scholarly journals Short-Periodic Radial Velocity Variations of the B9P Star ET and

1986 ◽  
Vol 90 ◽  
pp. 235-238
Author(s):  
E. Gerth
Keyword(s):  
Binary System ◽  
Radial Velocity ◽  
Close Binary System ◽  
Close Binary ◽  
National Observatory ◽  
Spectroscopic Observations ◽  
Short Period ◽  
Velocity Variations

AbstractSpectroscopic observations of the B9p star ET and secured at the Bulgarian National Observatory Roshen in the years 1981–1984, consisting of 97 plates, show clearly a radial velocity period of 0.198 d - with a ratio to the photometrical period of exactly 2:1. This behaviour would hint at a close binary system; but there arise difficulties in explaining it by this way because of the extreme short period, so that pulsation must be taken into account. However, besides of the confident period of 0.198 d, there is evidence for shorter periods in the region of 45 min, which may be attributed only to pulsational processes.

scholarly journals The Search for Close Binary Evolved Stars

1989 ◽  
Vol 114 ◽  
pp. 408-412
Author(s):  
Rex A. Saffer ◽  
James Liebert
Keyword(s):  
Binary System ◽  
White Dwarf ◽  
White Dwarfs ◽  
Binary Systems ◽  
Close Binary ◽  
Brown Dwarf ◽  
Null Results ◽  
Spectroscopic Observations ◽  
Evolved Stars ◽  
Short Period

AbstractWe report on a search for short-period binary systems composed of pairs of evolved stars. The search is being carried out concurrently with a program to characterize the kinematical properties of two different samples of stars. Each sample has produced one close binary candidate for which further spectroscopic observations are planned. We also recapitulate the discovery of a close detached binary system composed of two cool DA white dwarfs, and we discuss the null results of Hα observations of the suspected white dwarf/brown dwarf system G 29–38.

On the Possible Short-Period Irregular Light Fluctuations of V1357 CYG =CYG X-1

1982 ◽  
Vol 69 ◽  
pp. 467-472
Author(s):  
M.I. Kumsiashvili ◽  
Z. Kraicheva
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
X Ray ◽  
Light Fluctuations ◽  
Short Period ◽  
Photoelectric Observations ◽  
Fast Light

AbstractPhotoelectric observations in U, B, V, were carried out to study the possible rapid (during a night) fluctuations of the close binary system V1357 Cyg, including the X-ray source Cyg X-1. Assuming the existence of irregular fast light fluctuations in the X-ray source Cyg X-1,the conclusion can be drawn that during these observations in 1979 the amplitude of the variations did not exceed 0.04 mag.

scholarly journals The ROSAT view of the massive eclipsing O-type binary system 29 UW Canis Majoris

1995 ◽  
Vol 163 ◽  
pp. 382-387
Author(s):  
Thomas W. Berghöfer ◽  
Jürgen H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Stellar Winds ◽  
X Ray ◽  
Short Period

We have investigated a recently obtained ROSAT X-ray observation of the massive binary 29 UW Canis Majoris (HR 2781; HD 57060). This short-period binary (4.3934 d) consists of two eclipsing O-type stars and has been observed for about 9 days with the ROSAT PSPC. We discuss the origin of the X-ray emission in the close binary system 29 CMa in the context of the traditional colliding wind scenario as well as the scenario of X-ray emission from shock heated gas in the stellar winds.

scholarly journals Period Variation of the Pop.II Cepheid AU Peg

1993 ◽  
Vol 139 ◽  
pp. 423-424
Author(s):  
J. Vinko
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Period Variation ◽  
Close Binary ◽  
Simple Explanation ◽  
Tidal Interaction ◽  
Short Period ◽  
Non Linear ◽  
Type Variable

AbstractAU Peg, a short period BL Her-type variable, is unique among short period Cepheids. It is a member of a close binary system with an unseen companion. In t his paper the pulsational period variation is presented. It is shown that the period variation is very rapid and highly non-linear. It seems that there is no simple explanation of this phenomena by standard evolution or tidal interaction.

scholarly journals Marginally low mass ratio close binary system V1191 Cyg

New Astronomy ◽  
2012 ◽  
Vol 17 (1) ◽  
pp. 46-49 ◽  
Author(s):  
B. Ulaş ◽  
B. Kalomeni ◽  
V. Keskin ◽  
O. Köse ◽  
K. Yakut
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Mass Ratio ◽  
Low Mass ◽  
Low Mass Ratio

scholarly journals Asteroseismology in action: a test of spin-orbit synchronism in the close binary system Feige 48

2008 ◽  
Vol 483 (3) ◽  
pp. 875-885 ◽  
Author(s):  
V. Van Grootel ◽  
S. Charpinet ◽  
G. Fontaine ◽  
P. Brassard
Keyword(s):  
Binary System ◽  
Close Binary System ◽  
Close Binary ◽  
Spin Orbit

Radial Velocity Variations in Cool Supergiants

1984 ◽  
Vol 88 ◽  
pp. 283-288
Author(s):  
Hugh C. Harris
Keyword(s):  
Radial Velocity ◽  
Main Sequence ◽  
Short Period ◽  
Cool Stars ◽  
Synchronous Rotation ◽  
Red Supergiants ◽  
Velocity Variations ◽  
Orbital Periods ◽  
Low Amplitude ◽  
Good Agreement

AbstractA survey of F, G, and W supergiants has been carried out with the DAO radial velocity spectrometer, an efficient instrument for detecting low-amplitude velocity variations in cool stars. Observations of 78 stars over five seasons show generally good agreement with OORAVEL results for spectroscopie binaries. The majority of supergiants show low-amplitude variability, with amplitudes typically 1 to 2 km s−1. The width of the cross-correlation profile has been measured for 58 supergiants. It reveals 14 stars with unusually broad lines, indicative of rotation velocities of 15 to 35 km s−1. Several have short-period binary companions and may be in synchronous rotation. The other broad-lined stars are apparently single or with long orbital periods; they may be making their first transition from the main sequence to become red supergiants.

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