scholarly journals Composite Colour-Magnitude and Colour-Colour Diagrams for Be Stars in Open Clusters

1982 ◽  
Vol 98 ◽  
pp. 23-26
Author(s):  
J.-C. Mermilliod
Keyword(s):  
Age Groups ◽  
Open Clusters ◽  
Be Stars ◽  
Photoelectric Photometry ◽  
Absolute Magnitudes ◽  
Colour Indices

By the end of 1980, the total number of Be stars discovered in the field of open clusters amounted to 180 stars distributed in 60 clusters. Among these, 110 Be stars belong to 32 clusters included in the sample I studied, which contains 75 open clusters younger than the Hyades. But only 88 stars with complete UBV photoelectric photometry have been taken into consideration here. The concept of age groups, defined elsewhere (Mermilliod 1981a), is used throughout the present analysis, as well as the new estimate of the colour excesses and distance moduli I obtained for these 32 clusters. Under the assumption of uniform reddening across the clusters, absolute magnitudes and dereddened colour indices have been calculated for the 88 Be stars.

scholarly journals Comparative Study of Young Open Clusters: Age Determination and Stellar Content

1980 ◽  
Vol 85 ◽  
pp. 245-245
Author(s):  
J. C. Mermilliod
Keyword(s):  
Comparative Study ◽  
Age Groups ◽  
Age Determination ◽  
Open Clusters ◽  
Red Giants ◽  
Be Stars ◽  
Stellar Content ◽  
Blue Stragglers ◽  
The Mean ◽  
Hr Diagram

75 young open clusters have been divided into 14 age groups on the basis of their MV/U-B diagrams. Composite HR diagrams have been constructed and empirical isochronous curves estimated (Figure 1). The left envelope defines a ZAMS. The mean position of the red giants in the HR diagram has been investigated, as well as the occurrence and location of Ap, Am and Be stars and of blue stragglers. Red giants appear mainly in clumps (shaded area).

scholarly journals Hipparcos Positions of B/Be Stars on the HR Diagram

2000 ◽  
Vol 175 ◽  
pp. 117-128 ◽  
Author(s):  
Danielle Briot ◽  
Noel Robichon
Keyword(s):  
Spectral Type ◽  
Rotational Velocity ◽  
Absolute Magnitude ◽  
Be Stars ◽  
Class V ◽  
B Stars ◽  
Luminosity Class ◽  
The Mean ◽  
Absolute Magnitudes ◽  
Hipparcos Parallax

AbstractAbsolute magnitudes of Be and B stars are computed for each spectral type and luminosity class V and IV, using the Hipparcos parallax measurements. Some simulations have been carried out in order to estimate the effects which could bias the mean absolute magnitude calculations. As a result, only stars with σπ/π < 15% have been used. A first result is that B stars are fainter than previous estimations by about 0.5 magnitude on average. We then observe that on average Be stars are brighter than B stars of the same spectral type and this over-luminosity increases with the spectral type. A possible interpretation is proposed based on the fact that the rotational velocity of the late Be stars is near the critical rotational velocity.

scholarly journals Search for Pulsational Instability among h Persei Stars

1995 ◽  
Vol 155 ◽  
pp. 299-300
Author(s):  
J. Krzesinski
Keyword(s):  
Northern Hemisphere ◽  
Open Clusters ◽  
Age Group ◽  
Be Stars ◽  
Double Cluster

AbstractThe northern-hemisphere double cluster h and χ Persei is one of the richest young open clusters. At least half of the brightest stars in the cluster appear to be variables and most of them axe Be stars. Till now there was no evidence for the presence of β Cephei stars in the cluster. It is remarkable that the similar age southern cluster NGC 3293 and other clusters belonging to the same age group are documented as clusters in which β Cephei stars have been observed. In this work we report finding one suspected β Cephei-like object, basing on our own observations.

scholarly journals Photometric characteristics of the Be stars: almost twenty years of UBV monitoring at the Hvar observatory

1994 ◽  
Vol 162 ◽  
pp. 301-302
Author(s):  
K. Pavlovski ◽  
H. Božić ◽  
Ž. Ružić ◽  
P. Harmanec ◽  
J. Horn ◽  
...  
Keyword(s):  
Be Stars ◽  
Photoelectric Photometry ◽  
Ample Evidence ◽  
Large Group ◽  
Almost All ◽  
By Products

Since their discovery (by Father Secchi in 1866) until the end of sixties, Be stars were not a subject of any systematic studies of their possible light and colour variations. Already at that time, the astronomical literature contained ample evidence showing that a number of Be stars were light variables. However, almost all such findings resulted as by-products of studies of different or wider groups of objects. Feinstein (1968) was probably the first who pointed out explicitly that many Be stars are light variables. A pioneering study which was aimed at the detection of light variations of a large group of Be stars by means of differential photoelectric photometry was carried out by Haupt & Schroll (1974).

scholarly journals Abundances of Be Stars in Very Young Open Clusters

2000 ◽  
Vol 175 ◽  
pp. 59-62 ◽  
Author(s):  
A. Marco ◽  
G. Bernabeu ◽  
J.M. Torrejón ◽  
J.J. Rodes ◽  
J. Fabregat
Keyword(s):  
Open Clusters ◽  
Be Stars ◽  
Ccd Photometry ◽  
The Galaxy

AbstractWe present here standard uvbyβ CCD photometry for five open clusters of the Galaxy in order to determine abundances of Be stars, as a function of age.

scholarly journals VARIABILITY OF Be STARS IN SOUTHERN OPEN CLUSTERS

2009 ◽  
Vol 700 (2) ◽  
pp. 1216-1232 ◽  
Author(s):  
M. Virginia McSwain ◽  
Wenjin Huang ◽  
Douglas R. Gies
Keyword(s):  
Open Clusters ◽  
Be Stars

scholarly journals Be stars in open clusters. I. uvby $ ^{\bf \beta}$ photometry

1996 ◽  
Vol 119 (2) ◽  
pp. 271-279 ◽  
Author(s):  
J. Fabregat ◽  
J. M. Torrejón ◽  
P. Reig ◽  
G. Bernabeu ◽  
J. Busquets ◽  
...  
Keyword(s):  
Open Clusters ◽  
Be Stars

scholarly journals Be stars in open clusters

1997 ◽  
Vol 124 (2) ◽  
pp. 329-347 ◽  
Author(s):  
J. M. Torrejón ◽  
J. Fabregat ◽  
G. Bernabeu ◽  
S. Alba
Keyword(s):  
Open Clusters ◽  
Be Stars

scholarly journals Astrometric and photometric observations of six brightest trans-Neptunian objects at the Kyiv comet station

2020 ◽  
Vol 10 (2) ◽  
pp. 48-54
Author(s):  
A. Baransky ◽  
O. Lukina ◽  
S. Borysenko
Keyword(s):  
Ccd Camera ◽  
Photometric System ◽  
Photometric Observations ◽  
Absolute Magnitudes ◽  
Colour Indices

In this work we focused on observations of six trans-Neptunian objects (TNOs) whose apparent magnitudes are brighter than 20m. We present the results of astrometric and photometric observations of (134340) Pluto, (136108) Haumea, (136472) Makemake, (136199) Eris, (90482) Orcus, and (20000) Varuna obtained at the Kyiv comet station (Code MPC 585) in 2017-2019. For observations we used the 0.7-m (f/4) reflector AZT-8 with FLI PL4710 CCD camera and filters of Johnson-Cousins photometric system. From our images we measured the objects' astrometric positions, calculated apparent magnitudes in the BVRI (mostly R) bands using aperture photometry method, and found absolute magnitudes together with the colour indices in several bands. Analysing our results, we investigate the limitation on the astrometry and photometry of faint objects with the 0.7-m telescope.

Sign in / Sign up

Export Citation Format

Share Document