- ID:
- ivo://CDS.VizieR/J/A+A/554/A3
- Title:
- Vilnius photometry of IC1805 stars
- Short Name:
- J/A+A/554/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of CCD photometry in the Vilnius seven-color system down to V=18mag are presented for 242 stars in the direction of the young open cluster IC 1805 that is located in the active star-forming region W4 in the Cas OB6 association. Photometric data were used to classify stars into spectral and luminosity classes, and to determine their interstellar reddenings, extinctions and distances.
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Search Results
- ID:
- ivo://CDS.VizieR/J/BaltA/22/181
- Title:
- Vilnius photometry of M29 (NGC6913)
- Short Name:
- J/BaltA/22/181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnitudes and color indices in the Vilnius seven-color system were determined for 1752 stars down to V = 19.5 mag in the direction of the open cluster M29 (NGC 6913). The region is centered at RA=20:24, DEC=+38:30 (J2000) and covers an area of 1.5 sq. deg. The photometric data are used to classify about 70% of stars in spectral and luminosity classes and peculiarity types.
- ID:
- ivo://CDS.VizieR/J/BaltA/14/179
- Title:
- Vilnius photometry of NGC 1647 area
- Short Name:
- J/BaltA/14/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The area of the open cluster NGC 1647 in Taurus is investigated by CCD photometry in the Vilnius seven-color system. Magnitudes and color indices are determined for 433 stars down to V=15.0mag in the 45arcmin diameter area. For 252 of them photometric spectral and luminosity classes, interstellar reddenings, extinctions and distances are obtained. According to the CDS WEBDA database, 89 of them have a high cluster membership probability. Their mean distance from the Sun is 555+/-74pc, excluding four stars which seem to be field stars. The main sequence starts at spectral class B7 V which corresponds to a cluster age of about 150 million years. Cluster members show a differential interstellar extinction ranging from 0.8 to 1.8mag. The mean extinction of the cluster stars is 1.12+/-0.25mag. Interstellar extinction in the area is dominated by the Taurus dark cloud complex at 160pc. Color excesses of individual stars correlate well with the 100um dust thermal emission intensity. The cluster shape is investigated by counting stars down to K=15.6mag and is found to be elongated in the direction roughly perpendicular to the Milky Way, with the flattening 0.4.
- ID:
- ivo://CDS.VizieR/J/ApJS/186/191
- Title:
- VI photometry and spectroscopy in h+{chi} Per
- Short Name:
- J/ApJS/186/191
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From photometric observations of ~47000 stars and spectroscopy of ~11000 stars, we describe the first extensive study of the stellar population of the famous Double Cluster, h and {chi} Persei, down to subsolar masses. By analyzing optical spectra and optical/infrared photometry, we constrain the distance moduli (dM), reddening (E(B-V)), and ages for h Persei, {chi} Persei, and the low-density halo population surrounding both cluster cores. With the exception of mass and spatial distribution, the clusters are nearly identical in every measurable way. From these data, we establish the first spectroscopic and photometric membership lists of cluster stars down to early/mid M dwarfs. At minimum, there are ~5000 members within 10' of the cluster centers, while the entire h and {chi} Persei region has at least ~13000 and as many as 20000 members. The Double Cluster contains ~8400M_{sun}_ of stars within 10' of the cluster centers. We estimate a total mass of at least 20000M_{sun}_. We conclude our study by outlining outstanding questions regarding the past and present properties of h and {chi} Persei. From comparing recent work, we compile a list of intrinsic colors and derive a new effective temperature scale for O-M dwarfs, giants, and supergiants.
1285. VI photometry in NGC 188
- ID:
- ivo://CDS.VizieR/J/A+A/390/961
- Title:
- VI photometry in NGC 188
- Short Name:
- J/A+A/390/961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used HST-WFPC2 to study the white dwarf luminosity function of the old open cluster NGC 188 in order to determine a lower limit to the age of the cluster (~5Gyr) by looking at the faint end of the cooling sequence (down to V~26.5).
- ID:
- ivo://CDS.VizieR/J/A+A/390/931
- Title:
- VI photometry in Pismis 23 and Stephenson 2
- Short Name:
- J/A+A/390/931
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pismis 23 and Stephenson 2 are two very reddened open clusters, projected close to the Galactic plane. We present VI and JH photometry for Pismis 23 and I and Gunn z for Stephenson 2. We derive a relatively old age of ~700Myr for Pismis 23, with a reddening value of E(B-V)=1.73 and a distance d_{sun}_~2.6kpc from the Sun. Stephenson 2 has a clump of red supergiants, indicating a young age of about 20Myr, somewhat younger and more distant (d_{sun}_~6kpc) than recently reported in the literature. The age estimate for such a young object is crucial for the distance estimate. The high reddening of these two clusters relative to predictions from the diffuse interstellar medium at their distances is due to discrete intervening clouds.
- ID:
- ivo://CDS.VizieR/J/A+AS/121/451
- Title:
- VI photometry of Berkeley 66
- Short Name:
- J/A+AS/121/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A colour magnitude diagram (CMD) extending to V=~19mag is given for 444 stars in the region of the galactic cluster Berkeley 66. The V and I photometry of a nearby field is also reported. This object appears very faint, highly contaminated by foreground stars and very reddened. The apparent distance modulus (m-M) and the colour excess E_V-I_ are guessed to be 17.5 and 1.1, respectively, with an uncertainty of at least 30%. Adopting these values the comparison of the CMD with theoretical isochrones from the Padova group provides an age around 1.0Gyr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/346/1143
- Title:
- VI photometry of Collinder 121
- Short Name:
- J/MNRAS/346/1143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a VI photometric catalogue towards the open cluster Cr 121. XMM-Newton and ROSAT data are used to discover a low-mass pre-main sequence (PMS) along this sightline. de Zeeuw et al. (1999, Cat. <J/AJ/117/354>) have identified Cr 121 as a moving group, using Hipparcos data, at a distance of 592pc; we reject the scenario that these low-mass PMS stars are associated with that association. By considering the higher mass main sequence stellar membership of the groups along this sightline, the density of low-mass PMS stars and their age spread we argue that the low-mass PMS stars are associated with a young, compact cluster at a distance of 1050pc.
- ID:
- ivo://CDS.VizieR/J/AJ/115/592
- Title:
- VI photometry of NGC 2157
- Short Name:
- J/AJ/115/592
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out Wide Field Planetary Camera 2 V- and I-band imaging of the young LMC cluster NGC 2157. Construction of a color-magnitude diagram and isochrone fitting yield an age of {tau}=10^8^yr, a reddening E(B-V)=0.1, and a distance modulus of 18.4mag. Our data cover the mass range 0.75M_{sun}_<=m<=5.1M_{sun}_. We find that the cluster mass function changes significantly from the inner regions to the outer regions, becoming steeper (larger number of low-mass stars relative to high-mass stars) at larger radii. The age of NGC 2157 is comparable to its two-body relaxation timescale only in the cluster core. The observed steepening of the mass function at larger radii is therefore most likely an initial condition of the cluster stars. Such initial conditions are predicted in models of cluster star formation in which dissipative processes act more strongly upon more massive stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/116/263
- Title:
- VI photometry of open clusters
- Short Name:
- J/ApJS/116/263
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD VI photometric data for 10 template open clusters with accurately determined fundamental parameters are presented. From the observed V versus V-I diagrams of the clusters, fiducial sequences have been defined and transformed into the M_v_ versus (V-I)_0_ diagram by averaging sequences of template open clusters with similar ages. The resulting composite Mv versus (V-I)_0_ diagram presents a homogeneous set of empirical isochrones in the age range between 5Myr and 4Gyr. These empirical isochrones show an overall very good agreement with those computed from stellar evolutionary models. Theoretical isochrones with moderate overshooting fit the observed main sequences better than the canonical ones for clusters older than 600Myr. The present set of empirical isochrones will be useful for the study of faint reddened open clusters