scholarly journals Investigation of contact binaries in the field of NGC 6811

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Xu-Zhi Li ◽  
Liang Liu ◽  
Xu-Dong Zhang
Keyword(s):  
Binary Systems ◽  
Open Cluster ◽  
Interstellar Extinction ◽  
Cluster Center ◽  
Strong Interactions ◽  
Cluster Distance ◽  
Metal Abundance ◽  
Contact Binaries ◽  
Contact Binary ◽  
Distance Data

Abstract Contact binary systems are very important for studying physical processes such as strong interactions between stars, mass transfer, and stellar merger. Further, the members of an open cluster have the same age, metal abundance, and interstellar extinction conditions. Therefore, we can conduct a comparative study on the different binary systems of the same open cluster. NGC 6811 is an observed intermediate-aged, slightly reddened open cluster in the Kepler field of view; we conducted a corresponding study on the contact binary systems in this cluster. We analyzed six suspected targets and found a total of five EW-type binary systems within a field of 40′ radius of the NGC 6811 cluster center. These targets were analyzed base on the Kepler data, and the corresponding system parameters were obtained by using the latest version of the Wilson–Devinney code. Further, we also used Gaia DR2 data and the cluster distance data to estimate the absolute parameters of these targets to determine whether they are members of the cluster. Finally, we determined that two targets (KIC 9470175 and KIC 9533706) are most likely cluster members; KIC 9957411 and KIC 9776718 are definitely not members of the cluster, just background stars.

scholarly journals Searching for eclipsing binaries in the area of RA: 02h21m36s, Dec: +57○11′32″

2020 ◽  
Vol 497 (3) ◽  
pp. 3381-3392
Author(s):  
Di-Fu Guo ◽  
Kai Li ◽  
Xing Gao ◽  
Dong-Yang Gao ◽  
Zhi-Jian Xu ◽  
...  
Keyword(s):  
Binary Systems ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Mass Ratio ◽  
Contact Binaries ◽  
Contact Binary ◽  
Low Mass ◽  
Low Mass Ratio ◽  
Period Decrease ◽  
Cross Matching

ABSTRACT By analysing the data observed by the Comet Search Programme telescope at Xingming Observatory from 2018 October 11 to 2018 December 19, 24 eclipsing binaries were identified. By cross-matching with the VSX (AAVSO) website, we found that four binaries are newly discovered. By analysing the Transiting Exoplanet Survey Satellite (TESS) data, the light curves of 17 binaries were obtained. First photometric solutions of 23 binaries were obtained by simultaneously analysing all the light curves, except for NSVS 1908107 (first analysed by Pan et al.). Based on the photometric solutions, nine binaries belong to detached binary systems, ten binaries belong to semidetached binary systems, and five binaries belong to contact binary systems. Two W-subtype low-mass ratio contact binaries (the less massive components are hotter), with total eclipsing light curves, were identified: Mis V1395 is a deep contact binary (q = 0.150, $f=80{{\ \rm per\ cent}}$), while NSVS 1917038 is a low-mass ratio binary with an unexpectedly marginal contact degree (q = 1/6.839 = 0.146, $f=4{{\ \rm per\ cent}}$). The total eclipsing detached binary GSC 03698-00022 has an extremely low mass ratio of q = 0.085. The Algol-type binary NSVS 1908107 is also found to have an extremely low mass ratio of q = 0.081. The Algol-type binary DK Per exhibits a continuous period decrease at a rate of dP/dt = −1.26 × 10−7 d yr−1, which may result from the orbital angular momentum loss. Based on the light curves obtained from the TESS data, a pulsating binary candidate (NSVS 1913053) was found.

scholarly journals IC 361, a distant intermediate-age cluster in Camelopardalis

2009 ◽  
Vol 5 (S266) ◽  
pp. 557-560
Author(s):  
Justas Zdanavičius ◽  
Richard P. Boyle ◽  
Frederick J. Vrba ◽  
Kazimieras Zdanavičius ◽  
Stanislava Bartašiūtė
Keyword(s):  
Open Cluster ◽  
Interstellar Extinction ◽  
Distance Modulus ◽  
Ccd Photometry ◽  
True Distance ◽  
Individual Stars ◽  
Cluster Distance ◽  
Spiral Arm

AbstractWe have undertaken CCD photometry in the eight-color Vilnius + I system for the open cluster IC 361 (l = 147.5°, b = 5.7°) located in the constellation of Camelopardalis. Based on multicolor data, estimates of distance moduli, foreground reddening and metallicity have been obtained for individual stars measured in the field of the cluster. This allowed us to eliminate most of the field stars and to identify the probable cluster members, from which we derived the true distance modulus (m − M)0 = 12.7 mag and metallicity [Fe/H] = −0.3 dex. The interstellar extinction is found to be nonuniform across the field, with values of AV ranging from 1.9 to 2.6 mag. A comparison of the color–magnitude diagrams with Padova isochrones yields (m − M)0 = 12.6 mag, or a cluster distance of 3.3 kpc, and an age of 1.0 Gyr. Therefore, IC 361 appears to be a mildly metal-deficient cluster of intermediate age, located as far as, or just beyond, the Perseus spiral arm.

scholarly journals Wide Field Photometric Study of Galactic Cluster NGC 6067

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Alok K. Durgapal ◽  
Geeta Rangwal ◽  
R. K. S. Yadav
Keyword(s):  
Heliocentric Distance ◽  
Open Cluster ◽  
Interstellar Extinction ◽  
Cluster Center ◽  
Wide Field ◽  
Photometric Study ◽  
Galactic Cluster ◽  
Archive Data

We conduct wide field BV photometry of open cluster NGC 6067 using the archive data taken from [email protected] catalogue. The astrophysical parameters of the cluster such as age, cluster center and heliocentric distance using colour magnitude diagrams are calculated. We also calculated the value of interstellar extinction in the direction of this cluster.

scholarly journals CoBiToM project – I. Contact binaries towards merging

2021 ◽  
Vol 502 (2) ◽  
pp. 2879-2892
Author(s):  
K D Gazeas ◽  
G A Loukaidou ◽  
P G Niarchos ◽  
S Palafouta ◽  
D Athanasopoulos ◽  
...  
Keyword(s):  
Stellar Evolution ◽  
Binary Systems ◽  
Temporal Variations ◽  
Eclipsing Binaries ◽  
Stellar Systems ◽  
Rotating Stars ◽  
Multiple Star ◽  
Contact Binaries ◽  
Contact Binary ◽  
Stellar Mergers

ABSTRACT Binary and multiple stellar systems are numerous in our solar neighbourhood with 80 per cent of the solar-type stars being members of systems with high order multiplicity. The Contact Binaries Towards Merging (CoBiToM) Project is a programme that focuses on contact binaries and multiple stellar systems, as a key for understanding stellar nature. The goal is to investigate stellar coalescence and merging processes, as the final state of stellar evolution of low-mass contact binary systems. Obtaining observational data of approximately 100 eclipsing binaries and multiple systems and more than 400 archival systems, the programme aspires to give insights for their physical and orbital parameters and their temporal variations, e.g. the orbital period modulation, spot activity etc. Gravitational phenomena in multiple-star environments will be linked with stellar evolution. A comprehensive analysis will be conducted, in order to investigate the possibility of contact binaries to host planets, as well as the link between inflated hot Jupiters and stellar mergers. The innovation of CoBiToM Project is based on a multimethod approach and a detailed investigation, that will shed light for the first time on the origin of stellar mergers and rapidly rotating stars. In this work, we describe the scientific rationale, the observing facilities to be used and the methods that will be followed to achieve the goals of CoBiToM Project and we present the first results as an example of the current research on evolution of contact binary systems.

scholarly journals Young open cluster IC 4996 and its vicinity: multicolor photometry and Gaia DR2 astrometry

2019 ◽  
Vol 623 ◽  
pp. A22 ◽  
Author(s):  
V. Straižys ◽  
R. P. Boyle ◽  
K. Milašius ◽  
K. Černis ◽  
M. Macijauskas ◽  
...  
Keyword(s):  
Open Cluster ◽  
Interstellar Extinction ◽  
Mean Value ◽  
Photometric System ◽  
B Stars ◽  
Dust Clouds ◽  
Wide Range ◽  
Cluster Distance ◽  
Young Open Cluster ◽  
Similar Distance

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 AV 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 ± 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 AV 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 ≥ 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 ± 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.

scholarly journals Physical parameters of close binary systems: VIII

2021 ◽  
Author(s):  
K Gazeas ◽  
S Zola ◽  
A Liakos ◽  
B Zakrzewski ◽  
S M Rucinski ◽  
...  
Keyword(s):  
Binary Systems ◽  
Extreme Values ◽  
Close Binary ◽  
Physical Parameters ◽  
Evolutionary Status ◽  
Mass Ratio ◽  
Orbital Parameters ◽  
Contact Binaries ◽  
Contact Binary ◽  
Orbital Periods

Abstract This paper presents the results of a combined spectroscopic and photometric study of 20 contact binary systems: HV Aqr, OO Aql, FI Boo, TX Cnc, OT Cnc, EE Cet, RW Com, KR Com, V401 Cyg, V345 Gem, AK Her, V502 Oph, V566 Oph, V2612 Oph, V1363 Ori, V351 Peg, V357 Peg, Y Sex, V1123 Tau and W UMa, which was conducted in the frame of the W UMa Project. Together with 51 already covered by the project and an additional 67 in the existing literature, these systems bring the total number of contact binaries with known combined spectroscopic and photometric solutions to 138. It was found that mass, radius and luminosity of the components follow certain relations along the MS and new empirical power relations are extracted. We found that 30 per cent of the systems in the current sample show extreme values in their parameters, expressed in their mass ratio or fill-out factor. This study shows that, among the contact binary systems studied, some have an extremely low mass ratio (q<0.1) or an ultra-short orbital period (Porb <0.25 d), which are expected to show evidence of mass transfer progress. The evolutionary status of these components is discussed with the aid of correlation diagrams and their physical and orbital parameters compared to those in the entire sample of known contact binaries. The existence of very short orbital periods confirms the very slow nature of the merging process, which seems to explain why their components still exist as MS stars in contact configurations even after several Gyr of evolution.

scholarly journals Wide Field Photometric Study of Galactic Cluster NGC 6067

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Alok K. Durgapal ◽  
Geeta Rangwal ◽  
R. K. S. Yadav
Keyword(s):  
Heliocentric Distance ◽  
Open Cluster ◽  
Interstellar Extinction ◽  
Cluster Center ◽  
Wide Field ◽  
Photometric Study ◽  
Galactic Cluster ◽  
Archive Data

We conduct wide field BV photometry of open cluster NGC 6067 using the archive data taken from [email protected] catalogue. The astrophysical parameters of the cluster such as age, cluster center and heliocentric distance using colour magnitude diagrams are calculated. We also calculated the value of interstellar extinction in the direction of this cluster.

Distribution of physical parameters for 380 contact binaries in the Kepler field

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Xu-Zhi Li ◽  
Liang Liu ◽  
Li-Ying Zhu
Keyword(s):  
Binary Systems ◽  
Large Mass ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Mass Ratio ◽  
Eclipsing Binary ◽  
Contact Binaries ◽  
Contact Binary ◽  
Low Mass ◽  
Low Mass Ratio

Abstract We present the physical parameters (p, T, q, i, f) of 380 Kepler contact binary systems (hereafter called CBs). A statistical study on the CBs is carried out based on a Kepler photometric database. Our samples were selected from the Kepler Eclipsing Binary Catalogue of EW-type eclipsing binaries with periods around 0.2–1 d and amplitudes greater than $5\%$. The physical parameters were obtained by fitting the Kepler light curves with the Wilson–Devinney eclipsing binary modeling program. Our sample of CBs contains 160 A-type and 220 W-type CBs. The fill-out factor distribution indicated that CBs generally have shallow fill-out; the proportion of CBs with fill-out factors less than $30\%$ is around $70\%$, which may be related to the formation and evolution of the CBs. The period–temperature relationship of CBs is consistent with previous studies, which is the well-known period–color relationship. The distribution between mass ratio and fill-out factor can provide some information for studying the deep, low-mass ratio contact binaries and CBs which have a large mass ratio. The mass–radius diagram shows that there is a similar linear relationship between the primary and secondary stars while the primary stars are located almost on the ZAMS line; this could be related to the internal nuclear reaction within the primary and secondary stars.

scholarly journals Long term period behaviour of contact binaries

1986 ◽  
Vol 118 ◽  
pp. 295-295 ◽  
Author(s):  
H. D. Kennedy
Keyword(s):  
Mass Flow ◽  
Binary Systems ◽  
Equipotential Surface ◽  
Active Systems ◽  
Contact Configuration ◽  
Contact Binaries ◽  
Contact Binary ◽  
Zero Velocity Surfaces

Determination of the rate of mass flow in contact binary systems is one of the most important motives for their observation. Many of these binaries are in over-contact configuration with a common equipotential surface located somewhwere between the inner and outer Lagrangian zero-velocity surfaces. Most are active systems displaying frequent lightcurve and period changes resulting in residuals behaviour depictable by intersecting linear segments.

scholarly journals Refining the true parameters of the open cluster NGC 4852

2009 ◽  
Vol 5 (S266) ◽  
pp. 539-539
Author(s):  
Gladys Solivella ◽  
Edgard Giorg ◽  
Rubén Vázquez ◽  
Giovanni Carraro
Keyword(s):  
Emission Line ◽  
Open Cluster ◽  
Open Clusters ◽  
Occurrence Rate ◽  
Hot Stars ◽  
Cluster Area ◽  
Young Object ◽  
Cluster Distance ◽  
Be Star ◽  
Compact Cluster

AbstractNGC 4852 is a moderately compact cluster centered at α2000 = 13 : 00 : 09; δ = −59 : 36 : 48, located near the center of an Hα superring. This cluster forms part of an extended region including young stellar aggregates inside a circle with a radius of 3 degrees, where many show an abundance of emission line stars. In the field of this cluster, two stars of known type exist: Wray 15–1039 (emission-line object) and CD −58:4845 (emission-line star). We do not yet know whether the Be phase is transient or whether it is just what randomly happens in some hot stars. It appears that Be star may be found even in clusters as old as 70 Myr with a high occurrence rate in clusters of 25–27 Myr old. A recent photometric survey in NGC 4852 down to V = 22 – 23 mag established that NGC 4852 is about 200 – 250 Myr old, located at 1.1 kpc from the Sun and with a mean E(B − V) = 0.45 mag. Since the presence of potential Be-type stars in the cluster area suggests it may be a very young object instead of moderately old, we decided to carry out spectroscopy for 33 selected stars and CCD UBVI photometry for the bright objects in the cluster area. This way, we attempt to clarify their evolutionary state and include them in the framework of emission-line stars and open clusters. From our analysis, we agree with the cluster distance and reddening determined by earlier studies, but we derive that the age of NGC 4852 is younger than 40 Myr.

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