Variable stars in the field of the young open cluster Roslund 2

AbstractThe study of variable stars in open clusters via asteroseismology is a powerful tool for the study of stellar evolution and stars in general. That is because stars in clusters can be assumed to originate from the same interstellar cloud, so they share similar properties such as age and overall metallicity. We performed a search for variable stars in the field of the young open star cluster Roslund 2, with photoelectric and CCD photometry acquired at two different telescopes. Within the resulting light curves we have found 12 variable stars. Our measurements confirm three previously known variables.

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The CFHT Open Star Cluster Survey. II. Deep CCD Photometry of the Old Open Star Cluster NGC 6819

The Astronomical Journal ◽

10.1086/321141 ◽

2001 ◽

Vol 122 (1) ◽

pp. 266-282 ◽

Cited By ~ 72

Author(s):

Jasonjot Singh Kalirai ◽

Harvey B. Richer ◽

Gregory G. Fahlman ◽

Jean-Charles Cuillandre ◽

Paolo Ventura ◽

...

Keyword(s):

Star Cluster ◽

Ccd Photometry ◽

Cluster Survey ◽

Open Star ◽

Open Star Cluster

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The star cluster age function in the Galactic disc with Gaia DR2

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038532 ◽

2020 ◽

Vol 645 ◽

pp. L2

Author(s):

Friedrich Anders ◽

Tristan Cantat-Gaudin ◽

Irene Quadrino-Lodoso ◽

Mark Gieles ◽

Carme Jordi ◽

...

Keyword(s):

Open Cluster ◽

Cluster Formation ◽

Formation Rate ◽

Age Distribution ◽

Star Cluster ◽

Open Clusters ◽

Open Star Clusters ◽

Open Star ◽

Formation And Evolution ◽

Cluster Age

We perform a systematic reanalysis of the age distribution of Galactic open star clusters. Using a catalogue of homogeneously determined ages for 834 open clusters contained in a 2 kpc cylinder around the Sun and characterised with astrometric and photometric data from the Gaia satellite, we find that it is necessary to revise earlier works that relied on data from the Milky Way Star Cluster survey. After establishing age-dependent completeness limits for our sample, we find that the cluster age function in the range 6.5 < log t < 10 is compatible with Schechter-type or broken power-law functions. Our best-fit values indicate an earlier drop of the age function (by a factor of 2−3) with respect to the results obtained in the last five years, and are instead more compatible with results obtained in the early 2000s along with radio observations of inner-disc clusters. Furthermore, we find a typical destruction timescale of ∼1.5 Gyr for a 104 M⊙ cluster and a present-day cluster formation rate of 0.55−0.15+0.19 Myr−1 kpc−2, suggesting that only 16−8+11% of all stars born in the solar neighbourhood form in bound clusters. Accurate cluster-mass measurements are now needed to place more precise constraints on open-cluster formation and evolution models.

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

International Astronomical Union Colloquium ◽

10.1017/s0252921100015840 ◽

2002 ◽

Vol 185 ◽

pp. 150-151 ◽

Cited By ~ 1

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.

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Variable stars in young open star cluster NGC 7380

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv2800 ◽

2015 ◽

Vol 456 (3) ◽

pp. 2505-2517 ◽

Cited By ~ 8

Author(s):

Sneh Lata ◽

A. K. Pandey ◽

Neelam Panwar ◽

W. P. Chen ◽

M. R. Samal ◽

...

Keyword(s):

Variable Stars ◽

Star Cluster ◽

Open Star ◽

Open Star Cluster

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On the Dynamics of Open Clusters

Symposium - International Astronomical Union ◽

10.1017/s0074180900147758 ◽

1985 ◽

Vol 113 ◽

pp. 521-524 ◽

Cited By ~ 4

Author(s):

V. A. Ambartsumian

Keyword(s):

Open Cluster ◽

Boltzmann Distribution ◽

Star Cluster ◽

Open Clusters ◽

Open Star Clusters ◽

Open Star ◽

Russian Edition ◽

Probable Distribution ◽

Exchange Kinetic ◽

Most Probable Distribution

It has already been pointed out in the literature that due to several causes, open star clusters dissipate with time. For instance, Rosseland showed that when external stars move through a cluster, they cause a perturbation of the motion of the stars in the cluster and could transfer enough momentum to individual stars to cause their escape from the cluster's gravitational field. In this way the cluster will lose stars gradually, i.e., it will dissipate. According to Rosseland the time needed for the star cluster to dissipate following the outlined mechanism is 1010 years. However, as pointed out by the author of this article in the supplement to the Russian edition of Rosseland's book, there is another factor that makes the life of the open cluster even shorter: the stars in the cluster have close encounters with each other, as a result of which they exchange kinetic energy and gradually tend towards the most probable distribution, i.e., a Maxwell-Boltzmann distribution. And this, as we shall see shortly, also causes the dissipation of the cluster.

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Time-Series CCD Photometry of Northern Open Clusters Using the BOAO 1.8-m Telescope: III. NGC 2301

International Astronomical Union Colloquium ◽

10.1017/s0252921100058413 ◽

2000 ◽

Vol 176 ◽

pp. 457-458

Author(s):

S.-L. Kim ◽

B.-G. Park ◽

M.-Y. Chun ◽

H. Sung ◽

Y.-B. Jeon ◽

...

Keyword(s):

Time Series ◽

Open Cluster ◽

Variable Stars ◽

Open Clusters ◽

Astronomy Observatory ◽

Ccd Photometry ◽

Preliminary Results ◽

Optical Astronomy

AbstractA time-series CCD photometric survey of variable stars in open clusters has been in progress using 1.8-m telescope at the Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We present preliminary results of time series photometry for the intermediate-age open cluster NGC 2301.

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Search for the sub-stellar lithium depletion boundary in the open star cluster Coma Berenices

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037907 ◽

2020 ◽

Vol 640 ◽

pp. A9

Author(s):

E. L. Martín ◽

N. Lodieu ◽

V. J. S. Béjar

Keyword(s):

Stellar Population ◽

Open Cluster ◽

Brown Dwarfs ◽

Star Cluster ◽

Brown Dwarf ◽

Cluster Membership ◽

Open Star ◽

Sky Survey ◽

Lithium Depletion ◽

Open Star Cluster

Aims. We mainly aim to search for the lithium depletion boundary (LDB) among the sub-stellar population of the open star cluster Coma Berenices. Methods. Since the number of brown dwarf candidates in Coma Ber available in the literature is scarce, we carried out a search for additional candidates photometrically using colour–magnitude diagrams combining optical and infrared photometry from the latest public releases of the following large-scale surveys: the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIRT/UKIDSS), the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), the Sloan Digital Sky Survey (SDSS), and AllWISE. We checked astrometric consistency with cluster membership using Gaia DR2. A search for Li in three new and five previously known brown dwarf candidate cluster members was performed via spectroscopic observations using the OSIRIS instrument at the 10.4 m Gran Telescopio de Canarias (GTC). Results. A couple dozen new photometric candidate brown dwarfs located inside the tidal radius of Coma Ber are reported, but none of these are significantly fainter and cooler than previously known members. No LiI resonance doublet at 6707.8 Å was detected in any of eight Coma Ber targets in the magnitude range J = 15–19 and G = 20–23 observed with the GTC. Spectral types and radial velocities were derived from the GTC spectra. These values confirm the cluster membership of four L2–L2.5 dwarfs, two of which are new in the literature. Conclusions. The large Li depletion factors found among the four bona fide sub-stellar members in Coma Ber implies that the LDB must be located at spectral type later than L2.5 in this cluster. Using the latest evolutionary models for brown dwarfs, a lower limit of 550 Myr on the cluster age is set. This constraint has been combined with other dating methods to obtain an updated age estimate of 780 ± 230 Myr for the Coma Ber open cluster. Identification of significantly cooler sub-stellar cluster members in Coma Ber awaits the advent of the Euclid wide survey, which should reach a depth of about J = 23; this superb sensitivity will make it possible to determine the precise location of the sub-stellar LDB in this cluster and to carry out a complete census of its sub-stellar population.

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Defining the Binary Star Population in the Young Open Cluster M35 (NGC 2168)

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308015391 ◽

2007 ◽

Vol 3 (S246) ◽

pp. 105-106

Author(s):

Ella K. Braden ◽

Robert D. Mathieu ◽

Sören Meibom

Keyword(s):

Binary Systems ◽

Initial Conditions ◽

Binary Star ◽

Open Cluster ◽

Open Clusters ◽

Spatial Period ◽

Large Sample Size ◽

Long Baseline ◽

Dynamical Simulations ◽

Young Open Cluster

AbstractWe present current results from the ongoing WIYN Open Cluster Study radial-velocity survey for 1410 stars in the young (150 Myr) open cluster M35 (NGC 2168) and establish a benchmark for initial conditions in young open clusters. We find for periods ≲ 1000 days a minimum binary frequency of 0.36 – 0.51. We also analyze the spatial, period and eccentricity distributions of the binary systems and find that the period and eccentricity distributions are well approximated by scaled field distributions from Duquennoy & Mayor (1991). With our large sample size and long baseline, we have a unique understanding of the binary population in this young cluster, making it ideal for defining initial conditions for dynamical simulations.

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