- ID:
- ivo://CDS.VizieR/J/BaltA/19/35
- Title:
- NGC 752 Vilnius photometry
- Short Name:
- J/BaltA/19/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of CCD photometry in the seven-color Vilnius system of 3058 stars down to V~18.0mag in a 1.5 square degree field around the cluster NGC752 are presented. For most of the stars brighter than V=17.0mag, photometric spectral and luminosity classes are determined. The catalog of 1174 stars down to V=15.5mag is given in the paper. The entire catalog will be available at the CDS Simbad database. The color-magnitude diagram indicates an extension of the cluster's main sequence down to 5mag below the turnoff point.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1628
- Title:
- NGC 7142 Vilnius photometry
- Short Name:
- J/MNRAS/437/1628
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of medium-band photometry of 1037 stars in the area of the old open cluster NGC 7142 down to V=20.1mag in the Vilnius seven-colour system are presented. Photometric results are used to classify in spectral and luminosity classes about 80 per cent of stars down to V=18.5mag, to identify cluster members, to determine the main cluster parameters and to investigate the interstellar extinction in this direction. The average extinction A_V_ of the cluster is about 1.1mag [E(B-V)=0.35], and its distance is 2.3kpc (the distance modulus 11.8mag). The age of the cluster, 3.0Gyr, is estimated from the intrinsic colour-magnitude diagram with individual dereddening of each star and the Padova isochrones. The surface distribution of the extinction is shown. The reddening of the eclipsing variable V375 Cep is found to be close to the average reddening of the cluster. Probably, the cluster contains five red clump giants, two asymptotic branch stars and four blue stragglers.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/1848
- Title:
- NGC 7129 Vilnius photometry
- Short Name:
- J/MNRAS/438/1848
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dust cloud TGU H645 P2 and embedded in it the young open cluster NGC 7129 are investigated using the results of medium-band photometry of 159 stars in the Vilnius seven-colour system down to V=18.8mag. The photometric data were used to classify about 50 per cent of the measured stars in spectral and luminosity classes. The extinction A_V_ versus distance diagram for the 20'x20' area is plotted for 155 stars with two-dimensional classification from the present and the previous catalogues. The extinction values are found in the range between 0.6 and 3.4mag. However, some red giants, located in the direction of the dense parts of the cloud, exhibit the infrared extinction equivalent up to A_V_=13mag. The distance to the cloud (and the cluster) is found to be 1.15kpc (the true distance modulus 10.30mag). For determining the age of NGC 7129, a luminosity versus temperature diagram for six cluster members of spectral classes B3-A1 was compared with the Pisa pre-main-sequence evolution tracks and the Palla birthlines. The cluster can be as old as about 3Myr, but star formation continues till now as witnessed by the presence in the cloud of many younger pre-main-sequence objects identified with photometry from 2MASS, Spitzer and WISE infrared surveys.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1684
- Title:
- NGC 2264: VRIH{alpha} photometry
- Short Name:
- J/AJ/128/1684
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The young open cluster NGC 2264 was observed on 2002 January 67 with the CFH12K mosaic CCD on the 3.6m Canada-France-Hawaii Telescope to investigate the shape of the initial mass function (IMF). In order to select the pre-main-sequence (PMS) members more completely, Chandra X-Ray Observatory archival data were retrieved and used for the identification of X-ray-emitting weak-line T Tauri stars. In addition, the (R-I, V-I) diagram was used to exclude background late-type giants, and a statistical approach was applied to estimate the number of contaminating foreground main-sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A78
- Title:
- NGC2264 weak-line T Tauri lithium abundances
- Short Name:
- J/A+A/590/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of lithium abundance in cool dwarfs provides a unique probe of non-standard processes in stellar evolution. Aims. We investigate here the lithium content of young low-mass stars in the 5 Myr-old star forming region NGC 2264 and its relationship with rotation. We combine lithium equivalent width measurements (EW(Li)) from the Gaia-ESO Survey with the determination of rotational periods from the CSI 2264 survey. We consider only bona fide non accreting cluster members in order to minimize uncertainties on EW(Li). We report the existence of a relationship between lithium content and rotation in NGC 2264 at an age of 5Myr. The Li-rotation connection is seen over a restricted temperature range (Teff=800-4400K) where fast rotators are Li-rich compared to slow ones. This correlation is similar to, albeit of lower amplitude than, the Li-rotation connection previously reported for K dwarfs in the 125Myr-old Pleiades cluster. We investigate whether the non-standard pre-main sequence models developed so far to explain the Pleiades results, which are based on episodic accretion, pre-main sequence core-envelope decoupling, and/or radius inflation due to enhanced magnetic activity, can account for an early development of the Li-rotation connection. While radius inflation appears to be the most promising possibility, each of these models has issues. We therefore also discuss external causes that might operate during the first few Myr of pre-main sequence evolution, such as planet engulfment and/or steady disk accretion, as possible candidates for the common origin for Li-excess and fast rotation in young low-mass pre-main sequence stars.
- ID:
- ivo://CDS.VizieR/J/A+A/312/818
- Title:
- NGC 2516 X-ray sources
- Short Name:
- J/A+A/312/818
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ROSAT PSPC detector was used to obtain a deep pointing with its center on the young open cluster NGC 2516 and total integration time of 9284 sec. Altogether 64 X-ray sources were detected showing strong concentration towards the optical cluster centre. This suggests that most of the sources are actually associated with NGC 2516. 42 of these sources could be identified with optical stars in the field of the cluster; after correction for a mean offset between optical and nominal ROSAT positions of about 13", optical star and X-ray source positions are found to agree, on the average, within about 9", while maximum observed positional differences amount to 27". X-ray sources identified with optical cluster stars include HR 3147 (=HD 66194; B2.5IVe), the visually brightest B star in the cluster, three close visual late B-type binaries (h 4027 A,B, h 4031 A,B, and I 1104 A,B) with projected separations ranging between about 4x10^16^cm and 6x10^16^cm, as well as several (six) chemically peculiar Bp/Ap(Si) and Ap(SrCrEu) stars.
- ID:
- ivo://CDS.VizieR/J/AJ/132/2296
- Title:
- NICMOS observations of Mon R2 cluster
- Short Name:
- J/AJ/132/2296
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed Hubble Space Telescope NICMOS2 F110W-, F160W-, F165M-, and F207M-band images covering the central 1'x1' region of the cluster associated with Mon R2 in order to constrain the initial mass function (IMF) down to 20M_J_. The flux ratio between the F165M and F160W bands was used to measure the strength of the water-band absorption feature and select a sample of 12 out of the total sample of 181 objects that have effective temperatures between 2700 and 3300K.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1665
- Title:
- NICMOS observations of NGC 2024
- Short Name:
- J/AJ/126/1665
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of NICMOS observations of the embedded cluster associated with NGC 2024. An analysis of the cluster color-magnitude diagram (CMD) using the models of D'Antona & Mazzitelli and Baraffe et al. (published in 1997MmSAI..68..807D and 1998, Cat. <J/A+A/337/403>, respectively) indicates that the ratio of intermediate-mass (1.0-10.0M_{sun}_) to low-mass (0.1-1.0M_{sun}_) stars is consistent with the stellar initial mass function (IMF) for the field. In addition to the CMD analysis, we present results on the multiplicity of stars in the region. Three companions (in a sample of 95 potential primaries) were found, with angular separations between 0.4" and 1.0", translating to a projected linear separation of 184-460AU for an estimated distance of 460pc. The completeness of binary detections is assessed using recovery fractions calculated by a series of tests using artificially generated companions to potential primaries in the data frames. We find that the binary fraction in NGC 2024 is consistent with that of Duquennoy & Mayor (published in 1991A&A...248..485D) for solar neighborhood stars over the range of separations and companion masses appropriate for our survey.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A22
- Title:
- Nine new open clusters within 500pc from the Sun
- Short Name:
- J/A+A/595/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the results of the Milky Way Star Clusters (MWSC) survey was the detection of a slight under-density of old (ca. 1Gyr) clusters within the nearest kilo-parsec from the Sun. This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal such clusters. We derived proper motions from a combination of Tycho-2 with URAT1, and obtained a mean precision of about 1.4mas/yr per co-ordinate for 1.3 million stars north of -20{deg} declination. We cut the sky into narrow proper motion slices and searched for spatial over-densities of stars in each slice. We then examined stars from over-densities in optical and near-infrared colour-magnitude diagrams to determine if they are compatible with isochrones of a cluster. We estimated the field star contamination using our data and the Besancon Galactic model. We detected nine hitherto unknown open clusters in the vicinity of the Sun with ages between 70Myr and 1Gyr, and distances between 200 and 500pc.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A39
- Title:
- NIR photometry in 10 nearby spiral galaxies
- Short Name:
- J/A+A/542/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spiral structure is a prominent feature in many disk galaxies and is often outlined by bright, young objects. We study the distribution of young stellar clusters in grand-design spiral galaxies and thereby determine whether strong spiral perturbations can influence star formation.
