scholarly journals Photometric, kinematic, and variability study in the young open cluster NGC 1960

2020 ◽  
Vol 492 (3) ◽  
pp. 3602-3621 ◽  
Author(s):  
Y C Joshi ◽  
J Maurya ◽  
A A John ◽  
A Panchal ◽  
S Joshi ◽  
...  
Keyword(s):  
Open Cluster ◽  
Mass Range ◽  
Mass Function ◽  
Variable Stars ◽  
B Stars ◽  
V Band ◽  
Short Period ◽  
Young Open Cluster ◽  
Mass Segregation ◽  
Variability Study

ABSTRACT We present a comprehensive photometric analysis of a young open cluster NGC 1960 (= M36) along with the long-term variability study of this cluster. Based on the kinematic data of Gaia DR2, the membership probabilities of 3871 stars are ascertained in the cluster field among which 262 stars are found to be cluster members. Considering the kinematic and trigonometric measurements of the cluster members, we estimate a mean cluster parallax of 0.86 ± 0.05 mas and mean proper motions of μRA = −0.143 ± 0.008 mas yr−1 and μDec. = −3.395 ± 0.008 mas yr−1. We obtain basic parameters of the cluster such as E(B − V) = 0.24 ± 0.02 mag, log(Age/yr) = 7.44 ± 0.02, and d = 1.17 ± 0.06 kpc. The mass function slope in the cluster for the stars in the mass range of 0.72–7.32 M⊙ is found to be γ = −1.26 ± 0.19. We find that mass segregation is still taking place in the cluster which is yet to be dynamically relaxed. This work also presents first high-precision variability survey in the central 13 arcmin × 13 arcmin region of the cluster. The V-band photometric data accumulated on 43 nights over a period of more than 3 yr reveals 76 variable stars among which 72 are periodic variables. Among them, 59 are short period (P < 1 d) and 13 are long period (P > 1 d). The variable stars have V magnitudes ranging between 9.1 to 19.4 mag and periods between 41 min and 10.74 d. On the basis of their locations in the H–R diagram, periods, and characteristic light curves, 20 periodic variables belong to the cluster are classified as 2 δ-Scuti, 3 γ-Dor, 2 slowly pulsating B stars, 5 rotational variables, 2 non-pulsating B stars, and 6 as miscellaneous variables.

scholarly journals The disintegrating old open cluster Czernik 3

2020 ◽  
Vol 498 (2) ◽  
pp. 2309-2322
Author(s):  
Saurabh Sharma ◽  
Arpan Ghosh ◽  
D K Ojha ◽  
R Pandey ◽  
T Sinha ◽  
...  
Keyword(s):  
Proper Motion ◽  
Near Infrared ◽  
Open Cluster ◽  
Mass Range ◽  
Mass Function ◽  
Optical Telescope ◽  
Motion Data ◽  
Tidal Interactions ◽  
Mass Segregation ◽  
Gaia Dr2

ABSTRACT We have performed a detailed analysis of the Czernik 3 (Cz3) open cluster by using deep near-infrared photometry taken with TIRCAM2 on the 3.6 m Devasthal optical telescope along with the recently available high-quality proper motion data from the Gaia DR2 and deep photometric data from Pan-STARRS1. The cluster has a highly elongated morphology with fractal distribution of stars. The core and cluster radii of the cluster are estimated as 0.5 and 1.2 pc, respectively. We have identified 45 stars as cluster members using the Gaia proper motion data. The distance and age of the cluster are found to be 3.5 ± 0.9 kpc and $0.9^{+0.3}_{-0.1}$ Gyr, respectively. The slope of the mass function `Γ′ in the cluster region, in the mass range ∼0.95 <M/M⊙ < 2.2, is found to be −1.01 ± 0.43. The cluster shows the signatures of mass segregation and is dynamically relaxed (dynamical age = 10 Myr). This along with its small size, big tidal radius, low density/large separation of stars, and elongated and distorted morphology indicates that the Cz3 is a loosely bound disintegrating cluster under the influence of external tidal interactions.

scholarly journals CCD Photometry of Variable Stars in the Galactic Open Cluster NGC 7419

2002 ◽  
Vol 185 ◽  
pp. 150-151 ◽  
Author(s):  
Z. Kołaczkowski ◽  
A. Pigulski ◽  
G. Kopacki
Keyword(s):  
Time Scales ◽  
Open Cluster ◽  
Variable Stars ◽  
Be Stars ◽  
Ccd Photometry ◽  
Period Variability ◽  
Short Period ◽  
Young Open Cluster ◽  
Almost All ◽  
Different Time Scales

AbstractWe present results of a CCD variability search in the field of the young open cluster NGC 7419. This cluster contains a large number of Be stars and almost all of them turned out to be variable. They show mostly irregular variations on different time-scales with ranges up to 0.4 mag in the IC band. The most interesting result is the discovery of short-period variability in some of the Be stars.

scholarly journals Variable stars in the field of intermediate-age open cluster NGC 559

2020 ◽  
Vol 499 (1) ◽  
pp. 618-630
Author(s):  
Y C Joshi ◽  
Ancy A John ◽  
J Maurya ◽  
A Panchal ◽  
Brijesh Kumar ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Open Cluster ◽  
Variable Stars ◽  
Photometric Variability ◽  
Eclipsing Binary ◽  
V Band ◽  
Target Field ◽  
Periodicity Analysis ◽  
Short Period

ABSTRACT This work presents the first long-term photometric variability survey of the intermediate-age open cluster NGC 559. Time series V-band photometric observations on 40 nights taken over more than 3 yr with three different telescopes are analysed to search for variable stars in the cluster. We investigate the data for the periodicity analysis and reveal 70 variable stars including 67 periodic variables in the target field, all of them are newly discovered. The membership analysis of the periodic variables reveals that 30 of them belong to the cluster and remaining 37 are identified as field variables. Out of the 67 periodic variables, 48 are short-period (P < 1 d) variables and 19 are long-period (P > 1 d) variables. The variable stars have periodicity between 3 h to 41 d and their brightness ranges from V  = 10.9 to 19.3 mag. The periodic variables belonging to the cluster are then classified into different variability types on the basis of observational properties such as shape of the light curves, periods, amplitudes, as well as their positions in the Hertzsprung–Russell (H–R) diagram. As a result, we identify 1 Algol type eclipsing binary, 1 possible blue straggler star, 3 slowly pulsating B type stars, 5 rotational variables, 11 non-pulsating variables, 2 FKCOM variables, and remaining 7 are characterized as miscellaneous variables. We also identify three eclipsing binary stars (EBs) belonging to the field star population. The phoebe package is used to analyse the light curve of all four EBs in order to determine the parameters of the binary systems such as masses, temperatures, and radii.

scholarly journals Short-period Variable Stars in Young Open Cluster Stock 8

2019 ◽  
Vol 158 (2) ◽  
pp. 68 ◽  
Author(s):  
Sneh Lata ◽  
Anil K. Pandey ◽  
Ram Kesh Yadav ◽  
Andrea Richichi ◽  
Puji Irawati ◽  
...  
Keyword(s):  
Open Cluster ◽  
Variable Stars ◽  
Short Period ◽  
Young Open Cluster ◽  
Period Variable

scholarly journals NGC 1893: a young open cluster rich in multitype variable stars

2018 ◽  
Vol 482 (1) ◽  
pp. 658-697
Author(s):  
Hui-Fang Xue ◽  
Jian-Ning Fu ◽  
Nami Mowlavi ◽  
Sophie Saesen ◽  
Fabio Barblan ◽  
...  
Keyword(s):  
Open Cluster ◽  
Variable Stars ◽  
Young Open Cluster

scholarly journals A census of the nearby Pisces-Eridanus stellar stream

2020 ◽  
Vol 638 ◽  
pp. A9 ◽  
Author(s):  
Siegfried Röser ◽  
Elena Schilbach
Keyword(s):  
Luminosity Function ◽  
Open Cluster ◽  
Space Velocity ◽  
Mass Function ◽  
Molecular Gas ◽  
Cylindrical Shape ◽  
The Sun ◽  
Data Set ◽  
Mass Segregation ◽  
Formation Efficiency

Aims. Within a sphere of 400 pc radius around the Sun, we aim to search for members of the Pisces-Eridanus (Psc-Eri) stellar stream in the Gaia Data Release 2 data set. We compare basic astrophysical characteristics of the stream with those of the Pleiades. Methods. We used a modified convergent-point method to identify stars with 2D velocities consistent with the space velocity of the Psc-Eri stream and the Pleiades, respectively. Results. In a G magnitude range from 5.1 mag to 19.3 mag, we found 1387 members of the Psc-Eri stream at distances between 80 and 380 pc from the Sun. The stream has a nearly cylindrical shape with a length of at least 700 pc and a thickness of 100 pc. The accumulated stellar mass of the 1387 members amounts to about 770 M⊙, and the stream is gravitationally unbound. For the stream, we found an age of about 135 Myr. In many astrophysical properties, Psc-Eri is comparable to the open cluster M45 (the Pleiades): in its age, its luminosity function, its present-day mass function, as well as in its total mass. Nonetheless, the two stellar ensembles are completely different in their physical appearance. We cautiously give two possible explanations for this disagreement: (i) the star formation efficiency in their parental molecular clouds was higher for the Pleiades than for Psc-Eri, and/or (ii) the Pleiades had a higher primordial mass segregation immediately after the expulsion of the molecular gas of the parental cloud.

scholarly journals Mass Segregation in the Young SMC Cluster NGC 330

2002 ◽  
Vol 207 ◽  
pp. 687-690
Author(s):  
Marco Sirianni ◽  
Antonella Nota ◽  
Guido De Marchi ◽  
Claus Leitherer ◽  
Mark Clampin
Keyword(s):  
Luminosity Function ◽  
Radial Distance ◽  
Mass Range ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Cluster Center ◽  
Central Regions ◽  
Mass Segregation ◽  
The Imf

We present a new study of the low end of the stellar IMF of NGC 330, the richest young star cluster in the Small Magellanic Cloud (SMC). Using deep broadband images taken with the HST/WFPC2 we have derived the cluster's luminosity function and constructed the initial mass function (IMF) in the mass range 1 − 7M⊙. We have investigated the IMF as a function of the radial distance from the cluster center. We find that, after correction for background contamination, the IMF is fairly homogeneous with a slope slightly steeper than Salpeter's in the central regions of the cluster (< 40″) but becomes increasingly steeper with distance, indicating a preponderance of massive stars in the core of the cluster. NGC 330 is one of the first clusters for which evidence of mass segregation is directly found.

scholarly journals On the new late B- and early A-type periodic variable stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 43-46
Author(s):  
Nami Mowlavi ◽  
Sophie Saesen ◽  
Fabio Barblan ◽  
Laurent Eyer
Keyword(s):  
Small Amplitude ◽  
Open Cluster ◽  
Variable Stars ◽  
B Stars ◽  
Standard Models

AbstractWe summarize the properties of the new periodic, small-amplitude, variable stars recently discovered in the open cluster NGC 3766. They are located in the region of the Hertzsprung-Russell diagram between δ Sct and slowly pulsating B stars, a region where no sustained pulsation is predicted by standard models. The origin of their periodic variability is currently unknown. We also discuss how the Gaia mission, launched at the end of 2013, can contribute to our knowledge of those stars.

scholarly journals Exploring the lower mass function in the young open cluster IC 4665

2006 ◽  
Vol 448 (1) ◽  
pp. 189-202 ◽  
Author(s):  
W. J. de Wit ◽  
J. Bouvier ◽  
F. Palla ◽  
J.-C. Cuillandre ◽  
D. J. James ◽  
...  
Keyword(s):  
Open Cluster ◽  
Mass Function ◽  
Lower Mass ◽  
Young Open Cluster

scholarly journals Pre-main-sequence variable stars in young open cluster NGC 1893

2012 ◽  
Vol 427 (2) ◽  
pp. 1449-1462 ◽  
Author(s):  
Sneh Lata ◽  
A. K. Pandey ◽  
W. P. Chen ◽  
G. Maheswar ◽  
Neelam Chauhan
Keyword(s):  
Main Sequence ◽  
Open Cluster ◽  
Variable Stars ◽  
Young Open Cluster
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