Double and Multiple Star Speckle Observations at the 6-m Telescope

During the last 15 years more than 9,000 speckle interferometric measurements of binary stars have been collected using large optical telescopes (McAlister & Hartkopf 1988). Among them a significant contribution to the world speckle data has been made by the 6-m telscope near Zelenchuk. Up to now this instrument provides the maximal spatial resolution for single–aperture telescopes. First speckle images of the binary Capella were recorded at the telescope in 1977 (Balega & Tikhonov 1977), but we spent 5 more years to create special television techniques for photon counting and digital means for image processing before we started the regular interferometric program of binary observations in the wide range of stellar magnitudes. At first, the measurements were conducted in cooperation with French astronomers from the Centre d’Etudes et de Recherches Geodynamiques et Astronomiques using the optical camera and the television detector developed by Blazit et al. (1977). Since 1983 our equipment has been in use. The program of observations was oriented upon the traditional problems of multiple star speckle interferometry:1.Determination of stellar distances and masses for different types of binaries whose orbital elements can be derived. This includes already known fast visual and astrometric pairs with undetermined orbits, spectroscopic binaries that can be resolved directly, and newly discovered interferometric pairs which show fast orbital motion. The main attention was devoted to the late–type dwarfs in the vicinity of the Sun.2.Search for the secondary components whose existence could explain anomalies of stellar spectra or photometry (stars with composite spectra, occultation binaries, etc.)3.Study of unusual binaries (symbiotic stars, binaries with relativistic components, such as SS 433, etc.)

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The Potential of Long–Baseline Optical Interferometry of Binary Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100007053 ◽

1992 ◽

Vol 135 ◽

pp. 527-535 ◽

Cited By ~ 3

Author(s):

H.A. McAlister

Keyword(s):

Binary Stars ◽

Speckle Interferometry ◽

Stellar Mass ◽

Optical Interferometry ◽

Spectroscopic Binaries ◽

Direct Imaging ◽

Multiple Star ◽

Long Baseline ◽

Stellar Interferometer

AbstractInterferometric arrays possessing sub-milliarcsecond resolution are either about to be fully scientifically productive, as in the case of the Sydney University Stellar Interferometer, or are under various stages of planning and development. The 1990’s will thus witness a hundred–fold gain in resolution over speckle interferometry at the largest telescopes and 5,000 times the resolution of classical direct imaging. Where speckle interferometry can now resolve binary stars with periods of 1 to 2 years, interferometric arrays with baselines of hundreds of meters will resolve binaries with periods of a few hours. Arrays will resolve the majority of the known spectroscopic binaries, providing a substantial increase in the quantity and quality of stellar mass determinations. Surveys for new binaries among the field stars and other restricted samples will be accomplished with unprecedented completeness. The remarkable enhancement in resolution we are about to witness from facilities like SUSI and our own proposed CHARA Array will quite literally revolutionize the field of double and multiple star research.

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Computer simulations of speckle interferometry of binary stars in the photon-counting mode

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/183.2.223 ◽

1978 ◽

Vol 183 (2) ◽

pp. 223-236 ◽

Cited By ~ 16

Author(s):

J. C. Dainty

Keyword(s):

Computer Simulations ◽

Binary Stars ◽

Photon Counting ◽

Speckle Interferometry ◽

Counting Mode ◽

Photon Counting Mode

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Binary star astrometry with milli and sub-milli arcsecond precision

Serbian Astronomical Journal ◽

10.2298/saj1488001j ◽

2014 ◽

pp. 1-21

Author(s):

S. Jankov ◽

Z. Cvetkovic ◽

R. Pavlovic

Keyword(s):

Adaptive Optics ◽

Binary Stars ◽

Binary Star ◽

Speckle Interferometry ◽

Spectroscopic Binaries ◽

Fundamental Parameters ◽

Long Baseline ◽

Short Period ◽

Observational Techniques ◽

Near Future

The past several decades have seen accelerating progress in improving binary stars fundamental parameters determinations, as new observational techniques have produced visual orbits of many spectroscopic binaries with a milli arcsecond precision. Modern astrometry is rapidly approaching the goal of sub-milli arcsecond precision, and although presently this precision has been achieved only for a limited number of binary stars, in the near future this will become a standard for very large number of objects. In this paper we review the representative results of techniques which have already allowed the sub-milli arcsecond precision like the optical long baseline interferometry, as well as the precursor techniques such as speckle interferometry, adaptive optics and aperture masking. These techniques provide a step forward from milli to sub-milli arcsecond precision, allowing even short period binaries to be resolved, and often resulting in orbits allowing precisions in stellar dynamical masses better than 1%. We point out that such unprecedented precisions should allow for a significant improvement of our comprehension of stellar physics and other related astrophysical topics.

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Detectivity optimization to detect of ultraweak light fluxes with an EM-CCD as binary photon counter array

Scientific Reports ◽

10.1038/s41598-021-82611-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ibtissame Khaoua ◽

Guillaume Graciani ◽

Andrey Kim ◽

François Amblard

Keyword(s):

Dynamic Range ◽

Signal To Noise Ratio ◽

Photon Counting ◽

Detection Methods ◽

Strong Nonlinearity ◽

Wide Range ◽

Depth Analysis ◽

Spatially Extended ◽

Extended Sources ◽

Photon Counting Mode

AbstractFor a wide range of purposes, one faces the challenge to detect light from extremely faint and spatially extended sources. In such cases, detector noises dominate over the photon noise of the source, and quantum detectors in photon counting mode are generally the best option. Here, we combine a statistical model with an in-depth analysis of detector noises and calibration experiments, and we show that visible light can be detected with an electron-multiplying charge-coupled devices (EM-CCD) with a signal-to-noise ratio (SNR) of 3 for fluxes less than $$30\,{\text{photon}}\,{\text{s}}^{ - 1} \,{\text{cm}}^{ - 2}$$ 30 photon s - 1 cm - 2 . For green photons, this corresponds to 12 aW $${\text{cm}}^{ - 2}$$ cm - 2 ≈ $$9{ } \times 10^{ - 11}$$ 9 × 10 - 11 lux, i.e. 15 orders of magnitude less than typical daylight. The strong nonlinearity of the SNR with the sampling time leads to a dynamic range of detection of 4 orders of magnitude. To detect possibly varying light fluxes, we operate in conditions of maximal detectivity $${\mathcal{D}}$$ D rather than maximal SNR. Given the quantum efficiency $$QE\left( \lambda \right)$$ Q E λ of the detector, we find $${ \mathcal{D}} = 0.015\,{\text{photon}}^{ - 1} \,{\text{s}}^{1/2} \,{\text{cm}}$$ D = 0.015 photon - 1 s 1 / 2 cm , and a non-negligible sensitivity to blackbody radiation for T > 50 °C. This work should help design highly sensitive luminescence detection methods and develop experiments to explore dynamic phenomena involving ultra-weak luminescence in biology, chemistry, and material sciences.

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Physical Parameters and Chemical Composition of Components of the Am-Type Binary System RR Lyncis

International Astronomical Union Colloquium ◽

10.1017/s0252921100020509 ◽

1993 ◽

Vol 138 ◽

pp. 192-196

Author(s):

L.S. Lyubimkov ◽

T.M. Rachkovskaya

Keyword(s):

Chemical Composition ◽

Binary System ◽

Binary Stars ◽

Spectroscopic Binaries ◽

Theoretical Modelling ◽

Physical Parameters ◽

Accurate Data ◽

Element Abundances ◽

Widespread Phenomenon ◽

Chemical Anomalies

Duplicity is a very widespread phenomenon among Am-stars. For instance, Abt (1961) investigating 25 such stars found out that 22 of them are spectroscopic binaries. However this important phenomenon is ignored usually in chemical composition investigations of Am-stars. Consequently some “mean” element abundances are determined, which can noticeably differ from real abundances in atmospheres of components. Moreover false chemical anomalies can appear, as shown by the theoretical modelling of spectra of binary stars (Lyubimkov, 1989, 1992). Meanwhile accurate data on chemical composition of Am-stars must be considered as observational test for any hypothesis suggested for explanation of these objects.

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Long-Term Coudé Radial-Velocity Studies With a 1.2-m Telescope

International Astronomical Union Colloquium ◽

10.1017/s0252921100079094 ◽

2001 ◽

Vol 183 ◽

pp. 283-288

Author(s):

C.D. Scarfe

Keyword(s):

Radial Velocity ◽

Binary Stars ◽

Star System ◽

Standard Star ◽

Stellar Spectra ◽

Multiple Stars ◽

Binary And Multiple Stars ◽

Selection Of

AbstractI have used the 1.2-m telescope and coudé spectrograph of the Dominion Astrophysical Observatory for more than 30 years in a program of radial-velocity observations of binary stars. The program was begun with photographic plates as detectors, but for 20 years the primary detector has been the radial-velocity scanner, which cross-correlates stellar spectra with an artificial mask.Since some of the binaries under observation have periods of several years, the instrument’s stability is an important consideration. I have therefore been obliged to observe standard stars and asteroids to check its performance. These observations are of relevance to efforts to improve the IAU standard star system.I will describe the telescope, spectrograph and scanner, and will briefly discuss some of the results obtained for a selection of binary and multiple stars.

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Signal to noise ratio in speckle interferometry in the photon counting autocorrelation mode at low light levels

Optics Communications ◽

10.1016/0030-4018(79)90098-1 ◽

1979 ◽

Vol 29 (3) ◽

pp. 273-278 ◽

Cited By ~ 6

Author(s):

J.G. Walker

Keyword(s):

Signal To Noise Ratio ◽

Photon Counting ◽

Speckle Interferometry ◽

Signal To Noise ◽

Low Light ◽

Light Levels ◽

Noise Ratio

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Detector commissioning and development for PETRA-III

Diamond Light Source Proceedings ◽

10.1017/s2044820110000043 ◽

2010 ◽

Vol 1 (SRMS-7) ◽

Cited By ~ 1

Author(s):

David Pennicard ◽

Heinz Graafsma ◽

Michael Lohmann

Keyword(s):

High Speed ◽

Materials Science ◽

Dynamic Range ◽

Photon Counting ◽

High Energy ◽

X Rays ◽

Silicon Detectors ◽

Time Resolved ◽

Wide Range ◽

Synchrotron Light

The new synchrotron light source PETRA-III produced its first beam last year. The extremely high brilliance of PETRA-III and the large energy range of many of its beamlines make it useful for a wide range of experiments, particularly in materials science. The detectors at PETRA-III will need to meet several requirements, such as operation across a wide dynamic range, high-speed readout and good quantum efficiency even at high photon energies. PETRA-III beamlines with lower photon energies will typically be equipped with photon-counting silicon detectors for two-dimensional detection and silicon drift detectors for spectroscopy and higher-energy beamlines will use scintillators coupled to cameras or photomultiplier tubes. Longer-term developments include ‘high-Z’ semiconductors for detecting high-energy X-rays, photon-counting readout chips with smaller pixels and higher frame rates and pixellated avalanche photodiodes for time-resolved experiments.

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