to include V magnitudes and values of (R-I)C that were published after the original catalogs appeared. Finally, M67 V magnitudes published previously by Sandquist are corrected for an effect that depends on location on the face of the cluster. The corrected data and values of (V-I)C given by Sandquist are then set out in a supplementary catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/149/200
- Title:
- VRI photometry in NGC 7129
- Short Name:
- J/AJ/149/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC7129 is a bright reflection nebula located in the molecular cloud complex near l=105.4{deg}, b=+9.9{deg}, about 1.15kpc distant. Embedded within the reflection nebula is a young cluster dominated by a compact grouping of four early-type stars: BD+65{deg}1638 (B3V), BD+65{deg}1637 (B3e), SVS 13 (B5e), and LkH{alpha} 234 (B8e). About 80 H{alpha} emission sources brighter than V~23 are identified in the region, many of which are presumably T Tauri star members of the cluster. We also present deep (V~23), optical (VR_C_I_C_) photometry of a field centered on the reflection nebula and spectral types for more than 130 sources determined from low dispersion, optical spectroscopy. The narrow pre-main sequence evident in the color-magnitude diagram suggests that star formation was rapid and coeval. A median age of about 1.8Myr is inferred for the H{alpha} and literature-identified X-ray emission sources having established spectral types, using pre-main sequence evolutionary models. Our interpretation of the structure of the molecular cloud and the distribution of young stellar objects is that BD+65{deg}1638 is primarily responsible for evacuating the blister-like cavity within the molecular cloud. LkH{alpha} 234 and several embedded sources evident in near-infrared adaptive optics imaging have formed recently within the ridge of compressed molecular gas. The compact cluster of low-mass stars formed concurrently with the early-type members, concentrated within a central radius of ~0.7pc. Star formation is simultaneously occurring in a semi-circular arc some ~3pc in radius that outlines remaining dense regions of molecular gas. High dispersion, optical spectra are presented for BD+65{deg}1638, BD+65{deg}1637, SVS 13, LkH{alpha} 234, and V350 Cep. These spectra are discussed in the context of the circumstellar environments inferred for these stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/546/1006
- Title:
- VRI photometry of M35
- Short Name:
- J/ApJ/546/1006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present very deep and accurate photometry of the open cluster M35. We have observed this association in the Cousins R, I filters, together with the Johnson V filter. We have covered a region of 27.5x27.5 square arcmin, equivalent to a fifth of the total area of the cluster. The data range from I_c_=12.5 to 23.5mag, and the color intervals are 0.4<=(V-I)_c_<=3.0, 0.5<=(R-I)_c_<=2.5. Roughly, these values span from 1.6M_{sun}_ down to the substellar limit, in the case of cluster members. By using the location of the stars on color-magnitude and color-color diagrams, we have selected candidate members of this cluster. We have merged our sample with previously published data and obtained a color-magnitude diagram for the complete stellar population of the cluster, covering the spectral range early B-mid M. Based on the distribution of field and cluster stars in color-magnitude and color-color diagrams, we estimate that two-thirds of these candidates are likely to be true members of M35. These stars approximately double the number of stars identified as candidate members of this cluster (~2700). We provide the photometry and accurate positions of these stars.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2228
- Title:
- VRI photometry of PMS stars in NGC 2264 OB
- Short Name:
- J/AJ/127/2228
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We summarize the results of an observing campaign to identify periodic pre-main-sequence (PMS) variables in the NGC 2264 OB association. We find 201 periodic candidates.
- ID:
- ivo://CDS.VizieR/J/AJ/152/129
- Title:
- VR photometry for 914 stars in NGC 188
- Short Name:
- J/AJ/152/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used the newly commissioned 50cm Binocular Network telescope at Qinghai Station of Purple Mountain Observatory (Chinese Academy of Sciences) to observe the old open cluster NGC188 in V and R as part of a search for variable objects. Our time-series data span a total of 36 days. Radial velocity and proper-motion selection resulted in a sample of 532 genuine cluster members. Isochrone fitting was applied to the cleaned cluster sequence, yielding a distance modulus of (m-M)_V_^0^=11.35+/-0.10mag and a total foreground reddening of E(V-R)=0.062+/-0.002mag. Light-curve solutions were obtained for eight W Ursae Majoris eclipsing binary systems (W UMas), and their orbital parameters were estimated. Using the latter parameters, we estimate a distance to the W UMas that is independent of the host cluster's physical properties. Based on combined fits to six of the W UMas (EP Cep, EQ Cep, ES Cep, V369 Cep, and-for the first time-V370 Cep and V782 Cep), we obtain an average distance modulus of (m-M)_V_^0^=11.31+/-0.08mag, which is comparable to that resulting from our isochrone fits. These six W UMas exhibit an obvious period-luminosity relation. We derive more accurate physical parameters for the W UMa systems and discuss their initial masses and ages. The former show that these W UMa systems have likely undergone angular momentum evolution within a convective envelope (W-type evolution). The ages of the W UMa systems agree well with the cluster's age.