scholarly journals Time-Resolved Ultraviolet Observations of the Globular Cluster X-Ray Source in NGC 6624: The Shortest Known Period Binary System

1997 ◽  
Vol 482 (1) ◽  
pp. L69-L72 ◽  
Author(s):  
Scott F. Anderson ◽  
Bruce Margon ◽  
Eric W. Deutsch ◽  
Ronald A. Downes ◽  
Richard G. Allen
Keyword(s):  
Binary System ◽  
Globular Cluster ◽  
Time Resolved ◽  
X Ray ◽  
Ultraviolet Observations

scholarly journals Infrared observations and mass loss of the binary system V861 Sco

1981 ◽  
Vol 59 ◽  
pp. 477-480 ◽  
Author(s):  
E.G. Tanzi ◽  
L. Maraschi ◽  
M. Tarenghi ◽  
A. Treves
Keyword(s):  
Binary System ◽  
Mass Loss ◽  
Mass Flow ◽  
Secondary Component ◽  
Single Line ◽  
Infrared Excess ◽  
Infrared Observations ◽  
X Ray ◽  
Photometric Observations ◽  
Ultraviolet Observations

V 861 Sco (HD 152667) is a well known single line binary(1,2).The proposed association with a variable X-ray source(3,4) has triggered renewed interest in the system. Recent optical, infrared and ultraviolet observations(5 - 12) have provided a better knowledge of its characteristics. A first estimate of the mass loss was given by Hutchings(13).Here we report on a series of photometric observations in the infrared (from 1.25 to 4.8 µ) taken at various orbital phases which improve and extend previous measurements by Tanzi et al.(12)The results give evidence of a phase modulated infrared excess which can be interpreted in terms of a non isotropic mass flow in the system or, alternately, of a contribution from a colder secondary component.

Origin of Very-Short Orbital-Period Binary Systems

1983 ◽  
Vol 72 ◽  
pp. 263-267
Author(s):  
Shigeki Miyaji
Keyword(s):  
Binary System ◽  
Globular Cluster ◽  
Orbital Period ◽  
Binary Systems ◽  
Main Sequence ◽  
Cataclysmic Variables ◽  
Close Binaries ◽  
X Ray ◽  
Evolutionary Scenario ◽  
Orbital Periods

Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both x-ray close binaries (4U1626-67; Middleditch et al. 1981 and 4U1916 -0.5; White and Swank 1982) and cataclysmic variables (AM CVn; Faulkner et al. 1972 and G61-29; Nather et al. 1981). Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of them belongs to any globular cluster, are too abundant to be explained by capturing mechanism of a white dwarf. Therefore it seemed to be worth to present an evolutionary scenario from an original binary system which can be applied for all of VSOP binaries.

Time-resolved imaging and spectral studies of an X-ray burst from the globular cluster Terzan

1980 ◽  
Vol 240 ◽  
pp. L121 ◽  
Author(s):  
J. E. Grindlay ◽  
H. L. Marshall ◽  
P. Hertz ◽  
M. C. Weisskopf ◽  
R. F. Elsner ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Spectral Studies ◽  
Time Resolved ◽  
X Ray ◽  
Time Resolved Imaging

Optical and ultraviolet observations of the X-ray globular cluster BO 158 in M31

1982 ◽  
Vol 261 ◽  
pp. 77 ◽  
Author(s):  
C. Cacciari ◽  
A. Cassatella ◽  
L. Bianchi ◽  
F. Fusi Pecci ◽  
R. G. Kron
Keyword(s):  
Globular Cluster ◽  
X Ray ◽  
Ultraviolet Observations

Recent Optical Observations of the X-Ray Source H0139-68; an AM-Herculis Type Binary System

1982 ◽  
Vol 4 (4) ◽  
pp. 425-428
Author(s):  
A.J. Pickles ◽  
N. Visvanathan
Keyword(s):  
Binary System ◽  
Low Energy ◽  
Optical Observations ◽  
Short Time Scale ◽  
Optical Identification ◽  
Time Resolved ◽  
X Ray ◽  
Short Time ◽  
Energy Detectors ◽  
Optical Spectrophotometry

The soft X-ray source HO 139-68 was originally detected with the low energy detectors of the HEAO A-2 experiment, and confirmed by later IPC observations (Agarwal et al. 1981). The X-ray observations show flux variations in the 0.15 – 0.4 keV band of a factor of two, or timescales of a few hours, with evidence for short time-scale flickering. Following communication of the source position to us by Agarwal and Riegler, we obtained time-resolved optical spectrophotometry of a star close to the X-ray position, using the IDPCA on the MSO 1.9m telescope. The spectrophotometry and later polarisation observations confirm the optical identification and that the source is an AM-Herculis type binary system, with a late type dwarf secondary overflowing its Roche lobe in a magnetically constrained funnel onto a magnetic white dwarf (WD) primary (Visvanathan and Pickles 1982).

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

High temperature 27Al NMR time resolved study. Application to the CaO-Al2O3 binary system

1995 ◽  
Vol 92 ◽  
pp. 1871-1876 ◽  
Author(s):  
B Touzo ◽  
D Trumeau ◽  
D Massiot ◽  
I Farnan ◽  
JP Coutures
Keyword(s):  
High Temperature ◽  
Binary System ◽  
27Al Nmr ◽  
Time Resolved ◽  
Study Application

Time-resolved X-ray reciprocal space mapping of the crystal under external electric field

2018 ◽  
Vol 189 (02) ◽  
pp. 187-194 ◽  
Author(s):  
Nikita V. Marchenkov ◽  
Anton G. Kulikov ◽  
Ivan I. Atknin ◽  
Arsen A. Petrenko ◽  
Alexander E. Blagov ◽  
...  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
Time Resolved ◽  
X Ray
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