- ID:
- ivo://CDS.VizieR/J/MNRAS/306/361
- Title:
- UBVI CCD photometry of M35 (NGC 2168)
- Short Name:
- J/MNRAS/306/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- UBVI CCD photometry has been obtained for the intermediate-age open cluster M35 (NGC 2168). From this new photometry we derived the cluster parameters (Vo-MV= 9.60+/-0.10 mag, E(B-V) = 0.255+/-0.024 mag), age (logAge=8.3+/-0.3) and a photometric abundance (Z~0.008, i.e. [Fe/H]~-0.3) from comparison with theoretical isochrones of the Padova group. A minimum binary frequency (35+/-5%) was estimated from the distribution of distance moduli of unevolved proper motion members. Faint photometric members were selected by using differences in the reddening effect on colour indices.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/123/290
- Title:
- UBVI CCD photometry of NGC 2516
- Short Name:
- J/AJ/123/290
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVI CCD photometry of the intermediate-age open cluster NGC 2516.
- ID:
- ivo://CDS.VizieR/J/AJ/145/46
- Title:
- UBVIc photometry in Westerlund 1
- Short Name:
- J/AJ/145/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Westerlund 1 is the most important starburst cluster in the Galaxy due to its massive star content. We have performed BVI_C_ and JK_S_ photometry to investigate the initial mass function (IMF). By comparing the observed color with the spectral-type-intrinsic-color relation, we obtain the mean interstellar reddening of <E(B-V)>=4.19+/-0.23 and <E(J-K_S_)>=1.70+/-0.21. Due to the heavy extinction toward the cluster, the zero-age main sequence fitting method based on optical photometry proved to be inappropriate for the distance determination, while the near-infrared photometry gave a reliable distance to the cluster, 3.8kpc from the empirical relation. Using the recent theoretical stellar evolution models with rotation, the age of the cluster is estimated to be 5.0+/-1.0Myr. We derived the IMF in the massive part and obtained a fairly shallow slope of {Gamma}=-0.8+/-0.1. The integration of the IMF gave a total mass for the cluster in excess of 5.0x10^4^M_{sun}_. The IMF shows a clear radial variation indicating the presence of mass segregation. We also discuss the possible star formation history of Westerlund 1 from the presence of red supergiants and relatively low luminosity yellow hypergiants.
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/1241
- Title:
- UBVIc photometry of cluster Berkeley 59
- Short Name:
- J/MNRAS/383/1241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVIc CCD photometry of the young open cluster Be 59 with the aim to study the star formation scenario in the cluster. The radial extent of the cluster is found to be ~10arcmin (2.9pc). The interstellar extinction in the cluster region varies between E(B-V)=1.4 to 1.8mag. The ratio of total-to-selective extinction in the cluster region is estimated as 3.7+/-0.3. The distance of the cluster is found to be 1.00+/-0.05kpc. Using near-infrared (NIR) colours and slitless spectroscopy, we have identified young stellar objects (YSOs) in the open cluster Be 59 region. The Midcourse Space Experiment (MSX) and IRAS-HIRES images around the cluster region are also used to study the emission from unidentified infrared bands and to estimate the spatial distribution of optical depth of warm and cold interstellar dust.
- ID:
- ivo://CDS.VizieR/J/A+A/419/149
- Title:
- UBV(I)c photometry of NGC 6996
- Short Name:
- J/A+A/419/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and discuss broad band CCD UBV(I)c photometry and low resolution spectroscopy for stars in the region of the open cluster NGC 6996, located in the North America Nebula. The new data allow us to tightly constrain the basic properties of this object. We revise the cluster size, which in the past has been significantly underestimated. The width of the Main Sequence is mainly interpreted in terms of differential reddening, and indeed the stars' color excess E(B-V) ranges from 0.43 to 0.65, implying the presence of a significant and evenly distributed dust component. We cross-correlate our optical photometry with near infrared photometry from 2MASS, and by means of spectral classification we are able to build extinction curves for an handful of bright members. We find that the reddening slope and the total to selective absorption ratio Rv toward NGC 6996 are anomalous. Moreover the reddening-corrected colors and magnitudes allow us to derive estimates for the cluster distance and age, which turn out to be 760+/-70pc (V0-MV=9.4+/-0.2) and ~350Myr, respectively. Based on our results, we suggest that NGC 6996 is located in front of the North America Nebula, and does not seem to have any apparent relationship with it.
- ID:
- ivo://CDS.VizieR/J/A+A/436/527
- Title:
- UBVIc photometry of NGC 4852
- Short Name:
- J/A+A/436/527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide-field deep UBVIc photometry for the previously unstudied open cluster NGC 4852 down to a limiting magnitude Ic~24, obtained from observations taken with the Wide Field Imager camera on-board the MPG/ESO 2.2m telescope at La Silla (ESO, Chile), in the photometric night of July 7, 2002. These data are used to obtain the first estimate of the cluster basic parameters, to study the cluster spatial extension by means of star counts, and to derive the Luminosity (LF) and Mass Functions (MF). The cluster radius turns out to be 5.0+/-1.0arcmin. The cluster emerges clearly from the field down to V=20mag. At fainter magnitudes, it is completely confused with the general Galactic disk field. The stars inside this region define a young open cluster (200 million years old) 1.1kpc far from the Sun (m-M=11.60, E(B-V)=0.45). The Present Day Mass Functions (PDMF) from the V photometry is one of the most extended in mass obtained to date, and can be represented as a power-law with a slope alpha=2.3+/-0.3 and (the Salpeter MF in this notation has a slope alpha=2.35), in the mass range 3.2<=m/m_{sun}_<=0.6. Below this mass, the MF cannot be considered as representative of the cluster MF, as the cluster merges with the field and therefore the MF is the result of the combined effect of strong irregularities in the stellar background and interaction of the cluster with the dense Galactic field. The cluster total mass at the limiting magnitude results to be 2570+/-210M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AN/325/307
- Title:
- UBVIc photometry of NGC 3077 center
- Short Name:
- J/AN/325/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVIc photometry of starlike objects in the central region of NGC 3077. The colour-colour and colour-magnitude diagrams of the objects are discussed. Many of the objects under consideration, starlike from the ground, are probably dense young star clusters (super star clusters, SSC). Ages spreading over ~4 to ~150Myr are estimated for most of these objects. Sakai and Madore (2001ApJ...555..280S) found enhanced star formation ~30-125Myr ago also in the halo of this galaxy; thus, high star forming activity has occurred within the entire galaxy (centre and halo) since ~130..150Myr. Having ended in the outer regions about 30Myr ago, it is going on near the centre with full vigour.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A125
- Title:
- UBVI data of open cluster Trumpler 27
- Short Name:
- J/A+A/548/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spiral structure of the Milky Way inside the solar circle is still poorly known because of the high density of the material that causes strong extinction towards the Galactic center. We present results of the first extensive and deep color-color diagram (CCD) photometric survey carried out in the field of the open cluster Trumpler 27, an object immersed in a region of extremely high visual absorption in the constellation of Sagittarius not far from the Galaxy center. The survey covers almost a quarter of square degree. We look for young stars clumps that might plausibly be associated with spiral structure. Wide-field UBVI photometry combined with infrared information allows us to reconstruct the distribution in the reddening and distance of young stars in the field using the CCD and color-magnitude diagrams (CMD).
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/454
- Title:
- UBVIH{alpha} photometry in NGC 1893
- Short Name:
- J/MNRAS/443/454
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a UBVI and H{alpha} photometric study of the young open cluster NGC 1893 in the HII region W8 (IC 410 or Sh 2-236). A total of 65 early-type members are selected from photometric diagrams. A mean reddening of the stars is <E(B-V)>=0.563+/-0.083mag. The published photometric data in the near- and mid-infrared passbands are used to test the reddening law towards the cluster, and we confirm that the reddening law is normal (R_V_=3.1). Zero-age main-sequence fitting gives a distance modulus of V_0_-M_V_= 12.7+/-0.2mag, equivalent to 3.5+/-0.3kpc. From H{alpha} photometry, 125 H{alpha} emission stars and candidates are identified as pre-main-sequence (PMS). The lists of young stellar objects and X-ray sources published by previous studies allow us to select a large number of PMS members down to 1M_{sun}_. Isochrone fitting in the Hertzsprung-Russell diagram gives a turn-off age of 1.5Myr and the median age of 1.9Myr from the PMS members with a spread of ~5Myr. We derive the initial mass function (IMF) for stars with mass larger than 1M_{sun}_. The slope of the IMF ({Gamma}=-1.3+/-0.1) is well consistent with the Salpeter/Kroupa IMF. A total mass of the cluster appears to be in excess of 1300M_{sun}_. Finally, we estimate the mass accretion rate of 82 PMS members in the mass range of 0.6-5M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/1451
- Title:
- UBVIH{alpha} photometry of IC 1848
- Short Name:
- J/MNRAS/438/1451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IC 1848 is one of the young open clusters in the giant star-forming Cas OB6 association. Several interesting aspects relating to star formation processes in giant star-forming regions attracted us to study the initial mass function (IMF), star formation mode and properties of pre-main-sequence (PMS) stars. A UBVI and H{alpha} photometric study of the young open cluster IC 1848 was conducted as part of the 'Sejong Open Cluster Survey'. We have selected 10^5^ early-type members from photometric diagrams. Their mean reddening is <E(B-V)>=0.660+/-0.054mag. Using the published photometric data with near- and mid-infrared archival data we confirmed the normal reddening law (R_V_=3.1) towards the cluster (IC 1848). A careful zero-age main-sequence fitting gives a distance modulus of V_0_-M_V_=11.7+/-0.2mag, equivalent to 2.2+/-0.2kpc. H{alpha} photometry and the list of young stellar objects identified by Koenig et al. permitted us to select a large number of PMS stars comprising 196 H{alpha} emission stars, 35 H{alpha} emission candidates, 5 Class I, 368 Class II and 24 transition disc candidates. From the Hertzsprung-Russell diagram using stellar evolution models, we estimate an age of 5Myr from several evolved stars and 3Myr from the PMS stars. The IMF was derived from stars with mass larger than 3M_{sun}_, and the slope is slightly steeper ({Gamma}=-1.6+/-0.2) than the Salpeter/Kroupa IMF. Finally, we estimated the mass accretion rate of PMS stars with an ultraviolet excess. The mean mass accretion rate is about 1.4x10^-8^M_{sun}_/yr in the mass range of 0.5-2M_{sun}_, whereas intermediate-mass stars (>=2.5M_{sun}_) exhibit a much higher accretion rate of dM/dt>10^-6^M_{sun}/yr.
