Photoelectric photometry of the open cluster Tr-1

1977 ◽  
Vol 48 (1) ◽  
pp. 225-230 ◽  
Author(s):  
U. C. Joshi ◽  
Ram Sagar
Keyword(s):  
Open Cluster ◽  
Photoelectric Photometry

scholarly journals The Open Cluster M67 as a Fundamental Standard of Reference for Stellar Properties

1985 ◽  
Vol 111 ◽  
pp. 361-364
Author(s):  
Kenneth Janes
Keyword(s):  
Open Cluster ◽  
Accurate Determination ◽  
Distance Modulus ◽  
The Sun ◽  
Distance Measurements ◽  
Photoelectric Photometry ◽  
Sources Of Error ◽  
Motion Studies ◽  
Stellar Properties

With the possible exception of the Hyades, M67 is the best-studied star cluster. Accurate photoelectric photometry exists well down onto the main sequence and proper motion studies have isolated cluster stars from the field. From photometry and spectroscopy, its composition is determined to be almost exactly the same as the Sun, with an age about one-half billion years less. This similarity to the Sun permits an accurate determination of distance to M67 independently of other distance measurements. Using the Sun as a reference, the distance modulus of M67 is found to be 9.48 mag. An extensive analysis of possible sources of error leads to an uncertainty (standard error) of ± 0.15 mag., with the chief sources of error being the color index of the Sun, the composition of the cluster, and its age. The M67 distance uncertainty compares favorably with Hanson's (1975) Hyades modulus of 3.29 ± 0.08.

Photoelectric photometry of the open cluster NGC 1778

Pramana ◽  
1975 ◽  
Vol 4 (4) ◽  
pp. 160-163 ◽  
Author(s):  
U C Joshi ◽  
R Sagar ◽  
P Pandey
Keyword(s):  
Open Cluster ◽  
Photoelectric Photometry

scholarly journals STUDY OF THE OPEN CLUSTER NGC 1528 THROUGH uvby − β PHOTOELECTRIC PHOTOMETRY

2019 ◽  
Vol 55 (2) ◽  
pp. 203-209
Author(s):  
J. H. Peña ◽  
J. Calderón ◽  
D. S. Piña
Keyword(s):  
Open Cluster ◽  
Photoelectric Photometry ◽  
Cluster A

uvby − β photoelectric photometry of sixty-five stars in the direction of the open cluster NGC 1528 is presented. From the uvby − β photometry of the cluster we classified the spectral types of the stars which allowed us to determine the reddening (E(b-y) of 0.196 ± 0.054) and hence, their distance, in parsecs, of (954 ± 154). We determined membership of the stars to the cluster and the age (Log age equal 8.04) of the cluster. A metallicity [Fe/H] of −0.31 ± 0.08 was calculated.

Interstellar Extinction in the Direction of The Barnard 1 Dark Cloud in Perseus

2003 ◽  
Vol 12 (3) ◽  
Author(s):  
K. Černis ◽  
V. Straižys
Keyword(s):  
Open Cluster ◽  
Interstellar Extinction ◽  
Photometric System ◽  
Dark Cloud ◽  
Photoelectric Photometry ◽  
Reflection Nebula ◽  
Absolute Magnitudes ◽  
Cloud Complex

AbstractSpectral and luminosity classes, absolute magnitudes, color excesses, interstellar extinctions and distances are determined for 98 stars down to 18 mag in the Barnard 1 dark cloud belonging to the Per OB2 association. The classification of stars is based on their photoelectric photometry in the Vilnius seven-color photometric system. The extinction vs. distance diagram exhibits the presence of two dust layers at 150 and 230 pc distances. The distance of the first cloud, which gives an extinction Ay of 0.3 mag, coincides with the distance of the Taurus dark cloud complex. The second cloud with much larger extinction is about at the same distance as the clouds in the direction of the nearby objects: reflection nebula NGC 1333 and open cluster IG 348.

Multicolour photoelectric photometry of the open cluster NGC 752

1993 ◽  
Vol 199 (1) ◽  
pp. 77-87 ◽  
Author(s):  
U. Dz�rv�tis ◽  
O. Paupers
Keyword(s):  
Open Cluster ◽  
Photoelectric Photometry

scholarly journals SOME REMARKS ON THE OPEN CLUSTER UPGREN 1 USING uvby − β PHOTOELECTRIC PHOTOMETRY

2019 ◽  
Vol 55 (2) ◽  
pp. 221-229 ◽  
Author(s):  
J. H. Peña ◽  
A. Rentería ◽  
H. Huepa ◽  
A. Pani
Keyword(s):  
Open Cluster ◽  
Radial Velocities ◽  
Photoelectric Photometry ◽  
The Past ◽  
Empirical Relations

The open cluster Upgren 1 presents peculiar features that in the past led to divergent opinions about its existence. In previous studies of other clusters, uvby − β photoelectric photometry has shown results in agreement with other techniques; therefore, the photometry obtained in the present work has been combined with data from previous studies to examine the brightest stars in the direction of the cluster. Analyzing the unreddened indexes, we found that all the stars are of late spectral types. Applying the empirical relations of Nissen (1987) to determine the reddening and, consequently, the unreddened indexes, we found that all but three are located at a distance of 123 ± 17 pc. The assigned membership in this study is in concordance with that of Upgren, Philip and Beaver (1982) obtained through radial velocities.

Seven-color photoelectric photometry of stars in the Alpha Persei open cluster

1994 ◽  
Vol 3 (4) ◽  
Author(s):  
U. Dzērvītis ◽  
O. Paupers ◽  
V. Vansevičius
Keyword(s):  
Open Cluster ◽  
Photoelectric Photometry ◽  
Alpha Persei

Radial Velocities, Binarity, and Kinematic Membership in the Open Cluster NGC 2516

2000 ◽  
Vol 119 (5) ◽  
pp. 2296-2302 ◽  
Author(s):  
Jorge Federico González ◽  
Emilio Lapasset
Keyword(s):  
Open Cluster ◽  
Radial Velocities

scholarly journals Formation rate of LB-1-like systems through dynamical interactions

2020 ◽  
Vol 72 (3) ◽  
Author(s):  
Ataru Tanikawa ◽  
Tomoya Kinugawa ◽  
Jun Kumamoto ◽  
Michiko S Fujii
Keyword(s):  
Open Cluster ◽  
Formation Rate ◽  
Open Clusters ◽  
Type Star ◽  
Dynamical Mechanism ◽  
Milky Way Galaxy ◽  
Triple Systems ◽  
Stellar Collisions ◽  
Solar Metallicity ◽  
Helium Star

Abstract We estimate formation rates of LB-1-like systems through dynamical interactions in the framework of the theory of stellar evolution before the discovery of the LB-1 system. The LB-1 system contains a ∼70 ${M_{\odot}}$ black hole (BH), a so-called pair instability (PI) gap BH, and a B-type star with solar metallicity, and has nearly zero eccentricity. The most efficient formation mechanism is as follows. In an open cluster, a naked helium star (with ∼20 ${M_{\odot}}$) collides with a heavy main sequence star (with ∼50 ${M_{\odot}}$) which has a B-type companion. The collision results in a binary consisting of the collision product and the B-type star with a high eccentricity. The binary can be circularized through the dynamical tide with radiative damping of the collision product envelope. Finally, the collision product collapses to a PI-gap BH, avoiding pulsational pair instability and pair instability supernovae because its He core is as massive as the pre-colliding naked He star. We find that the number of LB-1-like systems in the Milky Way galaxy is ∼0.01(ρoc/104 ${M_{\odot}}$ pc−3), where ρoc is the initial mass densities of open clusters. If we take into account LB-1-like systems with O-type companion stars, the number increases to ∼0.03(ρoc/104 ${M_{\odot}}$ pc−3). This mechanism can form LB-1-like systems at least ten times more efficiently than the other mechanisms: captures of B-type stars by PI-gap BHs, stellar collisions between other types of stars, and stellar mergers in hierarchical triple systems. We conclude that no dynamical mechanism can explain the presence of the LB-1 system.

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