- ID:
- ivo://CDS.VizieR/J/AJ/123/1528
- Title:
- UBV(RI)_C_ and JHK photometry in NGC 2264
- Short Name:
- J/AJ/123/1528
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an optical and near-infrared study of a 45'x45' field in NGC 2264, which includes both S Mon and the Cone Nebula. We report photometry at optical (UBVR_C_I_C_) and near-infrared (JHK) wavelengths for ~600 stars and spectroscopic classifications for ~400 of these stars. We identify circumstellar disk candidates using three techniques: excess ultraviolet (U-V) emission, excess near-IR (I-K and H-K) emission, and H{alpha} emission-line equivalent widths for those stars with spectra. We find generally good correlation between disk indicators thought to originate from different physical processes. We find little if any evolution of disk fraction with stellar age or mass. However, when we derive mass accretion rates (dM/dt) from the excess emission at U, we find that dM/dt decreases with age over the age range spanned by our data, ~0.15 Myr, and increases with mass over the range ~0.25-1M_{sun}_. These findings are comparable to results found previously by us in the Orion Nebula cluster flanking fields.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/118/2894
- Title:
- UBVRI CCD photometry in NGC 188
- Short Name:
- J/AJ/118/2894
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-precision UBVRI CCD photometry of the old open cluster NGC 188. Our color-magnitude diagram extends from near the red giant branch tip to as faint as ~5mag below the main-sequence turnoff. From an analysis of these data along with published photometry for M67, we draw the following conclusions: (1) From the UBV two-color diagram, we find a reddening of E(B-V)=0.04+/-0.02 for M67 and E(B-V)=0.09+/-0.02 for NGC 188. (2) Based on main-sequence fitting to solar abundance isochrones, the distance moduli turn out to be (m-M)v=9.69+/-0.11 for M67 and (m-M)v=11.44+/-0.08 for NGC 188. (3) The comparison of the CMDs to theoretical isochrones indicates that an amount of core convective overshoot equivalent to 0.10 of a pressure scale height is appropriate for M67, while no overshoot is required to fit the CMD of NGC 188. These isochrones suggest that NGC 188 is 3.0+/-0.7 Gyr older than M67. (4) There is a clear indication of mass segregation in both M67 and NGC 188, with the most massive stars (M/M_{sun}_>1.1) being more centrally concentrated than those that are the least massive (0.8>=M/M_{sun}_>0.65).
- ID:
- ivo://CDS.VizieR/J/AJ/147/139
- Title:
- UBVRI CCD photometry of open clusters. II. NGC 6866
- Short Name:
- J/AJ/147/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a maximum-likelihood procedure to fit theoretical isochrones to the observed cluster color-magnitude diagrams of NGC6866, an open cluster in the Kepler spacecraft field of view. The Markov chain Monte Carlo algorithm permits exploration of the entire parameter space of a set of isochrones to find both the best solution and the statistical uncertainties. For clusters in the age range of NGC6866 with few, if any, red giant members, a purely photometric determination of the cluster properties is not well-constrained. Nevertheless, based on our UBVRI photometry alone, we have derived the distance, reddening, age, and metallicity of the cluster and established estimates for the binary nature and membership probability of individual stars. We derive the following values for the cluster properties: (m-M)_V_=10.98+/-0.24, E(B-V)=0.16+/-0.04 (so the distance=1250pc), age=705+/-170Myr, and Z=0.014+/-0.005.
- ID:
- ivo://CDS.VizieR/J/AJ/145/7
- Title:
- UBVRI CCD photometry of the open cluster NGC 6811
- Short Name:
- J/AJ/145/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 6811 is one of the four open clusters located in the Kepler spacecraft field of view. We obtained UBVRI photometry of the cluster on six nights (four of them photometric) with the 1.08m Hall and 1.83m Perkins telescopes at Lowell Observatory. The mean photometric precision ranges from better than 0.01mag in the V, B-V, V-R, and V-I indices among stars brighter than magnitude 15 to about 0.05mag for U-B at magnitude 18. We followed a Bayesian statistical approach using the Markov Chain Monte Carlo algorithm to determine the cluster reddening, distance, age, and iron content from a maximum-likelihood fit to stellar isochrones. Using the Yale-Yonsei isochrones, we derived E(B-V)=0.066+/-0.025, (m-M)_V_=10.13+/-0.19, age=1.06+/-0.19Gyr, and Z=0.012+/-0.004 ([Fe/H]=-0.18); with the Padova isochrones, we found E(B-V)=0.081+/-0.015, (m-M)_V_=10.31+/-0.11, age=0.94+/-0.08Gyr, and Z=0.012+/-0.002 ([Fe/H]=-0.20). The uncertainties include possible errors in the photometric zero points of +/-0.01mag, but do not include uncertainties in the models. Taking into account the differences between the two sets of models, we find the best estimate for the cluster parameters to be E(B-V)=0.074+/-0.024, (m-M)_V_=10.22+/-0.18, age=1.00+/-0.17Gyr, and Z=0.012+/-0.004 ([Fe/H]=-0.19).
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/1441
- Title:
- UBV(RI)cJHK photometry of NGC 2401
- Short Name:
- J/MNRAS/367/1441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on a deep optical CCD (UBV(RI)_C) photometric survey and on the Two-Micron All-Sky-Survey (2MASS, <II/246>) data we derived the main parameters of the open cluster NGC 2401. We found this cluster is placed at 6.3+/-0.5kpc (Vo-Mv=14.0+/-0.2) from the Sun and is 25Myr old, what allows us to identify NGC 2401 as a member of the young population belonging to the innermost side of the extension of the Norma-Cygnus spiral-arm in the Third Galactic Quadrant. A spectroscopic study of the emission star LSS 440 that lies in the cluster area revealed it is a B0Ve star; however, we could not confirm it is a cluster member. We also constructed the cluster luminosity function (LF) down to V~22 and the cluster initial mass function (IMF) for all stars with masses above M~1-2M_{sun}_. It was found that the slope of the cluster IMF is x~1.8+/-0.2. The presence of a probable PMS star population associated to the cluster is weakly revealed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/415/1355
- Title:
- UBV(RI)c photometry of NGC 4852
- Short Name:
- J/MNRAS/415/1355
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The southern open cluster NGC 4852 was re-observed in the UBVRI passbands to refine its intrinsic fundamental parameters. An extended spectral coverage was also undertaken aimed at obtaining a clear picture of the kind of stars inhabiting the cluster upper main sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/417/961
- Title:
- UBV(RI)c photometry of NGC 2580 and NGC 2588
- Short Name:
- J/A+A/417/961
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD broad band photometric observations in the fields of the Third Galactic Quadrant open clusters NGC 2580 and NGC 2588 (V(I)c and UBV(RI)c respectively). From the analysis of our data we found that NGC 2580 is located at a distance of about 4kpc and its age is close to 160Myr. As for NGC 2588, it is placed at about 5kpc from the Sun and is 450Myr old. This means that NGC 2588 belongs to the extension of the Perseus arm, whereas NGC 2580 is closer to the local arm structure. The luminosity functions (LFs) have been constructed for both clusters down to V~20 together with their initial mass functions (IMFs) for stars with masses above M~1-1.5M_{sun}_. The IMF slopes for the most massive bins yielded values of x~1.3 for NGC 2580 and x~2 for NGC 2588. In the case of this latter cluster we found evidence of a core-corona structure produced probably by dynamical effect. In the main sequences of both clusters we detected gaps, which we suggest could be real features.
- ID:
- ivo://CDS.VizieR/J/A+A/445/493
- Title:
- UBV(RI)c photometry of NGC 2425 and NGC 2635
- Short Name:
- J/A+A/445/493
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse CCD broad band (UBV(RI)c) photometric data obtained in the fields of the poorly studied open clusters NGC 2425 and NGC 2635. Both clusters are found to be of intermediate age thus increasing the population of open clusters known to be of the age of, or older than, the Hyades. More explicitly, we find that NGC 2425 is a 2.2Gyr old cluster, probably of solar metallicity, located at 3.5kpc from the Sun. NGC 2635 is a Hyades age (600Myr) cluster located at a distance of 4.0kpc from the Sun. Its Colour Magnitude Diagram reveals that it is extremely metal poor for its age and position, thus making it a very interesting object in the context of Galactic Disk chemical evolution models.
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/1102
- Title:
- UBV(RI)c photometry of 6 open clusters
- Short Name:
- J/MNRAS/429/1102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRcIc CCD photometry in the fields of six Galactic open clusters toward the Perseus spiral arm. These data, complemented with J, H and Ks magnitudes from 2MASS, have been used to determine the following ages, distances and colour excesses E(B-V) for these clusters: 40Myr, 3180_-380_^+440^pc, 0.54+/-0.03mag (Berkeley 96); 250Myr, 2410_-200_^+220^pc, 0.77+/-0.06mag (Berkeley 97); 70Myr, 2490_-170_^+180^pc, 0.51+/-0.05mag (King 12); 160Myr, 2830_-150_^+160^pc, 0.88+/-0.09mag (NGC 7261); 280Myr, 2450_-170_^+190^pc, 0.24+/-0.03mag (NGC 7296); 160Myr, 2750_-210_^+220^pc, 0.49+/-0.02mag (NGC 7788). We found gaps in the mass function of clusters Be 97, King 12 and NGC 7788 in the mass intervals [1.3-1.5], [1.4-1.6] and [1.5-1.7] solar masses, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/453/101
- Title:
- UBV(RI)c photometry of 4 open clusters
- Short Name:
- J/A+A/453/101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ages derived from the low mass stars still contracting onto the main sequence often differ from ages derived from the high mass ones that have already evolved away from it. We investigate the general claim of disagreement between these two independent age determinations by representing UBVRI photometry of the young galactic open clusters NGC 2232, NGC 2516, NGC 2547 and NGC 4755, spanning the age range ~10-150Myr.
