Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userYoung open cluster IC 4996 and its vicinity: multicolor photometry and Gaia DR2 astrometry
401
0
0.0
(
0
)
Added by
Algirdas Kazlauskas
Publication date
2019
fields
Physics
and research's language is
English
Authors
V. Straiv{z}ys
Ask ChatGPT about the research
No Arabic abstract
The open cluster IC 4996 in Cygnus and its vicinity are investigated by applying a two-dimensional photometric classification of stars measured in the Vilnius seven-color photometric system. Cluster members are identified by applying distances based on the Gaia DR2 parallaxes and the point vector diagram of the Gaia DR2 proper motions. For some B-type stars, spectroscopic MK types are also obtained from the Asiago spectra and collected from the literature. New parameters of the cluster are derived. The interstellar extinction $A_V$ covers a wide range of values, from 1.3 to 2.4 mag; the mean value in the central part of the cluster is 1.8 mag. The cluster distance is 1915 $pm$ 110 pc, and its age is within 8-10 Myr. The cluster exhibits a long sequence from early-B to G stars, where stars cooler than B8 are in the pre-main-sequence stage. The plot of extinction versus distance shows a steep rise of $A_V$ up to 1.6 mag at 700-800 pc, which is probably related to dust clouds at the edge of the Great Cygnus Rift. The next increase in extinction by an additional 0.8 mag at $d$ $geq$ 1.7 kpc is probably related to the associations Cyg OB1 and Cyg OB3. The cluster IC 4996 does not belong to the Cyg OB1 association, which is located closer to the Sun, at 1682 $pm$ 116 pc. It seems likely that the cluster and the surrounding O-B stars have a common origin with the nearby association Cyg OB3 since Gaia data show that these stellar groups are located at a similar distance.
rate research
Read More
We present a detailed photometric and kinematical analysis of poorly studied open cluster IC 1434 using CCD VRI, APASS, and Gaia DR2 database for the first time. BY determining the membership probability of stars, we identified the 238 most probable members with a probability higher than 60% by using proper motion and parallax data as taken from the Gaia DR2 catalog. The mean proper motion of the cluster is obtained as emu_x= - 3.89 +/- 0.19 and emu_y= - 3.34 +/- 0.19 mas/yr in both the directions of right ascension and declination. The radial distribution of member stars provides cluster extent as 7.6 arcmin. We have estimated the interstellar reddening (E(B-V)) as 0.34 mag using the transformation equations from literature. We obtained the values of cluster age and distance are 631 +/- 73 Myr and 3.2 +/- 0.1 Kpc.
In this paper, we present astrophysical parameters of the open cluster King 13 based on the VI CCD and 2MASS JHKs photometric data. This is a poorly studied cluster, for which new results have been found in the present work. To identify probable members, we use proper motion data from Gaia DR2 catalogue. The mean proper motion of the cluster is determined as -2.8 pm 0.2 and -0.88 pm 0.14 mas yr{-1} and cluster extent is derived as 3.2. Using color-magnitude diagrams, we estimate the age and distance of the cluster as 510 pm 60 Myr and 3.84 pm 0.15 kpc respectively. Interstellar reddening E(B-V) in the direction of the cluster is determined as 0.80 pm 0.2 mag using color-color diagram. Mass function slope of the cluster is found to be comparable with the Salpeter value. The total mass of this cluster is derived as 270 M_{odot}. The present analysis shows that King 13 is a dynamically relaxed cluster.
The kinematical parameters, spatial shape and structure of the open cluster IC 2391 and the associated stellar stream are studied here using Gaia-DR2 (GDR2) astrometry data. The apex positions are determined for the open cluster IC 2391 (data taken from Cantat-Gaudin et al.) and for the kinematical streams stars mentioned in Montes et al. using both convergent point and AD-diagram methods. The values of apex coordinates identified. The results are in good agreement with the previously calculated values. The positions of the stars in the disk and the spatial dispersion velocities are determined. The paths of cluster and associated stream are traced in the disk by orbit calculation back in time to their places of formation. A possible genetic relationship between the cluster and the stream has been detected. The approximation of the spatial and kinematical shape of the stream and the cluster is made. According to this study, even though currently the cluster and the stream seem to have spatial difference in their locations but they appear to have formed in the same region of the Galactic disk.
We present reddening, photometric metallicity, age and distance estimates for the Frolov 1 and NGC 7510 open clusters based on CCD UBV photometric and Gaia data. Photometric observations were collected using the 1-m telescope of the TUB.ITAK National Observatory. Gaia DR2 proper motion data in the direction of two groupings were used to identify cluster membership. We determined mean proper motion values ($ mu_{alpha}cosdelta, mu_{delta}$) = ($-3.02pm 0.10$, $-1.75 pm 0.08$) and ($-3.66 pm 0.07$, $-2.17 pm 0.06$) mas yr$^{-1}$ for Frolov 1 and NGC 7510, respectively. We used two-colour diagrams to obtain $E(B-V)$ colour excesses for Frolov 1 and NGC 7510 as $0.65pm0.06$ and $1.05pm0.05$ mag, respectively. We derived the photometric metallicity of Frolov 1 as [Fe/H] = 0.03$pm$0.03 dex and adopted a solar metallicity for NGC 7510. Based on these reddening and metallicities we determined the distance moduli and ages of the clusters via fitting PARSEC isochrones to the cluster colour-magnitude diagrams. Isochrone fitting distances for Frolov 1 and NGC 7510 are $2864 pm 254$ and $2818 pm 247$ pc, respectively, which correspond to the ages $35pm 10$ Myr and $18pm 6$ Myr. We also calculated mean Gaia distances and compared them with those given in the literature and in this study, concluding that our results are in good agreement with previous work. Finally, we calculated the mass function slopes as being $X=-1.21pm0.18$ for Frolov 1 and $X=-1.42pm0.27$ for NGC 7510.
Very precise observational data are needed for studying the stellar cluster parameters (distance, reddening, age, metallicity) and cluster internal kinematics. In turn, these give us an insight into the properties of our Galaxy, for example, by giving us the ability to trace Galactic spiral structure, star formation rates and metallicity gradients. We investigated the available Gaia DR2 catalogue of 1229 open clusters and studied cluster distances, sizes and membership distributions in the 3D space. An appropriate analysis of the parallaxto-distance transformation problem is presented in the context of getting distances toward open clusters and estimating their sizes. Based on our investigation of the Gaia DR2 data we argue that, within 2 kpc, the inverse-parallax method gives comparable results (distances and sizes) as the Bayesian approach based on the exponentially decreasing volume density prior. Both of these methods show very similar dependence of the line-of-sight elongation of clusters (needle-like shapes resulting from the parallax uncertainties) on the distance. We also looked at a measure of elongations of the studied clusters and find the maximum distance of 665 pc at which a spherical fit still contains about half of the stellar population of a cluster. It follows from these results that the 3D structure of an open cluster cannot be properly studied beyond about 500 pc when using any of mentioned standard transformations of parallaxes to distances.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
